|Abstracts on Global Climate Change|
Water in the Earth’s atmosphere
Quante, M Matthias, V
JOURNAL DE PHYSIQUE IV 139: 37-61
Water is the key to our existence on this planet and it is involved in nearly all biological, geological, and chemical processes. Life on Earth depends very much on the remarkable properties of water. The availability of freshwater is for many regions one of the key concerns in connection with global climate change. The atmosphere contains only about 0.001% of the water available on our planet. Despite this small amount its horizontal and vertical distribution plays a key role in the global water cycle and the Earth’s climate. The atmosphere has direct connections to most of the other reservoirs and steers the redistribution of water between them with an average turnover time of about 10 days. Evaporation over the oceans exceeds precipitation and over land evapotranspiration amounts only to 2/3 of the precipitation reaching the ground. Consequently, there is a net flux of water from the oceans towards the continents, of course via the atmosphere, which has the largest overall volume of fluxes. Water is present in the atmosphere as solid, liquid, or gas. Water vapour is the most important greenhouse gas in the atmosphere and, in addition, changes of water phase and cloud-radiation interaction contribute strongly to the global energy cycle. Water is also a physically and chemically integral part of other biogeochemical cycles. Although there have been large efforts and improvements in recent years, uncertainties in quantifying the components of the atmospheric water cycle still exist. Observational capabilities on the global scale are not satisfactory at present, but the advent of new satellites devoted to the global observation of precipitation and cloud systems along with dedicated modelling projects certainly will improve the situation. Progress is urgently needed to adequately contribute to the answer of one of the central questions in the context of global warming: Is the hydrological cycle accelerating?.
Evaluating long-term trends in annual and seasonal precipitation in Taiwan
Yu, PS Yang, TC Kuo, CC
WATER RESOURCES MANAGEMENT 20:6 1007-1023
This work studies long-term rainfall variations in Taiwan and provides local climate change analyses to global climate change. Around a century of rainfall data from 33 rain-gauges populate the database used herein. Statistical tests, such as cumulative deviations, Mann-Whitney-Pettitt statistics and the Kruskal-Wallis test, were first employed to determine whether annual rainfall series exhibit any regular trend. Analytical results indicate that the annual rainfall has increased in northern Taiwan, declined in central and southern Taiwan, and exhibited no clear tendency in Eastern Taiwan. Almost all of these rainfall series changed significantly around 1960, which date divides historical rainfall series into two sample groups. This change in the seasonal rainfall was further investigated.
A land surface model incorporated with soil freeze/thaw and its application in GAME/Tibet
Hu, HP Ye, BS Zhou, YH Tian, FQ
SCIENCE IN CHINA SERIES D-EARTH SCIENCES 49:12 1311-1322
Land surface process is of great importance in global climate change, moisture and heat exchange in the interface of the earth and atmosphere, human impacts on the environment and ecosystem, etc. Soil freeze/thaw plays an important role in cold land surface processes. In this work the diurnal freeze/thaw effects on energy partition in the context of GAME/Tibet are studied. A sophisticated land surface model is developed, the particular aspect of which is its physical consideration of soil freeze/thaw and vapor flux. The simultaneous water and heat transfer soil sub-model not only reflects the water flow from unfrozen zone to frozen fringe in freezing/thawing soil, but also demonstrates the change of moisture and temperature field induced by vapor flux from high temperature zone to low temperature zone, which makes the model applicable for various circumstances. The modified Picard numerical method is employed to help with the water balance and convergence of the numerical scheme. Finally, the model is applied to analyze the diurnal energy and water cycle characteristics over the Tibetan Plateau using the Game/Tibet datasets observed in May and July of 1998. Heat and energy transfer simulation shows that: (i) There exists a negative feedback mechanism between soil freeze/thaw and soil temperature/ground heat flux; (ii) during freezing period all three heat fluxes do not vary apparently, in spite of the fact that the negative soil temperature is higher than that not considering soil freeze; (iii) during thawing period, ground heat flux increases, and sensible heat flux decreases, but latent heat flux does not change much; and (iv) during freezing period, soil temperature decreases, though ground heat flux increases.
Personal values, beliefs, and ecological risk perception
Slimak, MW Dietz, T
RISK ANALYSIS 26:6 1689-1705
A mail survey on ecological risk perception was administered in the summer of 2002 to a randomized sample of the lay public and to selected risk professionals at the U.S. Environmental Protection Agency (US EPA). The ranking of 24 ecological risk items, from global climate change to commercial fishing, reveals that the lay public is more concerned about low-probability, high-consequence risks whereas the risk professionals are more concerned about risks that pose long-term, ecosystem-level impacts. To test the explanatory power of the value-belief-norm (VBN) theory for risk perception, respondents were questioned about their personal values, spiritual beliefs, and worldviews. The most consistent predictors of the risk rankings are belief in the new ecological paradigm (NEP) and Schwartz’s altruism. The NEP and Schwartz’s altruism explain from 19% to 46% of the variance in the risk rankings. Religious beliefs account for less than 6% of the variance and do not show a consistent pattern in predicting risk perception although religious fundamentalists are generally less concerned about the risk items. While not exerting as strong an impact, social-structural variables do have some influence on risk perception. Ethnicities show no effect on the risk scales but the more educated and financially well-off are less concerned about the risk items. Political leanings have no direct influence on risk rankings, but indirectly affect rankings through the NEP. These results reveal that the VBN theory is a plausible explanation for the differences measured in the respondents’ perception of ecological risk.
Predicting woodrat (Neotoma) responses to anthropogenic warming from studies of the palaeomidden record
Smith, FA Betancourt, JL
JOURNAL OF BIOGEOGRAPHY 33:12 2061-2076
Aim The influence of anthropogenic climate change on organisms is an area of great scientific concern. Increasingly there is recognition that abrupt climate transitions have occurred over the late Quaternary; studies of these shifts may yield insights into likely biotic responses to contemporary warming. Here, we review research undertaken over the past decade investigating the response of Neotoma (woodrats) body size and distribution to climate change over the late Quaternary (the last 40,000 years). By integrating information from woodrat palaeomiddens, historical museum specimens and field studies of modern populations, we identify potential evolutionary responses to climate change occurring over a variety of temporal and spatial scales. Specifically, we characterize climatic thresholds in the past that led to local species extirpation and/or range alterations rather than in situ adaptation, and apply them to anticipate potential biotic responses to anthropogenic climate change. Location Middens were collected at about 55 sites scattered across the western United States, ranging from about 34 to 46 degrees N and about 104 to 116 degrees W, respectively. Data for modern populations were drawn from studies conducted in Death Valley, California, Missoula, Montana and the Sevilleta LTER site in central New Mexico. Methods We analysed faecal pellets from midden series collected at numerous cave sites across the western United States. From these we estimated body mass using techniques validated in earlier studies. We compared body size fluctuations at different elevations in different regions and integrated these results with studies investigating temperature-body size tradeoffs in modern animals. We also quantify the rapidity of the size changes over the late Quaternary to estimate the evolutionary capacity of woodrats to deal with predicted rates of anthropogenic climate change over the next century. Results We find remarkable similarities across the geographical range to late Quaternary climate change. In the middle of the geographical range woodrats respond in accordance to Bergmann’s rule: colder climatic conditions select for larger body size and warmer conditions select for smaller body size. Patterns are more complicated at range boundaries, and local environmental conditions influence the observed response. In general, woodrat body size fluctuates with approximately the same amplitude and frequency as climate; there is a significant and positive correlation between woodrat body size and generalized climate proxies (such as ice core records). Woodrats have achieved evolutionary rates of change equal to or greater than those needed to adapt in situ to anthropogenic climate change. Main conclusions In situ body size evolution is a likely outcome of climate change, and such shifts are part of a normal spectrum of adaptation. Woodrats appear to be subject to ongoing body size selection in response to fluctuating environmental conditions. Allometric considerations suggest that these shifts in body size lead to substantial changes in the physiology, life history and ecology of woodrats, and on their direct and indirect interactions with other organisms in the ecosystem. Our work highlights the importance of a finely resolved and long-term record in understanding biotic responses to climatic shifts.
Interhemispheric anti-phasing of rainfall during the last glacial period
Wang, XF Auler, AS Edwards, RL Cheng, H Ito, E Solheid, M
QUATERNARY SCIENCE REVIEWS 25:23-24 3391-3403
We have obtained a high-resolution oxygen isotopic record of cave calcite from Caverna Botuvera (27 degrees 13’S, 49 degrees 09’W), southern Brazil, which covers most of the last 36 thousand years (ka), with an average resolution of a few to several decades. The chronology was determined with 46 U/Th ages from two stalagmites. Tests for equilibrium conditions show that oxygen isotopic variations are primarily caused by climate change. We interpret our record in terms of meteoric precipitation changes, hence the variability of South American Monsoon (SAM) intensity. The oxygen isotopic profile broadly follows local insolation changes and shows clear millennial-scale variations during the last glacial period with amplitudes as large as 3 parts per thousand but with smaller centennial-scale shifts (< 1 parts per thousand) during the Holocene. The overall record is strikingly similar to, but strongly anti-correlated with, a number of records from the Northern Hemisphere. We compared our record to other precisely dated contemporaneous records from Hulu Cave eastern China. Minima in 6180 (wet periods, intense SAM) at our site are synchronous with maxima in delta O-18 (dry periods, weak East Asian Monsoon, EAM) in eastern China (within precise dating errors) and vice versa. This anti-phased precipitation relationship between two low-latitude locations may be interhemispheric in extent, based on comparison with records from other sites. Precipitation anti-phasing may be related to north-south shifts in the mean position of the intertropical convergence zone (ITCZ) and asymmetry in Hadley circulation in two hemispheres, associated not with seasonal changes as observed today, but with millennial-scale climate shifts. The millennial-scale atmospheric see-saw patterns that we observe could have important controls and feedbacks on climate within hemispheres because of water vapor’s greenhouse properties. (c) 2006 Elsevier Ltd. All rights reserved.
Frequency of debris flows and rockfall along the Mendoza river valley (Central Andes), Argentina: Associated risk and future scenario
QUATERNARY INTERNATIONAL 158: 110-121
The frequency of debris flows and rockfalls was estimated by temporal distribution of these events during the last 50 years. This parameter was expressed by annual probability of occurrence and mean interval of recurrence of historical events. More recurrent events in this sector of the Central Andes are associated with the Guido locality and tunnels situated along International road No. 7. Furthermore, these events are more frequent in Cordillera Frontal where the mean recurrence interval was lower than in Precordillera. The maximum interval of recurrence is rarely greater than 20 years, showing the activity of these events on human lives and infrastructure in this region. The accuracy of the determined recurrence frequency is discussed. A future scenario indicates that landslides will be probably more frequent under global climate change. As a consequence, those most vulnerable elements in the region, the international access routes, may be severely damaged in the future, implying an adverse impact in our regional economy. (c) 2006 Elsevier Ltd and INQUA. All rights reserved.
Seasonal-to-decadal predictability and prediction of South American climate
Nobre, P Marengo, JA Cavalcanti, IFA Obregon, G Barros, V Camilloni, I Campos, N Ferreira, AG
JOURNAL OF CLIMATE 19:23 5988-6004
The dynamical basis for seasonal to decadal climate predictions and predictability over South America is reviewed. It is shown that, while global tropical SSTs affect both predictability and predictions over South America, the current lack of SST predictability over the tropical Atlantic represents a limiting factor to seasonal climate predictions over some parts of the continent. The model’s skill varies with the continental region: the highest skill is found in the “Nordeste” region and the lowest skill over southeastern Brazil. It is also suggested that current two-tier approaches to predict seasonal climate variations might represent a major limitation to forecast coupled ocean-atmosphere phenomena like the South Atlantic convergence zone. Also discussed are the possible effects of global climate change on regional predictability of seasonal climate.
Comparative risk assessment of the burden of disease from climate change
Campbell-Lendrum, D Woodruff, R
ENVIRONMENTAL HEALTH PERSPECTIVES 114:12 1935-1941
The World Health Organization has developed standardized comparative risk assessment methods for estimating aggregate disease burdens attributable to different risk factors. These have been applied to existing and new models for a range of climate-sensitive diseases in order to estimate the effect of global climate change on current disease burdens and likely proportional changes in the future. The comparative risk assessment approach has been used to assess the health consequences of climate change worldwide, to inform decisions on mitigating greenhouse gas emissions, and in a regional assessment of the Oceania region in the Pacific Ocean to provide more location-specific information relevant to local mitigation and adaptation decisions. The approach places climate change within the same criteria for epidemiologic assessment as other health risks and accounts for the size of the burden of climate-sensitive diseases rather than just proportional change, which highlights the importance of small proportional changes in diseases such as diarrhea and malnutrition that cause a large burden. These exercises help clarify important knowledge gaps such as a relatively poor understanding of the role of nonclimatic factors (socioeconomic and other) that may modify future climatic influences and a lack of empiric evidence and methods for quantifying more complex climate-health relationships, which consequently are often excluded from consideration. These exercises highlight the need for risk assessment frameworks that make the best use of traditional epidemiologic methods and that also fully consider the specific characteristics of climate change. These include the long-term and uncertain nature of the exposure and the effects on multiple physical and biotic systems that have the potential for diverse and widespread effects, including high-impact events.
Growth and physiological responses of canola (Brassica napus) to three components of global climate change: temperature, carbon dioxide and drought
Qaderi, MM Kurepin, LV Reid, DM
PHYSIOLOGIA PLANTARUM 128:4 710-721
Elevated CO2 appears to be a significant factor in global warming, which will likely lead to drought conditions in many areas. Few studies have considered the interactive effects of higher CO2, temperature and drought on plant growth and physiology. We grew canola (Brassica napus cv. 45H72) plants under lower (22/18 degrees C) and higher (28/24 degrees C) temperature regimes in controlled environment chambers at ambient (370 mu mol mol(-1)) and elevated (740 mu mol mol(-1)) CO2 levels. One half of the plants were watered to field capacity and the other half at wilting point. In three separate experiments, we determined growth, various physiological parameters and content of abscisic acid (ABA), indole-3-acetic acid and ethylene. Drought-stressed plants grown under higher temperature at ambient CO2 had decreased stem height and diameter, leaf number and area, dry matter, leaf area ratio, shoot/root weight ratio, net CO2 assimilation and chlorophyll fluorescence. However, these plants had increased specific leaf weight, leaf weight ratio and chlorophyll concentration. Elevated CO2 generally had the opposite effect, and partially reversed the inhibitory effects of higher temperature and drought on leaf dry weight accumulation. This study showed that higher temperature and drought inhibit many processes but elevated CO2 partially mitigate some adverse effects. As expected, drought stress increased ABA but higher temperature inhibited the ability of plants to produce ABA in response to drought.
Late Pliocene monsoon linkage in the tropical South China Sea
Tian, J Pak, DK Wang, PX Lea, D Cheng, XR Zhao, QH
EARTH AND PLANETARY SCIENCE LETTERS 252:1-2 72-81
The onset of Northern Hemisphere Glaciation (NHG) similar to 2.7 Ma ago coincided with prominent climate changes in the tropical regions such as the African and the Asian monsoons. However, the relationship between tropical and sub-tropical monsoonal variations and high northern latitude ice sheet expansion as well as processes such as late Pliocene tropical sea surface temperature (SST) change is not clear. Our late Pliocene (2.5-3.3 Ma) monsoon proxy records and Mg/Ca derived SST records at Ocean Drilling Program (ODP) Site 1143 from the southern South China Sea (SCS) reveal that while tropical SST shows a stepwise decrease of 2-3 degrees C during this period, the East Asian monsoon gradually strengthens in response to the onset of the NHG. At the 41-kyr and 23-kyr bands, ice volume change lags tropical SST by similar to 4 kyr, but leads the East Asian monsoon by similar to 12-17 kyr. Our finding highlights the significant role of the tropical Pacific region in driving global climate change in the late Pliocene, which has invariable leading phase relative to the ice volume change as in the late Pleistocene. However, the East Asian monsoon shows a linear response to the onset: of the NHG in the late Pliocene, with much bigger phase lagged at the 41-kyr and 23-kyr bands than in the Pleistocene, which suggests that at the obliquity and precession bands the phases of the Plio-Pleistocene East Asian monsoon variations relative to the global ice volume changes are not constant, but variable. Therefore, the East Asian monsoons are not only simply driven by northern summer insolation at the precession period but also modulated by global ice volume change in high latitudes. (c) 2006 Elsevier B.V. All rights reserved.
An atmosphere-ocean time series model of global climate change
COMPUTATIONAL STATISTICS & DATA ANALYSIS 51:2 1330-1346
Time series models of global climate change tend to estimate a low climate-sensitivity (equilibrium effect on global temperature of doubling carbon dioxide concentrations) and a fast adjustment rate to equilibrium. These results may be biased by omission of a key variable-heat stored in the ocean. A time series model of the atmosphere-ocean climate system is developed, in which surface temperature (atmospheric temperature over land and sea surface temperature) moves towards a long-run equilibrium with both radiative forcing and ocean heat content, while ocean heat content accumulates the deviations from atmospheric equilibrium. This model is closely related to Granger and Lee’s multicointegration model. As there are only 55 years of observations on ocean heat content, the Kalman filter is used to estimate heat content as a latent state variable, which is constrained by the available observations. This method could be applied to other climate change problems where there are only limited observations on key variables. The final model adopted relates surface temperature to the heat content of the upper 300m of the ocean. The resulting parameter estimates are closer to theoretically expected values than those of previous time series models and the estimated climate sensitivity to a doubling of carbon dioxide is 4.4 K. (c) 2005 Published by Elsevier B.V.
The influence of the possible global climate change on the properties of Mexican soils
Nikol’skii, YN Castillo-Alvarez, M Bakhlaeva, OS Roma-Calleros, XA Maslov, BS
EURASIAN SOIL SCIENCE 39:11 1164-1169
To estimate the changes in the integral fertility index of virgin soils in Mexico upon the expected global climate changes, we applied a method based on revealing the quantitative relationship between the Budyko radiation index of dryness and the modal values of the regional agrochemical properties of soils located on a nearly horizontal surface (with slope of less than 0.001) at elevations ranging from 0 to 2500 m a.s.l. The results of existing forecasts of the alteration of the global air temperature, radiation, and precipitation were also used. In the case that the carbon dioxide content is doubled in the atmosphere by the end of the 21st century, a medium and weak decrease in the soil fertility will be observed in the central (cereal) regions of Mexico; furthermore, a significant (over 20%) decrease in fertility will be observed in the tropical regions, where sugar cane is cultivated.
The elevation history of the Tibetan Plateau and its implications for the Asian monsoon
PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY 241:1 4-15
The determination of the evolving palaeoaltitude of the Tibetan Plateau, since the India-Eurasia collision underpins our understanding of how orography in central Asia affects the intensity of the monsoon and hence global climate change. Palacoaltitudes, however, cannot be measured directly and need to be inferred from proxy observations that are usually model-dependent. Differing tectonic models for the behaviour of the lithosphere during continental collision have contrasting implications for the elevation of the plateau. However, two techniques recently employed for determining palaeo-elevation are independent of tectonic models, the first involving the variation with altitude of oxygen isotopes in precipitation and the second involving the change of leaf morphology with moist static energy of the atmosphere. Elevation studies have focused on southern Tibet, largely due to the relative ease of access to the region. There is a remarkable unanimity amongst the diverse techniques applied that the altitude of the southern plateau has not significantly changed since at least the mid Miocene (ca. 15 Ma) arguing for an onset of the monsoon system during or before the early Miocene. A range of tectonic studies suggest that the northern and eastern parts of the plateau are younger geornorphological features, but there are few quantitative constraints of the timing of elevation from these regions of Tibet. Since both the elevation and the surface area of the plateau impact on atmospheric circulation, palacoaltitude studies need to be extended to chart the increasing areas of elevated land surface through time. (c) 2006 Elsevier B.V All rights reserved.
Optimal endogenous carbon taxes for electric power supply chains with power plants
Nagurney, A Liu, ZG Woolley, T
MATHEMATICAL AND COMPUTER MODELLING 44:9-10 899-916
In this paper, we develop a modeling and computational framework that allows for the determination of optimal carbon taxes applied to electric power plants in the context of electric power supply chain (generation/distribution/consumption) networks. The adoption of carbon/pollution taxes both internationally and regionally has been fueled by global climate change and fuel security risks, with a significant portion of such policy interventions directed at the electric power industry. The general framework that we develop allows for three distinct types of carbon taxation environmental policies, beginning with a completely decentralized scheme in which taxes can be applied to each individual power generator/power plant in order to guarantee that each assigned emission bound is not exceeded, to two versions of a centralized scheme, one which assumes a fixed bound over the entire electric power supply chain in terms of total carbon emissions and the other which allows the bound to be a function of the tax. The behavior of the various decision-makers in the electric power supply chain network is described, along with the three taxation schemes, and the governing equilibrium conditions, which are formulated as finite-dimensional variational inequality problems. Twelve numerical examples are presented in which the optimal carbon taxes, as well as the equilibrium electric power flows and demands, are computed. The numerical results demonstrate, as the theory predicts, that the carbon taxes achieve the desired goal, in that the imposed bounds on the carbon emissions are not exceeded. Moreover, they illustrate the spectrum of scenarios that can be explored in terms of changes in the bounds on the carbon emissions; changes in emission factors; changes in the demand price functions, etc. (c) 2006 Elsevier Ltd. All rights reserved.
Study on the trace species in the stratosphere and their impact on climate
Chen, YJ Zhou, RJ Shi, CH Bi, Y
ADVANCES IN ATMOSPHERIC SCIENCES 23:6 1020-1039
The trace gases (O-3, HCl, CH4, H2O, NO, NO2) in the stratosphere play an important role, not only in the photochemical processes in which the ozone layer destroyed, but also in the radiative processes. In this paper, we review the works on the distribution and variation of the trace gases in the stratosphere and their impact on climate, which have been carried out at the University of Science and Technology of China in the recent 20 years. The Halogen Occultation Experiment (HALOE) data were used to analyse the distribution and variation of the mixing ratio of these trace gases and the temperature trends in the stratosphere in the most recent decade. And the reanalyzed National Centers of Environmental Prediction (NCEP)/NCAR data were also used to give the temperature trends and compared with the results from HALOE data. Numerical simulations were also carried out to study the impact of ozone depletion on the global climate. In this review, the distributions of the trace gases, especially those over the Qinghai-Xizang Plateau, are discussed, and the variations and trends for the trace gases in various levels in the stratosphere have been given for the most recent decade. The temperature variation and the cooling trend obtained from HALOE data in the middle and lower stratosphere for the last 13 years are significant, which agree well with the results from NCEP/NCAR data. While the temperature trend in the upper stratosphere in this period do not seem to have much cooling. The numerical simulations show that either the Antarctic ozone hole or the ozone valley over Qinghai-Xizang Plateau affect not only the temperature and circulation in the stratosphere, but also the temperature, pressure and wind fields in the troposphere, then lead to the global climate change.
Oceanic implications for climate change policy
ENVIRONMENTAL SCIENCE & POLICY 9:7-8 595-606
Under the United Nations convention on the law of the sea (1982), each participating country maintains exclusive economic and environmental rights within the oceanic region extending 200 nm from its territorial sea, known as the exclusive economic zone (EEZ). Although the ocean within each EEZ is undoubtedly an anthropogenic CO2 sink, it has been overlooked within international climate policy. In this paper I use an area-weighted scaling argument to show that the inclusion of the EEZ CO2 sink within national carbon accounts would have significant implications in tracking national greenhouse commitments to any future climate change policy initiative. The advantages and disadvantages for inclusion of the EEZ CO2 sink into global climate change policy are also explored. The most compelling argument for including the EEZ CO2 sink is that it would enhance the equity and resources among coastal nations to combat and adapt against future climate change that will inherently impact coastal nations more so than land locked nations. If included, the funds raised could be used for either monitoring or adaptive coastal infrastructure among the most vulnerable nations. On the other hand, the EEZ anthropogenic CO2 sink cannot be directly controlled by human activities and could be used as a disincentive for some developed nations to reduce fossil-fuel related greenhouse gas emissions. This may therefore dampen efforts to ultimately reduce atmospheric greenhouse gas concentrations. In consideration of these arguments it is therefore suggested that an “EEZ clause” be added to Kyoto and any future international climate policy that explicitly excludes its use within national carbon accounts under these international climate frameworks. (c) 2006 Elsevier Ltd. All rights reserved.
Soil respiration of forest ecosystems in Japan and global implications
Lee, MS Mo, WH Koizumi, H
ECOLOGICAL RESEARCH 21:6 828-839
Within terrestrial ecosystems, soil respiration is one of the largest carbon flux components. We discuss the factors controlling soil respiration, while focusing on research conducted at the Takayama Experimental Site. Soil respiration was affected by soil temperature, soil moisture, rainfall events, typhoons, and root respiration. We consider the temporal and spatial variability of soil respiration at the Takayama Experimental Site and review the variability of annual soil respiration in Japanese forests. In the 26 compiled studies, the values of annual soil respiration ranged from 203 to 1,290 g C m(-2) year(-1), with a mean value of 669 g C m(-2) year(-1) (SD = 264, CV = 40). We note the need for more studies and data synthesis for the accurate prediction of soil respiration and soil carbon dynamics in Japanese forests. Finally, several methods for measuring soil respiration rates are compared and the implications of soil respiration rates for global climate change are discussed.
Atypical delta N-15 variations at the southern boundary of the East Pacific oxygen minimum zone over the last 50 ka
Martinez, P Lamy, F Robinson, RR Pichevin, L Billy, I
QUATERNARY SCIENCE REVIEWS 25:21-22 3017-3028
We report a nitrogen isotope record (ODP Site 1233) from the southern Chile margin at 41 degrees S. The site is located slightly south of the southern boundary of the Peru-Chile upwelling system and the associated oxygen minimum zone off Peru and northern Chile. We show that our nitrogen isotope record, from the time interval 0-50 calendar kiloyears before present (ka B.P.), bears an atypical pattern both in shape and timing when compared with records obtained from either the continental margin of the eastern Pacific or the Subantarctic Zone (SAZ) of the Southern Ocean. The delta N-15 values at Site 1233 are relatively high throughout the record, varying between 9 parts per thousand. and 13 parts per thousand. The iriajor features are a pronounced delta N-15 increase at the beginning of the deglaciation, a maximum from 19 to 10 ka B.P.; thereafter a large decrease during the early Holocene, and millenial scale oscillations showing an Antarctic timing. We propose that the record results from an amalgam of low-latitude and high-latitude processes. Low-latitude processes, including a stronger advection signal of heavy nitrates from the denitrifying zones off Peru and northern Chile, would explain the timing of the deglaciation rise and the heaviest values found over this interval, excluding the Antarctic Cold Reversal period. The overall differences between site 1233 and records from Peru and northwest American margins suggest however that the origin of the delta N-15 signal off Chile is largely controlled by hydrologic and climatic changes in the Southern Ocean. We propose that the interplay between nutrient demand in the SAZ and latitudinal shifts of hydrologic fronts controlled both the concentrations and the isotopic signature of the remaining nitrate delivered to the Chile margin. Then, the glacial surface waters of the southern Chile margin were likely lower in nitrate concentration and bear a higher delta N-15 than during interglacial periods. (c) 2006 Elsevier Ltd. All rights reserved.
Enhancement of lidar backscatters signal-to-noise ratio using empirical mode decomposition method
Wu, SH Liu, ZS Liu, BY
OPTICS COMMUNICATIONS 267:1 137-144
Lidar is being widely used to monitor meteorological parameters and atmospheric constituents. Applications include meteorology, environmental pollution, atmospheric dynamics and global climate change. Signal processing for lidar applications involve highly nonlinear models and consequently nonlinear filtering. In this paper, we applied a new method, empirical mode decomposition to the lidar signal processing. The denoising approach is done by removal of the proper intrinsic mode functions. The data from the simulation and measurements are analyzed to evaluate this method comparing with the traditional low-pass filter and the multi-pulse averaging. Results show that it is effective-and superior to the band-pass filter and the averaging method. The denoising method also allows less averaging laser shots which is important for the real-time monitoring and for the low cost laser transmitter. (c) 2006 Elsevier B.V. All rights reserved.
Low clouds and cloud immersion enhance photosynthesis in understory species of a southern Appalachian spruce-fir forest (USA)
Johnson, DM Smith, WK
AMERICAN JOURNAL OF BOTANY 93:11 1625-1632
High-attitude forests of the southern Appalachian Mountains (USA) are frequently immersed in clouds, as are many mountain forests. They may be particularly sensitive to predicted increases in cloud base altitude with global warming. However, few studies have addressed the impacts of immersion on incident sunlight and photosynthesis. Understory sunlight (photosynthetically active radiation, PAR) was measured during clear, low cloud, and cloud-immersed conditions at Mount Mitchell and Roan Mountain, NC (USA) along with accompanying photosynthesis in four representative understory species. Understory PAR was substantially less variable on immersed vs. clear days. Photosynthesis became light-saturated between similar to 100 and 400 mu mol center dot m(-2). s(-1) PAR for all species measured, corresponding closely to the sunlight environment measured during immersion. Estimated daily carbon gain was 26% greater on clear days at a more open canopy site but was 22% greater on immersed/cloudy days at a more closed canopy site. F-v/F-m (maximum photosystem II efficiency) in Abies fraseri seedlings exposed to 2.5 min full sunlight was significantly reduced (10%), indicating potential reductions in photosynthesis on clear days. In addition, photosynthesis in microsites with canopy cover was nearly 3-fold greater under immersed (2.6 mmol center dot m(-2) center dot h(-1)) vs. clear conditions (0.9 mmol center dot m(-2) center dot h(-1)). Thus, cloud immersion provided more constant PAR regimes that enhanced photosynthesis, especially in shaded microsites. Future studies are needed to predict the survival of these refugial forests under potential changes in cloud regimes.
Prognosis of the impact of global climate change on zonal ecosystems of the Volga river basin
RUSSIAN JOURNAL OF ECOLOGY 37:6 391-401
On the basis of the GISS prognostic climatic model, landscape-ecological scenarios concerning the immediate future of the region are considered in the forms of cartographic and analytical models. These scenarios predict a growing thermoarid bioclimatic trend accompanied by a general northward displacement of zonal boundaries, with corresponding acceleration of the biological cycle and increase in the productivity of boreal forests.
Evidence for carbon dioxide and moisture interactions from the leaf cell up to global scales: Perspective on human-caused climate change
Alpert, P Niyogi, D Pielke, RA Eastman, JL Xue, YK Raman, S
GLOBAL AND PLANETARY CHANGE 54:1-2 202-208
It is of utmost interest to further understand the mechanisms behind the potential interactions or synergies between the greenhouse gases (GHG) forcing(s), particularly as represented by CO2, and water processes and through different climatic scales down to the leaf scale. Toward this goal, the factor separation methodology introduced by Stein and Alpert [Stein U. and Alpert, P. 1993. Factor separation in numerical simulations, J. Atmos. Sci., 50, 2107-2115.] that allows an explicit separation of atmospheric synergies among different factors, is employed. Three independent experiments carried out recently by the present authors, are reported here, all strongly suggest the existence of a significant CO2-water synergy in all the involved scales. The experiments employed a very wide range of up-to-date atmospheric models that complement the physics currently introduced in most Global Circulation Models (GCMs) for global climate change prediction. Three modeling experiments that go from the small/micro scale (leaf scale and soil moisture) to mesoscale (land-use change and CO2 effects) and to global scale (greenhouse gases and cloudiness) all show that synergies between water and CO2 are essential in predicting carbon assimilation, minimum daily temperature and the global Earth temperature, respectively. The study also highlights the importance of including the physics associated with carbon-water synergy which is mostly unresolved in global climate models suggesting that significant carbon-water interactions are not incorporated or at least well parameterized in current climate models. Hence, there is a need for integrative climate models. As shown in earlier studies, the climate involves physical, chemical and biological processes. To only include a subset of these processes limits the skill of local, regional and global models to simulate the real climate system. In addition, our results provide explicit determination of the direct and the interactive effect of the CO2 response on the terrestrial biosphere response. There is also an implicit scale interactive effect that can be deduced from the multiscale effects discussed in the three examples. Processes at each scale-leaf, regional and global will all synergistically contribute to increase the feedbacks-which can decrease or increase the overall system’s uncertainty depending on specific case/setup and needs to be examined in future coupled, multiscale studies. (C) 2006 Elsevier B.V. All rights reserved.
Assessing Goddard Institute for Space Studies ModelE aerosol climatology using satellite and ground-based measurements: A comparison study
Liu, L Lacis, AA Carlson, BE Mishchenko, MI Cairns, B
JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES 111:D20 -
A physically based aerosol climatology is important to address questions of global climate change. We evaluate the aerosol climatology used in the GISS ModelE (Schmidt et al., 2006), by characterizing and comparing the geographic distribution and seasonal variability of aerosol optical depth (AOD) and particle size via Angstrom exponent (A) against available satellite and ground-based measurements, i.e., MODIS, MISR, POLDER, AVHRR, and AERONET data. There are a number of model parameters, particularly those related to aerosol size specification, that can be better constrained by comparison to satellite data. Our comparison shows that there are large differences in the satellite and ground-based global distributions of AOD. The differences between the observations increase for the Angstrom exponent. Given the uncertainties associated with satellite retrieval results, the agreement in the distributions of global optical depth between GCM aerosols and satellite data is qualitatively reasonable. However, the Angstrom exponent of the GCM aerosol is clearly biased low compared to satellite data, implying that the GCM aerosol sizes are overestimated. There is qualitative agreement of the ModelE aerosol single scattering albedo pi with TOMS Aerosol Index (AI) and AERONET data. The comparisons show insufficient aerosol absorption at most locations, suggesting a possible underestimation of black carbon distributions in the GCM. However, a more quantitative comparison first requires a readjustment of the GCM aerosol size specification.
Farmers’ annual activities are not tracking the speed of climate change
Menzel, A Von Vopelius, J Estrella, N Schleip, C Dose, V
CLIMATE RESEARCH 32:3 201-207
Global climate change impacts are already tracked in many physical and biological systems and they reveal a consistent picture of changes, e.g. an earlier onset of spring events in mid and higher latitudes and a lengthening of the plant growing season. However, available results are mainly based on the study of wild plants, whereas only a few studies have hinted at an earlier spring onset for agricultural plants. So far, no comprehensive study has compared phenological shifts between agricultural crops, fruit trees and wild plants. We analysed phenological time series of 93 phases in Germany (1951-2004) employing Bayesian nonparametric function estimation, and found that events related to the production of annual crops clearly differ from spring and summer events in wild plants and fruit trees. While non-farmer driven agricultural events and spring and summer growth stages of wild plants and fruit trees advanced (i.e. occurred earlier) by 4.4 to 7.1 d decade(-1), farming indicators, such as sowing and subsequent emergence of spring and winter crops, as well as harvesting, advanced by only 2.1 d decade(-1). The estimated functional behaviour and emergence of discontinuous changes are clearly different between the 2 groups. We conclude that phenological responses to temperature changes are only reflected in data of wild plants, fruit trees and those spring growth stages of winter crops and later growth stages of spring crops which are exclusively triggered by climate, while other changes due to agricultural production are subject to management practice alterations.
Determination of forest growth trends in Komi Republic (northwestern Russia): combination of tree-ring analysis and remote sensing data
Lopatin, E Kolstrom, T Spiecker, H
BOREAL ENVIRONMENT RESEARCH 11:5 341-353
It is very important to detect changes in forest productivity due to the global change on a large scale. In this work, the evolution of the vegetation in the Komi Republic (northwestern Russia) from 1982 to 2001 was analyzed using NOAA AVHRR PAL time series. A statistically significant correlation (adjusted r(2) = 0.44-0.59) between Normalized Difference Vegetation Index (NDVI) data and tree ring width (261 living trees) was identified for the territory of the Komi Republic. The increased site productivity reflected an increase of integrated NDVI values from June to August. This allows NDVI to be used as a proxy for estimation of forest growth trends for the recent decades. A positive and significant trend in NDVI data was identified from 1982 to 2001, coinciding with an increase in site productivity in the study area. The decrease in precipitations coincided with an increase in site productivity (highest r(2) was 0.71). The increase in productivity reflected in NDVI data is maximal on the sites with increased temperature and decreased precipitations. In the Komi Republic the distribution of the trends in NDVI data changes on the south-west to north-east gradient. NDVI data could be used to increase spatial resolution of tree ring width series. Taking into account the relatively small role of human activity in the Komi Republic compared with Europe, the site productivity during recent decades also increased in relatively untouched forests.
Eastern Pacific cooling and Atlantic overturning circulation during the last deglaciation
Kienast, M Kienast, SS Calvert, SE Eglinton, TI Mollenhauer, G Francois, R Mix, AC
NATURE 443:7113 846-849
Surface ocean conditions in the equatorial Pacific Ocean could hold the clue to whether millennial-scale global climate change during glacial times was initiated through tropical ocean - atmosphere feedbacks or by changes in the Atlantic thermohaline circulation(1). North Atlantic cold periods during Heinrich events and millennial-scale cold events (stadials) have been linked with climatic changes in the tropical Atlantic Ocean and South America(2-4), as well as the Indian and East Asian monsoon systems(5,6), but not with tropical Pacific sea surface temperatures(7). Here we present a high-resolution record of sea surface temperatures in the eastern tropical Pacific derived from alkenone unsaturation measurements. Our data show a temperature drop of 1 degrees C, synchronous ( within dating uncertainties) with the shutdown of the Atlantic meridional overturning circulation during Heinrich event 1, and a smaller temperature drop of 0.5 degrees C synchronous with the smaller reduction in the overturning circulation during the Younger Dryas event. Both cold events coincide with maxima in surface ocean productivity as inferred from Th-230-normalized carbon burial fluxes, suggesting increased upwelling at the time. From the concurrence of equatorial Pacific cooling with the two North Atlantic cold periods during deglaciation, we conclude that these millennial-scale climate changes were probably driven by a reorganization of the oceans’ thermohaline circulation, although possibly amplified by tropical ocean - atmosphere interaction as suggested before(8).
Predicted climate change alters the indirect effect of predators on an ecosystem process
Lensing, JR Wise, DH
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA 103:42 15502-15505
Changes in rainfall predicted to occur with global climate change will likely alter rates of leaf-litter decomposition through direct effects on primary decomposers. In a field experiment replicated at two sites, we show that altered rainfall may also change how cascading trophic interactions initiated by arthropod predators in the leaf litter indirectly influence litter decomposition. On the drier site there was no interaction between rainfall and the indirect effect of predators on decomposition. In contrast, on the moister site spiders accelerated the disappearance rate of deciduous leaf litter under low rainfall, but had no, or possibly a negative, indirect effect under high rainfall. Thus, changes resulting from the more intense hydrological cycle expected to occur with climate change will likely influence how predators indirectly affect an essential ecosystem process.
Relationship between climate, pollen concentrations of Ambrosia and medical consultations for allergic rhinitis in Montreal, 1994-2002
Breton, MC Garneau, M Fortier, I Guay, F Louis, J
SCIENCE OF THE TOTAL ENVIRONMENT 370:1 39-50
The aim of this study is to evaluate the influence of meteorological factors on Ambrosia pollen concentrations and its impact on medical consultations for allergic rhinitis of residents from various socio-economic levels in Montreal (Quebec, Canada) between 1994 and 2002. The study was conducted to recognize the sensitivity of pollen productivity to daily climate variability in order to estimate the consequences on human health vulnerability in the context of global climate change. Information related to medical consultations for allergic rhinitis due to pollen comes from the Quebec Health Insurance Board (Regie de l’assurance-maladie du Quebec). Ambrosia pollen concentration was measured by the Aerobiology Research Laboratories (Nepean, Ontario). Daily temperature (maximum, minimum, and mean) and precipitation data were obtained from the Meteorological Service of Canada. Socio-economic data come from the 1996 and 2001 census data of Statistics Canada. Between 1994 and 2002, during the Ambrosia pollen season, 7667 consultations for allergic rhinitis due to pollen were recorded. We found a significant association between the number of medical consultations and pollen levels. Significant associations were detected for over-consultation the day of exposure, 1, 2, 3 and 5 days after exposure to high levels of pollen. The consultation rate is higher from low-income residents (3.10 consultations per 10,000 inhabitants) than for high-income (1.65 consultations per 10,000 inhabitants). Considering the demonstrated impact of pollen levels on health, it has become critical to ensure adequate monitoring of Ambrosia and its meteorological sensivity in the context of the anticipated climate change and its potential consequences on human health. (c) 2006 Elsevier B.V. All rights reserved.
Adverse high temperature effects on pollen viability, seed-set, seed yield and harvest index of grain-sorghum [Sorghum bicolor (L.) Moench] are more severe at elevated carbon dioxide due to higher tissue temperatures
Prasad, PVV Boote, KJ Allen, LH
AGRICULTURAL AND FOREST METEOROLOGY 139:3-4 237-251
Global climate change, especially, increases in carbon dioxide (CO2) concentration and the associated increases in temperature will have significant impact on the crop production. Grain-sorghum [Sorghum bicolor (L.) Moench] cultivar DeKalb 28E was grown at daytime maximum/nighttime minimum temperature regimes of 32/22, 36/26, 40/30 and 44/34 degrees C at ambient (350 mu mol CO2 mol(-1)) and elevated (700 mu mol CO2 mol(-1)) CO2 from emergence to maturity in controlled environments to quantify the effects of temperature and CO2 on the reproductive processes and yield. Growth temperatures of 40/30 and 44/34 degrees C inhibited particle emergence. Growth temperatures >= 36/26 degrees C significantly decreased pollen production, pollen viability, seed-set, seed yield and harvest index when compared to 32/22 degrees C. Percentage decreases in pollen viability, seed-set, seed yield and harvest index due to elevated temperature were greater at elevated CO2 when compared with ambient CO2. Elevated CO2 increased seed yield (26%) at 32/22 degrees C, but decreased seed yield (10%) at 36/26 degrees C. At high temperatures, elevated CO2 increased vegetative growth but not seed yield, thus, leading to decreased harvest index. We conclude that the adverse effects of elevated temperature on reproductive processes and yield of grain-sorghum were more severe at elevated CO2 than at ambient CO2; and the beneficial effects of elevated CO2 decreased with increasing temperature. The adverse temperature sensitivity of reproductive processes and yield at elevated CO2 was attributed to higher canopy foliage and seed temperatures. (c) 2006 Elsevier B.V. All rights reserved.
Aquatic plants diversity in arid zones of Northwest China: patterns, threats and conservation
Li, ZQ Yu, D Xiong, W Wang, D
BIODIVERSITY AND CONSERVATION 15:11 3417-3444
We investigated aquatic plant diversity by conducting the field investigation and collecting the published data in the arid regions of Northwest China. Two hundred and twenty four taxa of vascular aquatic plants representing 64 genera and 34 families occur in this area, 8.48% of which are endemic. Among these, 1 genus and 6 species were new state records and 1 family, 9 genera and 29 species were new area records. Typhaceae, Potamogetonaceae, Juncaginaceae and Haloragaceae were the most frequent families (considering relative frequency of occurrence), whereas Cyperaceae, Potamogetonaceae and Ranuncnlaceae are the most species-rich. The most frequent genera were Typha, Potamogeton, and Triglochin, and the most species-rich were Potamogeton, Eleocharis and Scirpus. The most frequent species are Triglochin palustre, Myriophyllum spicatum, Potamogeton pectinatus and Typha angustifolia. Aquatic plants diversity is distributed unevenly in the region. The maximum species occurs in Dzungarian basin while the least species in Hexi corridor. The aquatic flora in arid zone of China is not distinctive although some endemic species are found, most species are widely distributed. Local aquatic plants diversity can be influenced by many factors such as hydrological alteration, habitat loss, over-grazing, high human population pressure, global climate change, an inappropriate economic development policy. Among them, the largest threat to aquatic plants biodiversity may be habitat loss due to hydrological alteration. In order to conserve the aquatic plants biological resources and biodiversity in this region, some strategies and measures must be suggested including strengthening scientific research and biodiversity education in the local people, balancing economic development and ecological conservation, and enhancing governmental assistance and subsidy to the local residents.
Ecological niche modelling and prioritizing areas for species reintroductions
Martinez-Meyer, E Peterson, AT Servin, JI Kiff, LF
ORYX 40:4 411-418
Species reintroduction programmes, in prioritizing areas for reintroductions, have traditionally used tools that include measures of habitat suitability and evaluations of area requirements for viable populations. Here we add two tools to this approach: evaluation of ecological requirements of species and evaluation of future suitability for species facing changing climates. We demonstrate this approach with two species for which reintroduction programmes are in the planning stages in Mexico: California condor Gymnogyps californianns and Mexican wolf Canis lupus baileyi. For the condor, we identify three areas clustered in the Sierra San Pedro Martir, Baja California; for the wolf, we identify a string of suitable sites along the Sierra Madre Occidental of western Mexico. We discuss the limitations of this approach, identifying ways in which the models illustrated could be made more realistic and directly useful to reintroduction programmes.
Integration of ice-core, marine and terrestrial records for the Australian Last Glacial Maximum and Termination: a contribution from the OZ INTIMATE group
Turney, CSM Haberle, S Fink, D Kershaw, AP Barbetti, M Barrows, TT Black, M Cohen, T Correge, T Hesse, PP Hua, Q Johnston, R Morgan, V Moss, P Nanson, G Van Ommen, T Rule, S Williams, NJ Zhao, JX D’Costa, D Feng, YX Gagan, MK Mooney, S Xia, Q
JOURNAL OF QUATERNARY SCIENCE 21:7 751-761
The degree to which Southern Hemisphere climatic changes during the end of the last glacial period and early Holocene (30-8 ka) were influenced or initiated by events occurring in the high latitudes of the Northern Hemisphere is a complex issue. There is conflicting evidence for the degree of hemispheric ‘teleconnection’ and an unresolved debate as to the principle forcing mechanism(s). The available hypotheses are difficult to test robustly, however, because the few detailed palaeoclimatic records in the Southern Hemisphere are widely dispersed and lack duplication. Here we present climatic and environmental reconstructions from across Australia, a key region of the Southern Hemisphere because of the range of environments it covers and the potentially important role regional atmospheric and oceanic controls play in global climate change. We identify a general scheme of events for the end of the last glacial period and early Holocene but a detailed reconstruction proved problematic. Significant progress in climate quantification and geochronological control is now urgently required to robustly investigate change through this period. Copyright (c) 2006 John Wiley & Sons, Ltd.
Soil carbon turnover in the McMurdo Dry Valleys, Antarctica
Barrett, JE Virginia, RA Parsons, AN Wall, DH
SOIL BIOLOGY & BIOCHEMISTRY 38:10 3065-3082
Terrestrial ecosystems of the Antarctic Dry Valleys are among the most inhospitable soil environments on Earth due to climate and substrate limitations over biota. These ecosystems present a challenge to understanding controls over carbon (C) cycling because likely sources of organic matter are 10(2)-10(4) yrs old and in situ soil respiration is typically less than 1.0 mu mol CO2 m(-2) s(-1). In this paper we describe an analytical approach to characterize kinetic pools of labile and recalcitrant soil C, and estimate C turnover in dry valley soils based upon these descriptions. Rate parameters for C turnover were derived from laboratory incubations conducted under a range of soil moistures and temperatures. We developed a C flux and reservoir model using these rate parameters along with published estimates of internal C transformations in soil microbial ecosystems, and a previously described primary production (NPP) model for Antarctic endolithic communities. We found that decomposition in 120 d incubations was well described by double-exponential rate kinetics, and that temperature, moisture and substrate availability significantly influenced observed rates of soil respiration. Simulations of soil C cycling based upon these parameters produced initially high rates of soil respiration following inputs of external organic matter, with mean residence times for C of 10-60 yrs. Soil organic C content equilibrated at 44-140% of observed levels within 1000 yrs. Simulations of equilibrium C were sensitive to NPP, microbial efficiency (Y), and the distribution of C inputs into labile and passive pools, indicating that more thorough investigation of microbial influence over the C cycle in dry valley soils is necessary. (c) 2006 Elsevier Ltd. All rights reserved.
Technology options for capturing CO2
Elwell, LC Grant, WS
POWER 150:8 60-+
Concerns about global climate change have prompted interest in reducing or eliminating the carbon dioxide (CO2) emissions of fossil fuel-fired power plants. Here’s a guide to the technology and economics of three CO2 capture methods: postcombustion separation Of CO2 from flue gas (applicable to existing plants), and oxygen-fired combustion and precombustion capture (suitable for new coal-fired capacity, including IGCC plants).
Lichen flora around the Korean Antarctic Scientific Station, King George Island, Antarctic
Kim, JH Ahn, IY Hong, SG Andreev, M Lim, KM Oh, MJ Koh, YJ Hur, JS
JOURNAL OF MICROBIOLOGY 44:5 480-491
As part of the long-term monitoring projects on Antarctic terrestrial vegetation in relation to global climate change, a lichen floristical survey was conducted around the Korean Antarctic Station (King Sejong Station), which is located on Barton Peninsula, King George Island, in January and February of 2006. Two hundred and twenty-five lichen specimens were collected and sixty-two lichen species in 38 genera were identified by morphological characteristics, chemical constituents, TLC analysis and ITS nucleotide sequence analysis.
European phenological response to climate change matches the warming pattern
Menzel, A Sparks, TH Estrella, N Koch, E Aasa, A Ahas, R Alm-Kubler, K Bissolli, P Braslavska, O Briede, A Chmielewski, FM Crepinsek, Z Curnel, Y Dahl, A Defila, C Donnelly, A Filella, Y Jatcza, K Mage, F Mestre, A Nordli, O Penuelas, J Pirinen, P Remisova, V Scheifinger, H Striz, M Susnik, A Van Vliet, AJH Wielgolaski, FE Zach, S Zust, A
GLOBAL CHANGE BIOLOGY 12:10 1969-1976
Global climate change impacts can already be tracked in many physical and biological systems; in particular, terrestrial ecosystems provide a consistent picture of observed changes. One of the preferred indicators is phenology, the science of natural recurring events, as their recorded dates provide a high-temporal resolution of ongoing changes. Thus, numerous analyses have demonstrated an earlier onset of spring events for mid and higher latitudes and a lengthening of the growing season. However, published single-site or single-species studies are particularly open to suspicion of being biased towards predominantly reporting climate change-induced impacts. No comprehensive study or meta-analysis has so far examined the possible lack of evidence for changes or shifts at sites where no temperature change is observed. We used an enormous systematic phenological network data set of more than 125 000 observational series of 542 plant and 19 animal species in 21 European countries (1971-2000). Our results showed that 78% of all leafing, flowering and fruiting records advanced (30% significantly) and only 3% were significantly delayed, whereas the signal of leaf colouring/fall is ambiguous. We conclude that previously published results of phenological changes were not biased by reporting or publication predisposition: the average advance of spring/summer was 2.5 days decade(-1) in Europe. Our analysis of 254 mean national time series undoubtedly demonstrates that species’ phenology is responsive to temperature of the preceding months (mean advance of spring/summer by 2.5 days degrees C-1, delay of leaf colouring and fall by 1.0 day degrees C-1). The pattern of observed change in spring efficiently matches measured national warming across 19 European countries (correlation coefficient r=-0.69, P < 0.001).
The northern geographic range limit of the intertidal limpet Collisella scabra: a test of performance, recruitment, and temperature hypotheses
ECOGRAPHY 29:5 709-720
A decline in abundance towards a species’ range boundary is often interpreted as evidence of a decline in individual success, and is usually assumed to reflect a decline in suitable environmental conditions. Gradual declines towards high latitude range boundaries are frequently attributed to limitations on organismal tolerance of cold temperature. Rarely have these two assumptions been empirically tested. The intertidal gastropod Collisella scabra declines monotonically in abundance from 435 to < 1 m(-2) over the northern 300 km of its geographic distribution. I examined temperature, adult performance (survival, growth, reproduction), and recruitment at five locations in this region of decline. Mortality ranged from 4.9 to 11.2% per month, but was highest at the lowest latitude study site. Growth rates ranged from 0 to 5.2 mm yr(-1), but were generally lower at lower latitude sites. Gonad development was high in the three populations examined, but the possibility of infrequent spawning at high latitude sites could not be excluded. Finally, a comparison of performance differences among populations with temperature revealed clear effects of temperature on both growth and mortality; however, the patterns were not consistent with a hypothesis of cold stress at the range boundary. Overall there was little evidence for either reduced performance or increasing cold stress in low density high latitude populations. Over the same 300 km, recruitment declined monotonically from a mean of six recruits per 625 cm(2) to less than one; suggesting that limitations on recruitment, rather that adult performance, are responsible for low abundance in marginal populations. Several hypotheses for the decline in recruitment are discussed in the paper and the most likely explanation appears to be an increase in the distance between populations at the range margin, reducing the chances that dispersing larvae find suitable habitat for settlement.
Seasonal resource availability and use by an endangered tropical mycophagous marsupial
Abell, SE Gadek, PA Pearce, CA Congdon, BC
BIOLOGICAL CONSERVATION 132:4 533-540
This study highlights the importance of considering how seasonality of rainfall affects availability of resources and consequently species distributions within tropical ecosystems. The endangered northern bettong, Bettongia tropica Wakefield is thought to be restricted to habitats where seasonal availability of hypogeous fungi, their principal food resource, remains high. To test this hypothesis fungal abundance was quantified in the early wet, late wet, early dry and late dry seasons within known bettong habitat. A relationship was found between precipitation and fungal availability, with the abundance of hypogeous fungi being significantly lower in the late dry season. Fungal availability correlated strongly with the seasonal rainfall pattern determined from 74-year monthly means. This contrasts with a previous study where mycophagy, measured by faecal analysis, remained high across seasons presumably because of aseasonal rainfall during that study period. Alloteropsis semialata R.Br. (cockatoo grass) use by bettongs increased significantly during the period of low fungal availability. This suggests that the importance of cockatoo grass as an alternative food resource during annual and extended dry periods has previously been underestimated. With the frequency and intensity of drought expected to increase with global climate change, these findings have significant implications for bettong management. The important and possibly equivalent dependence of B. tropica on both hypogeous fungi and A. semialata helps to explain their habitat preference and identifies this species as a true ecotonal specialist. (c) 2006 Elsevier Ltd. All rights reserved.
The PACE monitoring strategy: A concept for permafrost research in Qinghai-Tibet
King, L Herz, T Hartmann, H Hof, R Jiang, T Ke, C Wei, Z Liu, J Yi, C
QUATERNARY INTERNATIONAL 154: 149-157
Permafrost has been identified as one of six cryospheric indicators for global climate change within the monitoring framework of the World Meteorological Organisations Global Climate Observing System (GCOS). Vast areas of the Tibetan Plateau are underlain by predominantly warm permafrost, which is actually degrading due to a rise in mean surface temperatures caused by global warming. Because of the important role of surface temperature variations on the Tibetan Plateau for the onset and characteristic of the monsoon circulation over south-east Asia, it becomes evident that a consistent climate monitoring strategy in the region is urgently required. As permafrost reacts sensitively to changes in surface temperature, it is considered as a key variable in such a regional climate monitoring system. The Permafrost and Climate in Europe (PACE) project developed standardised methods for the monitoring of permafrost temperatures and distribution in European mountains, which are in good agreement with the site selection criteria of the GCOS Global Terrestrial Network-Permafrost (GTN-P). Following the PACE monitoring strategy, an international project “Permafrost and Climate in Tibet” is proposed. (c) 2006 Elsevier Ltd and INQUA. All rights reserved.
The impact of increased environmental stochasticity due to climate change on the dynamics of asiatic wild ass
Saltz, D Rubenstein, DI White, GC
CONSERVATION BIOLOGY 20:5 1402-1409
Theory proposes that increased environmental stochasticity negatively impacts population viability. Thus, in addition to the directional changes predicted for weather parameters under global climate change (GCC), the increase in variance of these parameters may also have a negative effect on biodiversity. As a case study, we assessed the impact of interannual variance in precipitation on the viability of an Asiatic wild ass (Equus hemionus) population reintroduced in Makhtesh Ramon Nature Reserve, Israel. We monitored the population from 1985 to 1999 to determine what environmental factors affect reproductive success. Annual precipitation during the year before conception, drought conditions during gestation, and population size determined reproductive success. We used the parameters derived from this model to assess population performance under various scenarios in a Leslie matrix type model with demographic and environmental stochasticity. Specifically, we used a change in the precipitation regime in our study area to formulate a GCC scenario and compared the simulated dynamics of the population with a no-change scenario. The coefficient of variation in population size under the global change scenario was 30% higher than under the no-change scenario. Minor die-offs (>= 15%) following droughts increased extinction probability nearly 10-fold. Our results support the idea that an increase in environmental stochasticity due to GCC may, in itself, pose a significant threat to biodiversity.
Impact of electric power generation on green house gas emissions in Europe: Russia, Greece, Italy and views of the EU Power Plant Supply Industry - a critical analysis
INTERNATIONAL JOURNAL OF ELECTRICAL POWER & ENERGY SYSTEMS 28:8 548-564
This paper analyses the impact of electric power generation on greenhouse gas emissions in Europe (including the Asian part of Russia) with reference to Russia, Greece, Italy, and views of the EU power plant supply industry in respect of the Kyoto protocol. The outlook of power industry development in Russia in the 21st century is first considered and its impact on Russia’s greenhouse gas emissions is examined. Forecasts for developing Russia’s economy and electric power industry in the first half of the 21st century are presented. Possible structural change in the electric power industry in Russia together with dynamic changes Of CO2 emissions from fuel combustion in power plants are examined. It is shown that CO2 emissions from fuel combustion at power plants in Russia may increase 2.7-fold in 50 years. Calculations depict that specific CO2 emissions in Asian Russia exceed greatly that of the European part. It then reviews measures to limit greenhouse gas emissions in Greece. Impact of the currently adopted measures and initiatives to reduce emissions in the Greek energy system for the period up to 2030 is discussed with emphasis on the current decade. Under the scenario for environmental policy, the additional commitments and measures to limit CO2 emissions towards the Kyoto targets are discussed. The paper summarizes a possible Italian strategy for implementing Kyoto protocol mechanisms to meet commitments of the EU Emission Trading Draft Directive, the Italian strategy in the Ministerial documents, and final considerations. It then examines clean power generation technology for the 21st Century and gives a perspective from the EU power plant supply industry. A perspective is presented with respect to impact of global climate change on product development strategy. Fossil fuel based power generation technologies will continue to play an important part of the energy mix in the foreseeable future and different parts of the world will require different technologies to meet their local specific requirements. It will be necessary to continue to develop clean technologies and to promote their use world-wide. (c) 2006 Elsevier Ltd. All rights reserved.
Correlations between carbon dioxide emissions and carbon contents of fuels
ENERGY SOURCES PART B-ECONOMICS PLANNING AND POLICY 1:4 421-427
The gases (they consist of three or more atoms) with higher heat capacities than those of O-2 and N-2 cause greenhouse effect. Carbon dioxide (CO2) is main greenhouse gas associated with global climate change. Collectively, they are projected to contribute, directly, about as much too potential global warming over the next 60 years as CO2. At the present time, coal is responsible for 30-40% of world CO2 emissions from fossil fuels. There were a higher correlation between amount of carbon dioxide emission and percentage of carbon in the fuel for all equations. The squares of correlation coefficients were 0.9999, 0.9978, and 0.9995.
Invasive grass reduces aboveground carbon stocks in shrublands of the Western US
Bradley, BA Houghtonw, RA Mustard, JF Hamburg, SP
GLOBAL CHANGE BIOLOGY 12:10 1815-1822
Understanding the terrestrial carbon budget, in particular the strength of the terrestrial carbon sink, is important in the context of global climate change. Considerable attention has been given to woody encroachment in the western US and the role it might play as a carbon sink; however, in many parts of the western US the reverse process is also occurring. The conversion of woody shrublands to annual grasslands involves the invasion of non-native cheatgrass (Bromus tectorum) which in turn leads to increased frequency and extent of fires. We compared carbon storage in adjacent plots of invasive grassland and native shrubland. We scaled-up the impact of this ecosystem shift using regional maps of the current invasion and of the risk of future invasion. The expansion of cheatgrass within the Great Basin has released an estimated 8 +/- 3 Tg C to the atmosphere, and will likely release another 50 +/- 20 Tg C in the coming decades. This ecosystem conversion has changed portions of the western US from a carbon sink to a source, making previous estimates of a western carbon sink almost certainly spurious. The growing importance of invasive species in driving land cover changes may substantially change future estimates of US terrestrial carbon storage.
The human role in changing river channels
GEOMORPHOLOGY 79:3-4 172-191
Direct consequences of the human role, where human activity affects river channels through engineering works including channelization, dam construction, diversion and culverting, have been long recognised [Marsh, G.P., 1864. Man and Nature or Physical Geography as Modified by Human Action. Charles Scribner, New York; Thomas Jr., W.L., (ed.) 1956. Man’s Role in Changing the Face of the Earth. Chicago, University of Chicago Press, Chicago.]. The less obvious indirect effects of point and reach changes occurring downstream and throughout the basin, however, are much more recently appreciated, dating from key contributions by Strahler [Strahler, A.N., 1956. The nature of induced erosion and aggradation. In W. L. Thomas (Ed.), Man’s Role in Changing the Face of the Earth. University of Chicago Press, Chicago, 621-638.], Wohnan [Wolman, M.G., 1967. A cycle of sedimentation and erosion in urban river channels. Geografiska Annaler 49A, 385-95.], Schumm [Schumm, S.A., 1969. River metamorphosis. Proceedings American Society of Civil Engineers, Journal Hydraulics Division 95, 255-73.], and Graf [Graf, W.L., 1977. The rate law in fluvial geomorphology. American Journal of Science, 277, 178-191.]. These are complemented by effects of alterations of land use, such as deforestation, intensive agriculture and incidence of fire, with the most extreme effects produced by building activity and urbanisation. Changing river channels are most evident in the channel cross-section where changes of size, shape and composition are now well-established, with up to tenfold increases or decreases illustrated by results from more than 200 world studies. In addition the overall channel planform, the network and the ecology have changed. Specific terns have become associated with changing river channels including enlargement, shrinkage and metamorphosis. Although the scope of adjustment has been established, it has not always been possible to predict what will happen in a particular location, because of complex response and contingency. The ways in which changes in cross-section relate to reach and network changes are less clear, despite investigations showing the distribution of changes along segmented channels. When considering the human role in relation to changing river channels, at least five challenges persist. First, because prediction of the nature and amount of likely change at a particular location is not certain, and because the contrasting responses of humid and arid systems needs to be considered, modelling is required to reduce uncertainty, as was first emphasised by Burkham [Burkham, D.E., 1981. Uncertainties resulting from changes in river form. American Society Civil Engineers Proceedings, Journal Hydraulics Division 107, 593-610.]. Second, feedback effects incorporated within the relationship between changes at channel, reach and network scales can have considerable implications, especially because changes now evident may have occurred, or have been initiated, under different environmental conditions. Third, consideration of global climate change is imperative when considering channel sensitivity and responses to threshold conditions. Fourth, channel design involving geomorphology should now be an integral part of restoration procedures. This requires, fifthly, greater awareness of different cultures as a basis for understanding constraints imposed by legislative frameworks. Better understanding of the ways in which the perception of the human role in changing river channels varies with culture as well as varying over time should enhance application of design for river channel landscapes. (c) 2006 Elsevier B.V. All rights reserved.
The economic impact of global climate change on Mediterranean rangeland ecosystems: A Space-for-Time approach
Fleischer, A Sternberg, M
ECOLOGICAL ECONOMICS 59:3 287-295
Global Climate Change (GCC) can bring about changes in ecosystems and consequently in their services value. Here we show that the urban population in Israel values the green landscape of rangelands in the mesic Mediterranean climate region and is willing to pay for preserving it in light of the expected increasing aridity conditions in this region. Their valuation of the landscape is higher than that of the grazing services these rangelands provide for livestock growers. These results stem from a Time-for-Space approach with which we were able to measure changes in biomass production and rainfall at four experimental sites along an aridity gradient. (c) 2005 Elsevier B.V. All rights reserved.
A pilot test of a new stated preference valuation method: Continuous attribute-based stated choice
Ready, R Fisher, A Guignet, D Stedman, R Wang, JC
ECOLOGICAL ECONOMICS 59:3 247-255
A new stated preference nonmarket valuation technique is developed. In an interactive computerized survey, respondents move continuous sliders to vary levels of environmental attributes. The total cost of the combination of attributes is calculated according to a preprogrammed cost function, continuously updated and displayed as respondents move the sliders. Each registered choice reveals the respondent’s marginal willingness to pay for each of the attributes. The method is tested in a museum exhibit on global climate change. Two construct validity tests were conducted. Responses are sensitive to the shape of the cost function in ways that are consistent with expectations based on economic theory. implied marginal willingness to pay values were similar to those estimated using a more traditional paired comparisons stated choice format. However, responses showed range effects that indicate potential cognitive biases. (c) 2005 Elsevier B.V. All rights reserved
A phyloclimatic study of Cyclamen
Yesson, C Culham, A
BMC EVOLUTIONARY BIOLOGY 6: -
Background: The impact of global climate change on plant distribution, speciation and extinction is of current concern. Examining species climatic preferences via bioclimatic niche modelling is a key tool to study this impact. There is an established link between bioclimatic niche models and phylogenetic diversification. A next step is to examine future distribution predictions from a phylogenetic perspective. We present such a study using Cyclamen (Myrsinaceae), a group which demonstrates morphological and phenological adaptations to its seasonal Mediterranean-type climate. How will the predicted climate change affect future distribution of this popular genus of garden plants? Results: We demonstrate phylogenetic structure for some climatic characteristics, and show that most Cyclamen have distinct climatic niches, with the exception of several wide-ranging, geographically expansive, species. We reconstruct climate preferences for hypothetical ancestral Cyclamen. The ancestral Cyclamen lineage has a preference for the seasonal Mediterranean climate characteristic of dry summers and wet winters. Future bioclimatic niches, based on BIOCLIM and Maxent models, are examined with reference to a future climate scenario for the 2050s. Over the next 50 years we predict a northward shift in the area of climatic suitability, with many areas of current distribution becoming climatically unsuitable. The area of climatic suitability for every Cyclamen species is predicted to decrease. For many species, there may be no areas with a suitable climate regardless of dispersal ability, these species are considered to be at high risk of extinction. This risk is examined from a phylogenetic perspective. Conclusion: Examining bioclimatic niches from a phylogenetic perspective permits novel interpretations of these models. In particular, reconstruction of ancestral niches can provide testable hypothesis about the historical development of lineages. In the future we can expect a northwards shift in climatic suitability for the genus Cyclamen. If this proves to be the case then dispersal is the best chance of survival, which seems highly unlikely for ant-dispersed Cyclamen. Human-assisted establishment of Cyclamen species well outside their native ranges offers hope and could provide the only means of dispersal to potentially suitable future environments. Even without human intervention the phylogenetic perspective demonstrates that major lineages could survive climate change even if many species are lost.
Increase of alien and C-4 plant species in annual river bank vegetation of the River Rhine
PHYTOCOENOLOGIA 36:3 393-402
Recent and historic releves of the annual river bank vegetation (Polygono brittingeri-Chenopodictum rubri, Chenopodium rubrum subassociation) of the middle and lower River Rhine (Germany) were evaluated with regard to their representation of alien and C, plant species. The releves evaluated covered a period of more than 50 years from the second half of the 20,h to the beginning of the 21(st) century. There was a distinct increase in the proportion of alien and C, plant species: The mean percentage of post-1492 aliens (neophytes) increased from 9.9% in 1964 to 27.5% in 2002. In the same period, the mean percentage of C-4 plants increased from 4.4% to 11.5%. In 1998 - 2002 99 alien plant species were recorded in the annual sand and gravel bank vegetation of the study area. Possible reasons for the increase of alien and C, plants may include increased trade activities and increased temperatures due to global climate change.
Conserving and increasing biodiversity in the large-scale, intensive farming systems of the Western Cape, South Africa
SOUTH AFRICAN JOURNAL OF SCIENCE 102:9-10 375-378
The Convention on Biological Diversity, adopted in 1992 in Nairobi and signed by many states, including South Africa, at the United Nations Conference on Environment and Development in Rio de Janeiro later that year, urges nations to conserve biological diversity. This places a special responsibility on farmers, who own most of the land. Yet agricultural practices usually aim at simplifying ecosystems in favour of the crops (and animals) that are produced. In the Western Cape province of South Africa, this process has resulted in extensive monocultures of wheat, grapevines and fruit trees. The questions arise: should farmers bring more biodiversity back into these systems and, if so, how can they do it? Apart from the moral obligation to do so, perceived benefits include the possibility of greater economic and ecological stability, especially under conditions of global climate change; enhanced aesthetic appeal and greater acceptance of farming practices by the public in general and purchasers of farm produce in particular. Possible disadvantages are short-term losses in productivity and profitability. Measures that will contribute towards increasing biodiversity include: intercropping; the planting and maintenance of shelter belts, buffer strips and natural corridors; retaining riparian and other areas of high value natural vegetation; making dams attractive to wildlife; reducing the impact of pesticides; educating farmers and farm workers about the values of biodiversity conservation; and providing financial incentives to landowners for biodiversity conservation. An overview is provided in this paper of current international and national biodiversity conservation policies and programmes and some of the local initiatives that are active in the Western Cape to protect and re-establish biodiversity.
Extreme precipitation over the Maritime Alps and associated weather regimes simulated by a regional climate model: Present-day and future climate scenarios
Boroneant, C Plaut, G Giorgi, F Bi, X
THEORETICAL AND APPLIED CLIMATOLOGY 86:1-4 81-99
We use the regional climate model RegCM nested within time-slice atmospheric general circulation model experiments to investigate the possible changes of intense and extreme precipitation over the French Maritime Alps in response to global climate change. This is a region with complex orography where heavy and/or extended precipitation episodes induced catastrophic floods during the last decades. Output from a 30-year simulation of present-day climate (1961-1990) is first analysed and compared with NCEP reanalysed 700 CehPa geopotential heights (Z700) and daily precipitation observations from the Alpine Precipitation Climatology (1966-1999). Two simulations under forcing from the A2 and B2 IPCC emission scenarios for the period 2071-2100 are used to investigate projected changes in extreme precipitation for our region of interest. In general, the model overestimates the annual cycle of precipitation. The climate change projections show some increase of precipitation, mostly outside the warm period for the B2 scenario, and some increase in the variability of the annual precipitation totals for the A2 scenario. The model reproduces the main observed patterns of the spatial leading EOFs in the Z700 field over the Atlantic-European domain. The simulated large scale circulation (LSC) variability does not differ significantly from that of the reanalysis data provided the EOFs are computed on the same domain. Two similar clusters of LSC corresponding to heavy precipitation days were identified for both simulated and observed data and their patterns do not change significantly in the climate change scenarios. The analysis of frequency histograms of extreme indices shows that the control simulation systematically underestimates the observed heavy precipitation expressed as the 90(th) percentile of rainday amounts in all seasons except summer and better reproduces the greatest 5-day precipitation accumulation. The main hydrological changes projected for the Maritime Alps consist of an increase of most intense wet spell precipitation during winters for both scenarios and during autumn for the B2 scenario. Case studies of heavy precipitation events show that the RegCM is capable to reproduce the physical mechanisms responsible for heavy precipitation over our region of interest.
A synthesis of bentho-pelagic coupling on the Antarctic shelf: Food banks, ecosystem inertia and global climate change
Smith, CR Mincks, S DeMaster, DJ
DEEP-SEA RESEARCH PART II-TOPICAL STUDIES IN OCEANOGRAPHY 53:8-10 875-894
The Antarctic continental shelf is large, deep (500-1000 m), and characterized by extreme seasonality in sea-ice cover and primary production. Intense seasonality and short pelagic foodwebs on the Antarctic shelf may favor strong benthopelagic coupling, whereas unusual water depth combined with complex topography and circulation could cause such coupling to be weak. Here, we address six questions regarding the nature and strength of coupling between benthic and water-column processes on the continental shelf surrounding Antarctica. We find that water-column production is transmitted to the shelf floor in intense pulses of particulate organic matter, although these pulses are often difficult to correlate with local phytoplankton blooms or sea-ice conditions. On regional scales, benthic habitat variability resulting from substrate type, current regime, and iceberg scour often may obscure the imprint of water-column productivity on the seafloor. However, within a single habitat type, i.e. the muddy sediments that characterize much of the deep Antarctic shelf, macrobenthic biomass appears to be correlated with regional primary production and sea-ice duration. Over annual timescales, many benthic ecological processes were initially expected to vary in phase with the extraordinary boom/bust cycle of production in the water column. However, numerous processes, including sediment respiration, deposit feeding, larval development, and recruitment, often are poorly coupled to the summer bloom season. Several integrative, time-series studies on the Antarctic shelf suggest that this lack of phasing may result in part from the accumulation of a persistent sediment food bank that buffers the benthic ecosystem from the seasonal variability of the water column. As a consequence, a variety of benthic parameters (e.g., sediment respiration, inventories of labile organic matter, macrobenthic biomass) may act as “low-pass” filters, responding to longer-term (e.g., inter-annual) trends in water-column production. Bentho-pelagic coupling clearly will be altered by Antarctic climate change as patterns of sea-ice cover and water-column recycling vary. However, the nature of such climate-driven changes will be very difficult to predict without further studies of Antarctic benthic ecosystem response to (1) inter-annual variability in export flux, and (2) latitudinal gradients in duration of sea-ice cover and benthic ecosystem function. (c) 2006 Elsevier Ltd. All rights reserved.
Catastrophe, recovery and range limitation in NE Pacific kelp forests: a large-scale perspective
Edwards, MS Estes, JA
MARINE ECOLOGY-PROGRESS SERIES 320: 79-87
The 1997-98 El Nino was one of the strongest on record and resulted in widespread losses of the giant kelp Macrocystis pyrifera (Agardh) along the west coast of North America. Drawing on a rich history of studies that have shown abnormally large waves and warm nutrient-poor water associated with El Ninos to negatively impact giant kelp populations at some locations in southern and Baja California, we examined (1) how these impacts scale up when considered across the species’ geographic range in the NE Pacific Ocean and (2) if these impacts are generalizable over broad spatial scales. Working at 56 sites in 14 study locations over a 3 yr period (1997 to 2000), we examined how giant kelp populations were impacted by and recovered following the 1997-98 El Niho over a similar to 1500 km span along the west coast of North America. Our results indicate that while nearly all giant kelp disappeared from the southern one-third of the species’ range along the coast of Baja California, Mexico, and heavy losses occurred throughout the central one-third of the species’ range in southern California, USA, only minor impacts were observed throughout the northern one-third of the species’ range in central California. Further, although highly variable among regions, these impacts were similar and generalizable among locations within each region. Our results also suggest that, as has been observed in local-scale studies, this large-scale variability in giant kelp mortality was driven by large-scale patterns in ocean temperature (nutrient concentration) and wave intensity. Recovery following El Niho, in contrast, was variable at multiple spatial scales and although not directly tested here, presumably influenced by numerous factors such as proximity to upwelling areas, competition with other algae, grazing, and propagule availability. Further, variability in the rates of recovery among locations resulted in a generally slow recovery of giant kelp throughout most of Baja California, and residual large-scale impacts of the El Niho were still evident 2 yr after the El Niho ended. As global climate change may lead to increases in the frequency and intensity of El Ninos, our findings have broad implications for the ways in which ecosystems might be expected to respond to them and provide a measure by which their impacts to giant kelp ecosystems may be compared among events.
Climate change manipulations show Antarctic flora is more strongly affected by elevated nutrients than water
Wasley, J Robinson, SA Lovelock, CE Popp, M
GLOBAL CHANGE BIOLOGY 12:9 1800-1812
Climate change is expected to affect the high latitudes first and most severely, rendering Antarctica one of the most significant baseline environments for the study of global climate change. The indirect effects of climate warming, including changes to the availability of key environmental resources, such as water and nutrients, are likely to have a greater impact upon continental Antarctic terrestrial ecosystems than the effects of fluctuations in temperature alone. To investigate the likely impacts of a wetter climate on Antarctic terrestrial communities a multiseason, manipulative field experiment was conducted in the floristically important Windmill Islands region of East Antarctica. Four cryptogamic communities (pure bryophyte, moribund bryophyte, crustose and fructicose lichen-dominated) received increased water and/or nutrient additions over two consecutive summer seasons. The increased water approximated an 18% increase in snow melt days (0.2 degrees C increase in temperature), while the nutrient addition of 3.5g Nm(-2) yr(-1) was within the range of soil N in the vicinity. A range of physiological and biochemical measurements were conducted in order to quantify the community response. While an overall increase in productivity in response to water and nutrient additions was observed, productivity appeared to respond more strongly to nutrient additions than to water additions. Pure bryophyte communities, and lichen communities dominated by the genus Usnea, showed stronger positive responses to nutrient additions, identifying some communities that may be better able to adapt and prosper under the ameliorating conditions associated with a warmer, wetter future climate. Under such a climate, productivity is overall likely to increase but some cryptogamic communities are likely to thrive more than others. Regeneration of moribund bryophytes appears likely only if a future moisture regime creates consistently moist conditions.
Growth responses of two dominant C4 grass species to altered water availability
Swemmer, AM Knapp, AK Smith, MD
INTERNATIONAL JOURNAL OF PLANT SCIENCES 167:5 1001-1010
Identifying key ecophysiological traits that differ among dominant plant species and can be linked to species-specific responses to drought would improve our ability to forecast community and ecosystem responses to global climate change. The mesic grasslands of the central plains of North America are dominated by two C-4 grass species, Andropogon gerardii and Sorghastrum nutans, which purportedly differ in their tolerance of water stress. Individuals of these two species were grown in the field under rain-out shelters and subjected to wet (watered every 2-3 d) or dry (repeatedly subjected to wilting before watering) soil moisture regimes. A range of ecophysiological traits potentially important for tolerating water stress were concurrently measured. Although few traits differed between the species in the wet treatment, several traits were identified in the dry treatment that may enable A. gerardii to better tolerate drought. These were greater allocation to roots, reduced allocation to flowering, more rapid leaf turnover, and more rapid recovery of photosynthesis after wilting. The latter two traits may be particularly important for coping with increased variability in rainfall regimes in the future and are consistent with recently documented responses of A. gerardii to experimental increases in soil moisture variability.
Middle Pleistocene glacier behaviour in the Mediterranean: sedimentological evidence from the Pindus Mountains, Greece
Hughes, PD Gibbard, PL Woodward, JC
JOURNAL OF THE GEOLOGICAL SOCIETY 163: 857-867
Detailed sedimentological analyses of diamicton sequences in two areas of the Pindus Mountains, Greece, indicate multiple episodes of glacier advance and retreat during cold stages of the Middle-Pleistocene. These glacial sequences represent some of the most southerly in Europe and are important archives of regional and global climate change. The Pindus glaciers were relatively small by world standards and would have been highly responsive to changes in air temperature and precipitation. On Mount Tymphi, at least three phases of glacier advance are recorded within deposits assigned to the Skamnellian Stage (MIS 12). Further north on Mount Smolikas, a thick multiple diamicton sequence records evidence for multiple glacier advances during both the Skamnellian Stage and the Vlasian Stage (MIS 6). These records highlight the dynamic nature of glacier behaviour in the Mediterranean mountains during the Middle Pleistocene and provide new evidence for unstable cold stage climates.
Accumulation and release of methane from clathrates below the Laurentide and Cordilleran ice sheets
Weitemeyer, KA Buffett, BA
GLOBAL AND PLANETARY CHANGE 53:3 176-187
Ice-age cycles are associated with large fluctuations in the concentration of atmospheric methane. These fluctuations are commonly attributed to changes in wetlands, although clathrates have also been proposed as a potential source. We examine the possibility that methane clathrates accumulate below continental ice sheets during an ice age. The source of methane is due to microbial decomposition of organic material below the ice sheet. Methane is stored in clathrate when the pressure and temperature conditions permit thermodynamic stability. Deglaciation releases methane from clathrate into the atmosphere. We use a numerical model for the Laurentide-Cordilleran ice sheet [Marshall, S.J., Tarasov, L., Clarke, G.K.C., Peltier, W.R., 2000. Glaciological reconstruction of the Laurentide ice sheet: physical processes and modeling challenges, Can. J. Earth Sci. 37, 769-793.] to assess the aerial extent, thickness, and the thermal conditions at the base of the ice sheet as a function of time. Both low and high inventories of the organic carbon below the ice sheet are considered, based on soil carbon estimates for tundra and for the present potential vegetation. We model the spatial distribution of clathrate as the ice sheet grows and quantify the amplitude and timing of methane releases as the ice sheet retreats. The predicted fluctuations in atmospheric methane are 80-200 ppbv, which are comparable to fluctuations recorded in ice cores from Greenland and Antarctica. However, clathrates cannot explain the entire atmospheric methane record because there is insufficient methane in clathrate to sustain the elevated atmospheric concentration for more than 1 kyr. (C) 2006 Elsevier B.V. All rights reserved.
Toward synthesis of relationships among leaf longevity, instantaneous photosynthetic rate, lifetime leaf carbon gain, and the gross primary production of forests
Kikuzawa, K Lechowicz, MJ
AMERICAN NATURALIST 168:3 373-383
The assimilation of carbon by plant communities (gross primary production [GPP]) is a central concern in plant ecology as well as for our understanding of global climate change. As an alternative to traditional methods involving destructive harvests or time-consuming measurements, we present a simple, general model for GPP as the product of the lifetime carbon gain by a single leaf, the daily leaf production rate, and the length of the favorable period for photosynthesis. To test the model, we estimated leaf lifetime carbon gain for 26 species using the concept of mean labor time for leaves (the part of each day the leaf functions to full capacity), average potential photosynthetic capacity over the leaf lifetime, and functional leaf longevity (leaf longevity discounted for periods within a year wholly unfavorable for photosynthesis). We found that the lifetime carbon gain of leaves was rather constant across species. Moreover, when foliar biomass was regressed against functional leaf longevity, aseasonal and seasonal forests fell on a single line, suggesting that the leaf production rate during favorable periods is not substantially different among forests in the world. The gross production of forest ecosystems then can be predicted to a first approximation simply by the annual duration of the period favorable for photosynthetic activity in any given region.
An Arctic-breeding bird survey on the northwestern Ungava Peninsula, Quebec, Canada
ARCTIC 59:3 311-318
Knowledge of breeding bird distribution and abundance in the Canadian Arctic remains rudimentary for many species, particularly for shorebirds and songbirds. To help fill this gap, randomly selected plots were surveyed on the northwestern coast of the Ungava Peninsula, Quebec, Canada, during 2002. Thirty-eight species were recorded at 34 sites, where small songbirds were much more frequent than shorebirds. Breeding waterbirds were more abundant at low elevations near the coast, and songbirds tended to be more abundant at higher elevations. A high occurrence of nesting hawks and owls was probably the result of a high lemming population. Information from the survey extended the known breeding ranges of green-winged teal, spotted sandpiper, pectoral sandpiper, dunlin, American golden-plover, Wilson’s snipe, and short-eared owl. Further work on the Ungava Peninsula would likely document additional Arctic-breeding bird species. A more thorough knowledge of Arctic-breeding bird distribution will be needed to determine how species might be affected by global climate change.
The global-scale temperature and moisture dependencies of soil organic carbon decomposition: an analysis using a mechanistic decomposition model
Ise, T Moorcroft, PR
BIOGEOCHEMISTRY 80:3 217-231
Since the decomposition rate of soil organic carbon (SOC) varies as a function of environmental conditions, global climate change is expected to alter SOC decomposition dynamics, and the resulting changes in the amount of CO2 emitted from soils will feedback onto the rate at which climate change occurs. While this soil feedback is expected to be significant because the amount of SOC is substantially more than the amount of carbon in the atmosphere, the environmental dependencies of decomposition at global scales that determine the magnitude of the soil feedback have remained poorly characterized. In this study, we address this issue by fitting a mechanistic decomposition model to a global dataset of SOC, optimizing the model’s temperature and moisture dependencies to best match the observed global distribution of SOC. The results of the analysis indicate that the temperature sensitivity of decomposition at global scales (Q(10)=1.37) is significantly less than is assumed by many terrestrial ecosystem models that directly apply temperature sensitivity from small-scale studies, and that the maximal rate of decomposition occurs at higher moisture values than is assumed by many models. These findings imply that the magnitude of the soil decomposition feedback onto rate of global climate change will be less sensitive to increases in temperature, and modeling of temperature and moisture dependencies of SOC decomposition in global-scale models should consider effects of scale.
General equilibrium effects of a supply side GHG mitigation option under the Clean Development Mechanism
Timilsina, GR Shrestha, RM
JOURNAL OF ENVIRONMENTAL MANAGEMENT 80:4 327-341
The Clean Development Mechanism (CDM) under the Kyoto Protocol to the United Nations Framework Convention on Climate Change is considered a key instrument to encourage developing countries’ participation in the mitigation of global climate change. Reduction of greenhouse gas (GHG) emissions through the energy supply and demand side activities are the main options to be implemented under the CDM. This paper analyses the general equilibrium effects of a supply side GHG mitigation option-the substitution of thermal power with hydropower-in Thailand under the CDM. A static multi-sector general equilibrium model has been developed for the purpose of this study. The key finding of the study is that the substitution of electricity generation from thermal power plants with that from hydropower plants would increase economic welfare in Thailand. The supply side option would, however, adversely affect the gross domestic product (GDP) and the trade balance. The percentage changes in economic welfare, GDP and trade balance increase with the level of substitution and the price of certified emission reduction (CER) units. (c) 2006 Elsevier Ltd. All rights reserved.
Energy prices and turning points: The relationship between income and energy use/carbon emissions
Richmond, AK Kaufmann, RK
ENERGY JOURNAL 27:4 157-180
Models used to test whether an environmental Kuznets curve (EKC) can be used to describe the relationship between GDP and energy use and/or carbon emissions may be biased by the omission of energy prices. Here we include real energy prices and fuel shares in models that describe energy use and carbon emissions. We test if these models show a turning point in OECD countries. Results indicate that including energy prices eliminates statistical support for a turning point and suggest that the relationship between income and both energy use and carbon emissions is represented most accurately by diminishing returns. These results imply that economic growth per se will not reduce energy use or emissions that cause global climate change.
Level physiology, biomass, and reproduction of Phytolacca americana under conditions of elevated carbon dioxide and increased nocturnal temperature
Wolfe-Bellin, KS He, JS Bazzaz, FA
INTERNATIONAL JOURNAL OF PLANT SCIENCES 167:5 1011-1020
Rising atmospheric CO2 and increasing air temperatures are predicted to increase future plant growth, but plant responses to increasing temperatures could be complicated by the fact that nocturnal temperatures may increase more than diurnal temperatures. The C-3 forb Phytolacca americana L. (Phytolaccacea) was grown under either ambient (370 mu mol mol(-1)) or elevated (740 mmol mol(-1)) CO2 in either of two nocturnal temperature treatments (26 degrees/20 degrees C or 26 degrees/24 degrees C day/night). We predicted that elevated CO2 would increase photosynthetic rate and enhance plant biomass, while elevated nocturnal temperature would increase dark respiration rate and decrease biomass. Thus, increased nocturnal temperature was predicted to diminish the generally positive effects of elevated CO2 on plant growth. Plants grown under elevated CO2 responded as expected, with 69% greater photosynthetic rate and 35% larger whole-plant biomass for the first part of the growing season. Contrary to the predictions, however, increased nocturnal temperature had no negative effect on respiration rate or biomass. In fact, plants grown at higher nocturnal temperatures flowered 1.5 d earlier and exhibited a 32% increase in biomass allocation to reproduction. Thus, higher nocturnal temperatures did not diminish the generally positive effects of elevated CO2 on P. americana growth. Instead, these results indicate that elevated CO2 and increasing nocturnal temperatures of the future could have a neutral or even positive effect on P. americana population growth.
CDM potential for rural transition in China case study: Options in Yinzhou district, Zhejiang province
Zhao, XS Michaelowa, A
ENERGY POLICY 34:14 1867-1882
This paper aims to examine the potential of the clean development mechanism (CDM) to address energy-related issues during the rural transition process in China, using a case study of quickly urbanizing and industrializing Yinzhou district in coastal Zhejiang province. Yinzhou’s per capita GDP reached US$ 3 100 in 2002, three times China’s average, and is targeted to achieve $10,000 in 2020. We assess the current energy status of Yinzhou, and provide projections of energy consumption and CO2 emissions up to the year 2020. Energy resource shortages and limited possibilities to obtain coal-fired electricity from national grid illustrate the opening gap between energy supply and demand. We find that Yinzhou’s CDM potential is concentrated in efficiency improvement on the demand side. In that context, we suggest to systematically explore the CDM potential in the industrial sector. Projects will have to involve many stakeholders and the necessary local capacity has to be built. These CDM projects can be considered as killing three birds with one stone, namely maintaining continuous economic growth, alleviating local environmental pollution as well as mitigating global climate change. (c) 2005 Elsevier Ltd. All rights reserved.
Participation of Latin America and the Caribbean in the global climatological records, GHCN
Giddings, L Soto, M
INTERCIENCIA 31:9 632-637
It is impossible to overestimate the importance of historical meteorological records for studies of global climate change. Many of these studies are based on data in GHCN, the Global Historical Climatology Network, a meteorological data compilation available over the Internet that is comprised of voluntary contributions from all over the world. Even though the participation of countries is worthy of note, it should also be recognized that their contributions vary in quality and quantity, and especially in being tip to date. Data of many Latin American countries are incomplete and not up to date, which can cause errors in studies based on these data. Tables and figures show the participation of countries. In the name of researchers of climate change, the authors urge the authorities of all countries to change their policies so that their contributions’ to GHCN will be more complete and up to date.
The connection between the climate change model and a building’s thermal response model: A case of Slovenia
Vidrih, B Dolinar, M Medved, S
STROJNISKI VESTNIK-JOURNAL OF MECHANICAL ENGINEERING 52:9 568-586
The world’s leading climatologists believe that global climate changes are inevitable. The basis for this is the fact that we are already facing climate changes that will become even more significant in the future. The impact of climate changes is and will be noticeable in all fields of human activity; therefore, it will also influence the supply and demand of energy. Since we are observing a longer period of time, comparable to the lifespan of a building, and the amount of energy demanded is an important factor it is necessary to adjust the building and the renovation of buildings to the predicted climate changes. The prediction of a building’s thermal response is the basis for the integral planning of the building and building services installation with which we create suitable living conditions. In order to predict the expected changes in the building’s thermal response in the future it is necessary to correct the available meteorological variable databases today. In this paper we present various climate-change scenaria expected for Slovenia and the methods for correcting the starting points of the local meteorological databases. For the correction we used simplified mathematical models with which we-by forming test reference years (TRYs)-elaborate corrected test reference years (CTRYs). The latter are used for declaring the changes in energy demand in buildings and the effectiveness of a chosen building services installation that uses natural energy sources. As regards the predicted climate scenaria for the continental part of Slovenia, the energy use for heating buildings will be reduced by 1.5% to 31.4%. These climate changes will have a substantial influence on the thermal comfort in buildings during the summer In the heavyweight and naturally ventilated residential buildings that are currently thermally comfortable, suitable summer temperatures will be exceeded during 20% to 33% of the summer The effectiveness of natural and passive cooling techniques will radically change. In cooled buildings we can expect a 2-to-40-fold increase in the use of final (end-use) cooling energy when compared to today. The results presented in this paper confirm the fact that it is necessary to evaluate the consequences of global climate changes also from the point of view of energy use in buildings, their construction and building services installations. (c) 2006 Journal of Mechanical Engineering. All rights reserved.
Modelling dispersal of a temperate insect in a changing climate
Walters, RJ Hassall, M Telfer, MG Hewitt, GM Palutikof, JP
PROCEEDINGS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES 273:1597 2017-2023
We construct a novel individual-based random-walk model to assess how predicted global climate change might affect the dispersal rates of a temperate insect. Using a novel approach we obtained accurate field measurements of daily movements for individuals over time to parameterize our model. Males were found to move significantly further on average than females. Significant variation in movement was evident among individuals; the most dispersive individuals moved up to five (females) and seven (males) times as far on average as the least dispersive individuals. Mean relative daily movement of both males and females were exponentially related to maximum daily temperature recorded within the grass sward. Variability, both within and among individuals, in relative daily movement was incorporated into the model using gamma probability distributions. Resultant dispersal functions for seasonal movement are predicted to be highly leptokurtic, which agrees well with observations from the field. Predictions of the model suggest that for populations at the polewards edge of the current range an increase of 3-5 degrees C in daily maximum temperature may increase the proportion of long-distance dispersers (those characterized as comprising the top 0.1 % of furthest dispersing individuals under local conditions experienced during the 1963-1990 period) by up to 70%.
An optimised method for the extraction and analysis of lipid biomarkers from stalagmites
Blyth, AJ Farrimond, P Jones, M
ORGANIC GEOCHEMISTRY 37:8 882-890
Lipid compositions preserved in stalagmites have significant potential for use in reconstruction of global climate change and regional vegetation cover, but the low organic content of stalagmites poses a problem both for clean extraction and for obtaining a high temporal resolution in palaeoenvironmental records. Here, we present an acid digestion method optimised for cleanliness and maximum lipid recovery. The use of acid digestion and hydrolysis improves lipid yields not only by releasing organic matter trapped within individual calcite crystals, but also by allowing access to the chemically-bound pool of lipids, particularly acidic compounds such as alkanoic acids, hydroxy acids, and alkanedioic acids. The technique also considerably reduces contamination problems in comparison to conventional soxhlet extraction. (c) 2006 Elsevier Ltd. All rights reserved.
Monitoring coral bleaching using a colour reference card
Siebeck, UE Marshall, NJ Kluter, A Hoegh-Guldberg, O
CORAL REEFS 25:3 453-460
Assessment of the extent of coral bleaching has become an important part of studies that aim to understand the condition of coral reefs. In this study a reference card that uses differences in coral colour was developed as an inexpensive, rapid and non-invasive method for the assessment of bleaching. The card uses a 6 point brightness/saturation scale within four colour hues to record changes in bleaching state. Changes on the scale of 2 units or more reflect a change in symbiont density and chlorophyll a content, and therefore the bleaching state of the coral. When used by non-specialist observers in the field (here on an intertidal reef flat), there was an inter-observer error of I colour score. This technique improves on existing subjective assessment of bleaching state by visual observation and offers the potential for rapid, wide-area assessment of changing coral condition.
Long-term cosmic ray intensity variation and part of global climate change, controlled by solar activity through cosmic rays
PARTICLE ACCELERATION, SPACE PLASMA PHYSICS, SOLAR RADIATION AND THE EARTH’S ATMOSPHERE AND CLIMATE 37:8 1621-1628
In this paper, we investigate properties long-term variations in galactic cosmic ray intensity as an important possible link in the connection between solar activity variation and global climate change. There are two main aims of the paper: (1) to estimate how solar activity influences on galactic CR long-term variations, what are the relative role in this influence of convection-diffusion modulation and drift modulation and (2) to estimate the expected part of global climate change which may be caused by the influence of solar activity cycle on climate through 11- and 22-year cosmic ray variations. (c) 2006 Published by Elsevier Ltd on behalf of COSPAR.
Rapid fluctuation of alkenone temperature in the southwestern Okhotsk Sea during the past 120 ky
Harada, N Ahagon, N Sakamoto, T Uchida, M Ikehara, M Shibata, Y
GLOBAL AND PLANETARY CHANGE 53:1-2 29-46
Sea-ice expansion in the Okhotsk Sea in winter is sensitively affected by global warming and cooling. Regionally, the southwestern Okhotsk Sea is closely linked to climate change in East Asia, including Japan, because the cold sea surface temperature (SST) in the southwestern Okhotsk Sea influences directly the development of the Okhotsk atmospheric high-pressure system, and the activated Okhotsk high causes cold climatic conditions in northern Japan. Therefore, environmental change in the Okhotsk Sea indicates two-way interactions as a sensitive mirror reflecting global climate change and as a driving force of regional climate change. To better understand how surface environmental changes in the Okhotsk Sea can influence climate change in East Asia, SSTs were estimated in the southwestern Okhotsk Sea for the past 120 ky with millennial to centennial time resolution using the long-chain unsaturated alkyl ketone (alkenone) thermometer. The alkenone temperature, which corresponds to the SST to 20 in depth in autumn, showed repeated abrupt changes at a centennial timescale, especially during the last glacial period, 20-60 ky before present (BP). The alkenone temperature changed concurrently with changes from interstadials (warm events) to stadials (cold events) in the delta O-18 record of the ice cores from Greenland, although some interstadials could not be identified in the alkenone temperature record. A wavelet power spectrum analysis showed that a periodicity of about 8 ky was prominent during 10-90 ky BP, and a 4- to 5-ky cycle was characteristic during 30-40 ky BP in the alkenone temperature records. These periodicities were both similar and dissimilar to those in the Polar Circulation Index, which is based on the atmospheric circulation intensity at high latitudes, as recorded by major-ion concentrations in GISP2. Both the similarity and dissimilarity imply that the SST in the southwestern Okhotsk Sea is controlled mainly by the atmosphere-ocean circulation system in the Northern Hemisphere; however, the relationship between the SST in the Okhotsk Sea and the climate in the Greenland is not linear. Anomalously high alketione temperatures occurred repeatedly in the glacial period. These warm alkenone temperature episodes would have had multiple causes. In particular, high alkenone temperatures during the last glacial maximum (LGM) have been reported previously for locations near this study site. More investigations are necessary to understand what happened in the Okhotsk Sea and in adjacent seas at the time of the LGM. (C) 2006 Elsevier B.V. All rights reserved.
Effects of environmental hypercapnia on animal physiology: A C-13 NMR study of protein synthesis rates in the marine invertebrate Sipunculus nudus
Langenbuch, M Bock, C Leibfritz, D Portner, HO
COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY A-MOLECULAR & INTEGRATIVE PHYSIOLOGY 144:4 479-484
Global climate change is associated with a progressive rise in ocean CO2 concentrations (hypercapnia) and, consequently, a drop in seawater pH. However, a comprehensive picture of the physiological; mechanisms affected by chronic CO2 stress in marine biota is still lacking. Here we present an analysis of protein biosynthesis rates in isolated muscle of the marine invertebrate Sipunculus nudus, a sediment dwelling worm living at various water depths. We followed the incorporation of 13 C-labelled phenylalanine into muscular protein via high-resolution NMR spectroscopy. Protein synthesis decreased by about 60% at a medium pH of 6.70 and a consequently lowered intracellular pH (pHi). The decrease in protein synthesis rates is much stronger than the concomitant suppression of protein degradation (60% versus 10-15%) possibly posing a threat to the cellular homeostasis of structural as well as functional proteins. Considering the progressive rise in ocean CO2 concentrations, permanent disturbances of cellular protein turnover might seriously affect growth and reproductive performance in many marine organisms with as yet unexplored impacts on species density and composition in marine ecosystems. (c) 2006 Elsevier Inc. All rights reserved.
Evidence for trends in the Northern Hemisphere water cycle
Dirmeyer, PA Brubaker, KL
GEOPHYSICAL RESEARCH LETTERS 33:14 -
We have applied a unique water vapor tracing algorithm using observed precipitation and atmospheric analyses for the period 1979-2003 to estimate water budgets and recycling ratio (the fraction of precipitation over a region that originated as evaporation from the same region) over land areas across the globe. Over most mid- and high-latitude areas, a strong annual cycle of recycling ratio exists; low during winter when storm tracks are active, tropospheric circulation strong, and surface evaporation rates low, high during summer when winds are light and evaporation is greater. Trends in recycling ratio have been found over large areas at high-latitudes that are consistent with an expansion into spring of the warm-season regime of water vapor recycling. These trends are consistent with observed vegetation-related changes often attributed to global climate change, and are most evident over northern Europe and North America where the density of meteorological data influencing the atmospheric analyses is high. Less extensive trends are found in other seasons.
Temperature-dependent phenology and predation in arthropod systems
Logan, JD Wolesensky, W Joern, A
ECOLOGICAL MODELLING 196:3-4 471-482
A central issue in ecology is to determine how environmental variations associated with global climate change, especially changing temperatures, affect trophic interactions in various ecosystems. This paper develops a temperature-dependent, stage-based, discrete, cohort model of the population dynamics of an insect pest under pressure from a predator. Guided by experimental data, the model is applied specifically to predation of grasshoppers by rangeland lycosid spiders. The development rate of insect arthropods is strongly affected by temperature, and these temperature-dependent phenological effects couple with shifts in the daily activity periods for both prey and predator, thereby increasing or decreasing opportunities for interaction. The model addresses these effects quantitatively by introducing a temperature-dependent, joint-activity factor that enters the predator’s functional response. The model also includes a prey mortality rate that is temperature-dependent through the prey development rate. The model is parameterized using field and experimental data for spiders and grasshoppers. We investigate the effect of the solar power index (sunlight), mean temperature, and temperature variation, as measured by amplitude, on the developmental times and survivorship, both with, and without, predation. We conclude that increasing variation in temperature results in a stronger relative effect on survivorship due to predation. (c) 2006 Elsevier B.V. All rights reserved.
Geological and geomorphological insights into Antarctic ice sheet evolution
Sugden, DE Bentley, MJ Cofaigh, CO
PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES 364:1844 1607-1625
Technical advances in the study of ice-free parts of Antarctica can provide quantitative records that are useful for constraining and refining models of ice sheet evolution and behaviour. Such records improve our understanding of system trajectory, influence the questions we ask about system stability and help to define the ice-sheet processes that are relevant on different time-scales. Here, we illustrate the contribution of cosmogenic isotope analysis of exposed bedrock surfaces and marine geophysical surveying to the understanding of Antarctic ice sheet evolution on a range of time-scales. In the Dry Valleys of East Antarctica, 3 He dating of subglacial flood deposits that are now exposed on mountain summits provide evidence of an expanded and thicker Mid-Miocene ice sheet. The survival of surface boulders for approximately 14 Myr, the oldest yet measured, demonstrates exceptionally low rates of subsequent erosion and points to the persistence and stability of the dry polar desert climate since that time. Increasingly, there are constraints on West Antarctic ice sheet fluctuations during Quaternary glacial cycles. In the Sarnoff Mountains of Marie Byrd Land in West Antarctica, Be-10 and Al-26 cosmogenic isotope analysis of glacial erratics and bedrock reveal steady thinning of the ice sheet from 10 400 years ago to the present, probably as a result of grounding line retreat. In the Antarctic Peninsula, offshore analysis reveals an extensive ice sheet at the last glacial maximum. Based on radiocarbon dating, deglaciation began by 17 000 cal. yr BP and was complete by 9500 cal yr BP. Deglaciation of the west and east sides of the Antarctic Peninsula ice sheet occurred at different times and rates, but was largely complete by the Early Holocene. At that time ice shelves were less extensive on the west side of the Antarctic Peninsula than they are today. The message from the past is that individual glacier drainage basins in Antarctica respond in different and distinctive ways to global climate change, depending on the link between regional topography and climate setting.
A stage-based study of drought response in Cryptantha flava (Boraginaceae): Gas exchange, water use efficiency, and whole plant performance
Casper, BB Forseth, IN Wait, DA
AMERICAN JOURNAL OF BOTANY 93:7 978-987
Models of global climate change predict an increase in the frequency of major droughts, yet we know little about the consequences of drought for the demography of natural populations. This study examined a population of the semi-desert perennial Cryptantha flava (Boraginaceae) to determine how plants of different developmental stages respond to drought through changes in leaf gas exchange, leaf water potential, water use efficiency, growth, and reproduction. In two of the four years, drought was applied using rainout shelters, and a severe natural drought occurred in another. Small, presumably younger, plants sometimes had lower rates of maximum photosynthesis, lower leaf water potentials, and lower instantaneous or integrated water-use efficiency than large plants. Small plants also had higher relative growth rates and lower reproductive effort. Large plants with evidence of shrinkage from a previously larger size often produced less growth and reproduction than large healthy plants, suggesting a decline in plant vigor with age. Drought depressed gas exchange and leaf water potentials equally in all plant stages. Thus, leaf-level physiological attributes provide no clues for why drought reduces growth more strongly in large plants. The results point to several additional avenues of research relevant to understanding stage-dependent or age-dependent plant performance under drought conditions.
The persuasive power of mediated risk experiences
Meijnders, A Midden, C McCalley, T
PERSUASIVE TECHNOLOGY 3962: 50-54
This paper discusses the use of multimedia techniques and augmented reality tools to bring across the risks of global climate change. We look back on a series of experiments showing that vividness is a key factor in creating emotional risk responses and fostering attitude change through systematic information processing. However, the effects were modest even when vivid and concrete images and texts were used in combination with ominous sounds and music. The next step therefore is to explore and make use of the possibilities of multimedia techniques and augmented reality to provide people with a simulated risk experience. This paper concludes with a preview of this work, the focus of which is on the sense of presence.
Are dust storm activities in North China related to Arctic ice-snow cover?
Zhang, JS Peng, GB Huang, M Zhang, SH
GLOBAL AND PLANETARY CHANGE 52:1-4 225-230
The generation and development of dust storms are controlled by land surface conditions and atmospheric circulations. The latter, in turn, is influenced by the global ice-snow cover. In this study, we examine the relationship between the characteristics of dust storm activities in north China and the changes of global climate patterns. In particular, we are interested in whether Arctic ice-snow cover is related to the dust storm frequencies and intensities in north China. Our analysis, based on the monthly data for the period from 1954 to 1994, shows that this is indeed the case. This result suggests that the Arctic ice-snow cover can be used for the long-term prediction of dust storm activities in north China, and dust storm activities also serve as an indicator of global climate change. (C) 2006 Published by Elsevier B.V.
The generational divide in support for environmental policies: European evidence
Hersch, J Viscusi, WK
CLIMATIC CHANGE 77:1-2 121-136
This article examines age variations in support for environmental protection policies that affect climate change using a sample of over 14,000 respondents to a 1999 Eurobarometer survey. There is a steady decline with age in whether respondents are willing to incur higher gasoline prices to protect the environment. This relationship remains after controlling for socioeconomic characteristics. There are age-related differences in information about environmental risks, information sources about the environment, perceived health risks from climate change, and degree of worry about climate change. However, taking these factors into account does not eliminate the age variation in willingness to pay more for gasoline to protect the environment.
Effects of elevated atmospheric carbon dioxide on biomass and carbon accumulation in a model regenerating longleaf pine community
Runion, GB Davis, MA Pritchard, SG Prior, SA Mitchell, RJ Torbert, HA Rogers, HH Dute, RR
JOURNAL OF ENVIRONMENTAL QUALITY 35:4 1478-1486
Plant species vary in response to atmospheric CO2 concentration due to differences in physiology, morphology, phenology, and symbiotic relationships. These differences make it very difficult to predict how plant communities will respond to elevated CO2. Such information is critical to furthering our understanding of community and ecosystem responses to global climate change. To determine how a simple plant community might respond to elevated CO2, a model regenerating longleaf pine community composed of five species was exposed to two CO2 regimes (ambient, 365 mu mol mol(-1) and elevated, 720 mu mol mol(-1)) for 3 yr. Total above- and belowground biomass was 70 and 49% greater, respectively, in CO2-enriched plots. Carbon (C) content followed a response pattern similar to biomass, resulting in a significant increase of 13.8 Mg C ha(-1) under elevated CO2. Responses of individual species, however, varied. Longleaf pine (Pinus palustris Mill.) was primarily responsible for the positive response to CO2 enrichment. Wiregrass (Aristida stricta Michx.), rattlebox (Crotalaria rotundifolia Walt. Ex Gruel.), and butterfly weed (Asclepias tuberosa L.) exhibited negative above- and belowground biomass responses to elevated CO2, while sand post oak (Quercus margaretta Ashe) did not differ significantly between CO2 treatments. As with pine, C content followed patterns similar to biomass. Elevated CO2 resulted in alterations in community structure. Longleaf pine comprised 88% of total biomass in CO2-enriched plots, but only 76% in ambient plots. In contrast, wire-grass, rattlebox, and butterfly weed comprised 19% in ambient CO2 plots, but only 8% under high CO2. Therefore, while longleaf pine may perform well in a high CO2 world, other members of this community may not compete as well, which could alter community function. Effects of elevated CO2 on plant communities are complex, dynamic, and difficult to predict, clearly demonstrating the need for more research in this important area of global change science.
Some phenomena of the interaction between vegetation and a atmosphere on multiple scales
Hu, YQ Chen, JB Zheng, YR Li, GQ Zuo, HC
ADVANCES IN ATMOSPHERIC SCIENCES 23:4 639-648
This article studies the response of the distribution pattern and the physiological characteristics of the ecosystem to the spontaneous precipitation and the interaction between vegetation and the atmosphere on multiple scales in arid and semi-arid zones, based on measured data of the ecological physiological 14 parameters in the Ordas Plateau of northern China. The results show that the vegetation biomass and the energy use efficiency of photosynthesis are especially sensitive to the annual precipitation, strong and complex interactions exist between the vegetation and the atmosphere on multiple scales leading to supernormal thermal heterogeneity of the underlying surface, the strong vortex movement and turbulence. This study can facilitate understanding of the land surface processes and the influences of global climate change as well as human activities on the human environment in the arid and semi-arid zones. It also aids in improving the parameterization schemes of turbulent fluxes of a heterogeneous underlying surface for land surface processes in climate models.
A matter of timing: changes in the first date of arrival and last date of departure of Australian migratory birds
Beaumont, LJ McAllan, IAW Hughes, L
GLOBAL CHANGE BIOLOGY 12:7 1339-1354
Although there is substantial evidence that Northern Hemisphere species have responded to climatic change over the last few decades, there is little documented evidence that Southern Hemisphere species have responded in the same way. Here, we report that Australian migratory birds have undergone changes in the first arrival date (FAD) and last date of departure (LDD) of a similar magnitude as species from the Northern Hemisphere. We compiled data on arrival and departure of migratory birds in south-east Australia since 1960 from the published literature, Bird Observer Reports, and personal observations from bird watchers. Data on the FAD for 24 species and the LDD for 12 species were analyzed. Sixteen species were short- to middle-distance species arriving at their breeding grounds, seven were long-distance migrants arriving at their nonbreeding grounds, and one was a middle-distance migrant also arriving at its nonbreeding ground. For 12 species, we gathered data from more than one location, enabling us to assess the consistency of intraspecific trends at different locations. Regressions of climate variables against year show that across south-east Australia average annual maximum and minimum temperatures have increased by 0.17 degrees C and 0.13 degrees C decade(-1) since 1960, respectively. Over this period there has been an average advance in arrival of 3.5 days decade(-1); 16 of the 45 time-series (representing 12 of the 24 species studied) showed a significant trend toward earlier arrival, while only one time-series showed a significant delay. Conversely, there has been an average delay in departure of 5.1 days decade(-1); four of the 21 departure time-series (four species) showed a significant trend toward later departure, while one species showed a significant trend toward earlier departure. However, differences emerge between the arrival and departure of short- to middle-distance species visiting south-east Australia to breed compared with long-distance species that spend their nonbreeding period here. On average, short- to middle-distance migrants have arrived at their breeding grounds 3.1 days decade(-1) earlier and delayed departure by 8.1 days decade(-1), thus extending the time spent in their breeding grounds by similar to 11 days decade(-1). The average advance in arrival at the nonbreeding grounds of long-distance migrants is 6.8 days decade(-1). These species, however, have also advanced departure by an average of 6.9 days decade(-1). Hence, the length of stay has not changed but rather, the timing of events has advanced. The patterns of change in FAD and LDD of Australian migratory birds are of a similar magnitude to changes undergone by Northern Hemisphere species, and add further evidence that the modest warming experienced over the past few decades has already had significant biological impacts on a global scale.
Long-term population declines in Afro-Palearctic migrant birds
Sanderson, FJ Donald, PF Pain, DJ Burfield, IJ van Bommel, FPJ
BIOLOGICAL CONSERVATION 131:1 93-105
We present the first continent-wide analysis of the population trends of European breeding birds to show that populations of Afro-Palearctic migrant birds have shown a pattern of sustained, often severe, decline. The mean trend of inter-continental migrants was significantly negative between 1970 and 1990 and non-significantly so between 1990 and 2000. Mean population trends were positively correlated between periods, suggesting little change in the trajectory of most migrant species’ populations over this 30-year period. In both periods, trends of inter-continental migrants were significantly more negative than those of short-distance migrants or residents. This negative trend appeared to be largely, although not entirely, due to declines in species wintering in dry, open habitats in Africa. Analyses of trends of 30 closely related pairs of species, one a long-distance migrant and the other not, indicated significantly more negative trends in the former, irrespective of breeding habitat. Conservation action to address these declines is required under the Convention on Migratory Species and the Pan-European Biological and Landscape Diversity Strategy, to which most European countries are signatories and which aim, respectively, to conserve migratory species and to halt the loss of biodiversity by 2010. Our results indicate that more conservation action may be required outside Europe to achieve these targets. Further research is needed to assess whether the declines are caused by factors operating on the birds’ wintering grounds, breeding grounds or on migration routes, and to identify ways to reverse them. (c) 2006 Elsevier Ltd. All rights reserved.
Ecotypic variation in the context of global climate change: revisiting the rules
Millien, V Lyons, SK Olson, L Smith, FA Wilson, AB Yom-Tov, Y
ECOLOGY LETTERS 9:7 853-869
Patterns of ecotypic variation constitute some of the few ‘rules’ known to modern biology. Here, we examine several well-known ecogeographical rules, especially those pertaining to body size in contemporary, historical and fossil taxa. We review the evidence showing that rules of geographical variation in response to variation in the local environment can also apply to morphological changes through time in response to climate change. These rules hold at various time scales, ranging from contemporary to geological time scales. Patterns of body size variation in response to climate change at the individual species level may also be detected at the community level. The patterns underlying ecotypic variation are complex and highly context-dependent, reducing the ‘predictive-power’ of ecogeographical rules. This is especially true when considering the increasing impact of human activities on the environment. Nonetheless, ecogeographical rules may help interpret the likely influences of anthropogenic climate change on ecosystems. Global climate change has already influenced the body size of several contemporary species, and will likely have an even greater impact on animal communities in the future. For this reason, we highlight and emphasise the importance of museum specimens and the continued need for documenting the earth’s biological diversity.
Ecosystem recovery: heathland response to a reduction in nitrogen deposition
Power, SA Green, ER Barker, CG Bell, JNB Ashmore, MR
GLOBAL CHANGE BIOLOGY 12:7 1241-1252
Atmospheric deposition of nitrogen is responsible for widespread changes in the structure and function of sensitive seminatural ecosystems. The proposed reduction in emissions of nitrogenous pollutants in Europe under the Gothenburg Protocol raises the question of whether affected ecosystems have the potential to recover to their previous condition and, if so, over what timescale. Since 1998, we have monitored the response of a lowland heathland in southern England following the cessation of a long-term nitrogen addition experiment, and subsequent management, assessing changes in vegetation growth and chemistry, soil chemistry and the soil microbial community. Persistent effects of earlier nutrient loading on Calluna growth and phenology, and on the abundance of lichens, were apparent up to 8 years after nitrogen additions ceased, indicating the potential for long-term effects of modest nutrient loading (up to 15.4 kg N ha(-1) yr(-1), over 7 years) on heathland ecosystems. The size and activity of the soil microbial community was elevated in former N-treated plots, 6-8 years after additions ceased, suggesting a prolonged effect on the rate of nutrient cycling. Although habitat management in 1998 reduced nitrogen stores in plant biomass, effects on belowground nitrogen stores were small. Although some parameters (e.g. soil pH) recover pretreatment levels relatively rapidly, others (e.g. vegetation cover and microbial activity) respond much more slowly, indicating that the ecological effects of even small increases in nitrogen deposition will persist for many years after deposition inputs are reduced. Indeed, calculations suggest that the additional soil nitrogen storage associated with 7 years of experimental nitrogen inputs could sustain the observed effects on plant growth and phenology for several decades. Carry over effects on plant phenology and sensitivity to drought suggest that the persistence of vegetation responses to nitrogen deposition should be integrated into long-term assessments of the impact of global climate change on sensitive ecosystems.
Mediated modeling of the impacts of enhanced UV-B radiation on ecosystem services
van den Belt, M Bianciotto, OA Costanza, R Demers, S Diaz, S Ferreyra, GA Koch, EW Momo, FR Vernet, M
PHOTOCHEMISTRY AND PHOTOBIOLOGY 82:4 865-877
This article describes the use of group model building to facilitate interaction with stakeholders, synthesize research results and assist in the development of hypotheses about climate change at the global level in relation to UV-B radiation and ecosystem service valuation. The objective was to provide a platform for integration of the various research components within a multidisciplinary research project as a basis for interaction with stakeholders with backgrounds in areas other than science. An integrated summary of the scientific findings, along with stakeholder input, was intended to produce a bridge between science and policymaking. We used a mediated modeling approach that was implemented as a pilot project in Ushuaia, Argentina. The investigation was divided into two participatory workshops: data gathering and model evaluation. Scientists and the local stakeholders supported the valuation of ecosystem services as a useful common denominator for integrating the various scientific results. The concept of economic impacts in aquatic and marsh systems was represented by values for ecosystem services altered by UV-B radiation. In addition, direct local socioeconomic impacts of enhanced UV-B radiation were modeled, using data from Ushuaia. We worked with 5 global latitudinal regions, focusing on net primary production and biomass for the marine system and on 3 plant species for the marsh system. Ecosystem service values were calculated for both sectors. The synthesis model reflects the conclusions from the literature and from experimental research at the global level. UV-B is not a significant stress for the marshes, relative to the potential impact of increases in the sea level. Enhanced UV-B favors microbial dynamics in marine systems that could cause a significant shift from primary producers to bacteria at the community level. In addition, synergetic effects of UV-B and certain pollutants potentiate the shift to heterotrophs. This may impact the oceanic carbon cycle by increasing the ratio of respiratory to photosynthetic organisms in surface waters and, thus, the role of the ocean as a carbon sink for atmospheric CO2. In summary, although changes in the marine sector due to anthropogenic influences may affect global climate change, marshes are expected to primarily be affected by climate change.
Beyond Kyoto: A tax-based system for the global reduction of greenhouse gas emissions
Kahn, JR Franceschi, D
ECOLOGICAL ECONOMICS 58:4 778-787
The Kyoto Protocol represents an initial step in terms of solving the problem of global climate change. However, as with most first steps, the Kyoto Protocol must be followed by a full journey in order to reach the desired goal of preventing catastrophic global warming. The Kyoto Protocol does not lead to the necessary decline in the atmospheric concentrations of greenhouse gases, particularly because emissions of developing countries are not specifically addressed in the Protocol. We suggest a new agreement based on carbon taxes as a possibility to build upon the Kyoto Protocol and eventually freeze atmospheric concentrations at a level that prevents catastrophic climate change. (c) 2005 Elsevier B.V. All rights reserved.
Regional climate change and its effects on river runoff in the Tarim Basin, China
Chen, YN Takeuchi, K Xu, CC Chen, YP Xu, ZX
HYDROLOGICAL PROCESSES 20:10 2207-2216
The hydrological response to climate change in the Tarim River Basin was investigated by analysing the hydrological. temperature and precipitation data of the past 50 years. The long-term trend of the hydrological time-series, including air temperature, precipitation, and streamflow, was examined by using both parametric and non-parametric techniques and the plausible association between streamflow and climate change by the method of are), correlation analysis. The results show that the study area became warmer in the last few decades. The air temperature experienced a significant monotonic increase by 5%; the precipitation showed a significant decrease in the 1970s and then a major increase in the 1980s and 1990s, with average annual precipitation up by 6.8 nun per decade. A step change occurred in both temperature and precipitation around 1986, with mean temperature and precipitation increasing from 6.7 degrees C and 146 mm before 1986 to 7.3 degrees C and 180 mm respectively after 1986. The temperature has risen by nearly 1 degrees C over the past 50 years, possibly resulting from the impact of global climate change. Streamflows in the Aksu River and the Yarkant River have shown a significant (P < 0.05) tendency of increase. This is particularly the case for the Aksu River. The coefficients of streamflow increase in the Aksu and Yarkant Rivers are 0.41 and 0.13 respectively. The results of grey correlation analysis show that in the Aksu River. which is located in the northwest of the basin, the impact of precipitation on streamflow is much greater than that of temperature. However, in the Hotan River, which is located in the southwest of the basin, the impact of temperature on streamflow is much greater than that of precipitation. This is likely to be related to the geographic distribution of the headstreams of the rivers. Copyright (C) 2006 John Wiley & Sons, Ltd.
Rapid advance of spring arrival dates in long-distance migratory birds
Jonzen, N Linden, A Ergon, T Knudsen, E Vik, JO Rubolini, D Piacentini, D Brinch, C Spina, F Karlsson, L Stervander, M Andersson, A Waldenstrom, J Lehikoinen, A Edvardsen, E Solvang, R Stenseth, NC
SCIENCE 312:5782 1959-1961
Several bird species have advanced the timing of their spring migration in response to recent climate change. European short-distance migrants, wintering in temperate areas, have been assumed to be more affected by change in the European climate than long-distance migrants wintering in the tropics. However, we show that tong-distance migrants have advanced their spring arrival in Scandinavia more than short-distance migrants. By analyzing a long-term data set from southern Italy, we show that long-distance migrants also pass through the Mediterranean region earlier. We argue that this may reflect a climate-driven evolutionary change in the timing of spring migration.
Variation in the sensitivity of organismal body temperature to climate change over local and geographic scales
Gilman, SE Wethey, DS Helmuth, B
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA 103:25 9560-9565
Global climate change is expected to have broad ecological consequences for species and communities. Attempts to forecast these consequences usually assume that changes in air or water temperature will translate into equivalent changes in a species’ organismal body temperature. This simple change is unlikely because an organism’s body temperature is determined by a complex series of interactions between the organism and its environment. Using a biophysical model, validated with 5 years of field observations, we examined the relationship between environmental temperature change and body temperature of the intertidal mussel Mytilus califomianus over 1,600 km of its geographic distribution. We found that at all locations examined simulated changes in air or water temperature always produced less than equivalent changes in the daily maximum mussel body temperature. Moreover, the magnitude of body temperature change was highly variable, both within and among locations. A simulated 1 degrees C increase in air or water temperature raised the maximum monthly average of daily body temperature maxima by 0.07-0.92 degrees C, depending on the geographic location, vertical position, and temperature variable. We combined these sensitivities with predicted climate change for 2100 and calculated increases in monthly average maximum body temperature of 0.97-4.12 degrees C, depending on location and climate change scenario. Thus geographic variation in body temperature sensitivity can modulate species’ experiences of climate change and must be considered when predicting the biological consequences of climate change.
Regional climate change and its impact on photooxidant concentrations in southern Germany: Simulations with a coupled regional climate-chemistry model
Forkel, R Knoche, R
JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES 111:D12 -
[ 1] In order to investigate possible effects of global climate change on the near-surface concentrations of photochemical compounds in southern Germany, nested regional simulations with a coupled climate-chemistry model were carried out. The simulations with a horizontal resolution of 60 km for Europe and 20 km for central Europe were driven by meteorological boundary conditions provided by a long-term simulation of the global climate model ECHAM4. Two time slices of about 10 years were compared, one representing the 1990s and one representing the 2030s. For the region of southern Germany the simulations show an increase of the mean summer temperature by almost 2 degrees along with a decrease of cloud water and ice and a corresponding increase of the photolysis frequencies and the emissions of biogenic hydrocarbons. Under the model assumption of unchanged anthropogenic emissions this leads to an increase of the mean mixing ratios of most photooxidants. Because of the complex topography and the heterogeneous distribution of precursor emissions all parameters show pronounced regional patterns. The average daily maximum ozone concentrations in southern Germany increase for the considered scenario by nearly 10% in the summer months. Depending on the region, the increase of the mean daily maximum ranges between 2 and 6 ppb. As a consequence, the number of days when the 8-hour mean of the ozone concentration exceeds the threshold value of 120 mu g m(-3) increases by 5 to 12 days per year.
Scaling the metabolic balance of the oceans
Lopez-Urrutia, A San Martin, E Harris, RP Irigoien, X
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA 103:23 8739-8744
Oceanic communities are sources or sinks of CO2, depending on the balance between primary production and community respiration. The prediction of how global climate change will modify this metabolic balance of the oceans is limited by the lack of a comprehensive underlying theory. Here, we show that the balance between production and respiration is profoundly affected by environmental temperature. We extend the general metabolic theory of ecology to the production and respiration of oceanic communities and show that ecosystem rates can be reliably scaled from theoretical knowledge of organism physiology and measurement of population abundance. Our theory predicts that the differential temperature-dependence of respiration and photosynthesis at the organism level determines the response of the metabolic balance of the epipelagic ocean to changes in ambient temperature, a prediction that we support with empirical data over the global ocean. Furthermore, our model predicts that there will be a negative feedback of ocean communities to climate warming because they will capture less CO2 with a future increase in ocean temperature. This feedback of marine biota will further aggravate the anthropogenic effects on global warming.
Winds of change?: Projections of near-surface winds under climate change scenarios
Pryor, SC Schoof, JT Barthelmie, RJ
GEOPHYSICAL RESEARCH LETTERS 33:11 -
Changes in near - surface wind speeds due to global climate change may have profound geophysical and societal impacts. However, Global Climate Models (GCMs) are unable to replicate the historically observed magnitude and spatial variability of wind speeds, so we apply a downscaling technique to generate probability distributions of wind speeds at sites in northern Europe for historical periods ( 1961 - 1990 and 1982 - 2000) and two future periods ( 2046 - 2065, 2081 - 2100). Projections for the twenty-first century (C21st) indicate no evidence of substantial evolution relative to the end of the twentieth century (C20th), although there is increased divergence of results from downscaling of different GCMs toward the end of C21st. Predicted changes in the downscaled mean and 90th percentile wind speeds are small (< +/- 15%) and are comparable to the current variability manifest in downscaling from different GCMs.
Options and instruments for a deep cut in CO2 emissions: Carbon dioxide capture or renewables, taxes or subsidies?
Gerlagh, R Van der Zwaan, B
ENERGY JOURNAL 27:3 25-48
This paper compares both the main physical options and the principal policy instruments to realize a deep cut in carbon dioxide emissions necessary to control global climate change. A top-down energy-economy model is used that has three emission reduction options: energy savings, a transition towards less-carbon-intensive or non-carbon energy resources, and the use of carbon dioxide capture and storage technology. Five policy instruments - carbon taxes, fossil fuel taxes, non-carbon (renewable) energy subsidies, a portfolio standard for the carbon intensity of energy production, and a portfolio standard for the use of non-carbon (renewable) energy resources - are compared in terms of costs, efficiency and their impact on the composition of the energy supply system. One of our main conclusions is that a carbon intensity portfolio standard, involving the recycling of carbon taxes to support renewables deployment, is the most cost-efficient way to address the problem of global climate change. A comprehensive introduction of the capture and storage of carbon dioxide would contribute to reducing the costs of climate change control, but would not obviate the large-scale need for renewables.
Durability design of infrastructure and some related issues
CANADIAN JOURNAL OF CIVIL ENGINEERING 33:6 650-672
The life cycle performance of any infrastructure should be taken into consideration in its design, its construction, its maintenance, its operation, and when needed, its rehabilitation. The protection of infrastructure must be holistic, taking into account long-term socioeconomic and environmental considerations and the impact of the global climate change. Fulfilling the requirements of the ultimate and serviceability limit states over the service life of the facility requires an understanding of the use of the system, the deterioration response of the materials and their components when subjected to aggressive environments, and how this deterioration can be prevented or significantly delayed by preventive, remedial, and routine maintenance. The composition, microstructure, macrostructure, and various modes of deterioration of materials used in construction (steel, wood, concrete) are reviewed, along with possible remedial measures. The development of concrete as a construction material, its durability, and the relevant durability provisions in the various Canadian Standards Association standards are reviewed briefly. Current European practice and the 1990 Comite Euro-International du beton Design Guide for Durable Concrete Structures are evaluated. The engineer’s responsibility for durable performance of a facility and the importance of durability audits are also examined.
Life at the edge: an experimental study of a poleward range boundary
OECOLOGIA 148:2 270-279
Experimental studies of biogeographic processes are important, but rarely attempted because of the logistical challenges of research at large spatial scales. I used a series of large-scale transplant experiments to investigate the mechanisms controlling species abundance near a poleward range boundary. The intertidal limpet Collisella scabra experiences a 100-fold decline in abundance over the northernmost 300 km of its range. Temperature and food supply both strongly influenced individual survival, growth, and maturation. Regression analysis also revealed significant interactions among these conditions: the effect of one could not be predicted without knowing the level of the other. But these relationships could not explain geographic abundance patterns. Instead, individual limpets were highly successful at sites with relatively low abundance. These results suggest that, even though temperature is important to the success of individual C. scabra populations, the primary effect of warming temperatures under climate change may not be a shift in geographic distribution.
Changes in occurrence and abundance of northern/southern flatfishes over a 20-year period in a coastal nursery area (Bay of Vilaine) and on the eastern continental shelf of the Bay of Biscay
Desaunay, Y Guerault, D Le Pape, O Poulard, JC
SCIENTIA MARINA 70: Suppl. 1 193-200
Several works have demonstrated trends in the distribution of fish species relative to global warming. This study investigated whether similar trends have occurred for selected flatfish species on the continental shelf of the Bay of Biscay. These species were used as indicators and changes in their Populations were studied in a coastal nursery ground,where flatfish juveniles are concentrated as well as on the entire shelf. Previous studies analysing changes in sea surface temperature for the continental shelf indicate that winter warming occurred in the 1980s and 1990s. Sixteen autumn cruises conducted since 1981 in the Bay of Vilaine nursery area and I I autumn cruises since 1987 over the entire shelf provided data on a nearly annual basis for the abundance of benthic fish. The four most common flatfish species were selected and their occurrence and yearly abundance were analysed with regard to specific biogeographic ranges and climate change. Similar results were obtained for juveniles on a nursery scale and for all age groups on the entire shelf. Although sole (Solea solea) showed irregular yearly variations, northern winter spawners such as plaice (Pleuronectes platessa) and dab (Limanda limanda) exhibited significantly high abundance during the 1980s, followed by a continuing low level and ultimately zero catches. On the other hand, the wedge sole (Dicologoglossa cuneata), a southern summer spawner, showed an increasing trend in the late 1990s.
Spatial variation in anthropic and natural factors regulating the breeding success of the cinereous vulture (Aegypius monachus) in the SW Iberian Peninsula
Moran-lopez, R Sanchez, JM Costillo, E Corbacho, C Villegas, A
BIOLOGICAL CONSERVATION 130:2 169-182
The management of the cinereous vulture (Aegypius monachus) populations, the largest bird of the Western Palaearctic and considered an umbrella species, requires the understanding of the factors limiting the breeding success. As part of a management program, we studied such factors in seven breeding colonies in Extremadura (SW Iberian Peninsula). Using a Geographic Information System and multivariate models, we analyzed the relationship of breeding success with anthropic and natural factors at the nest site and in the foraging area of the adults. We incorporated into the models density-dependent effects between pairs and the spatial autocorrelation of the environmental variables. The differences in breeding success resulted from spatial variations in natural and anthropic conditions, with present human disturbance to nests and future alteration of climate having an expected negative effect at all the sites. Management measures must set calendar restrictions for the immediate environment of the nests, mainly with respect to forestry and hunting activities. A second key element is the protection of the habitats at the nest sites and in their surrounding area, with the aim of there being both wooded areas available for the location of the nest and open environments for the availability of food. The Special Protection Areas showed a partial effectiveness of conservation measures for the species, and the need for future improvement. Lastly, in a scenario of global warming, management policies with respect to nesting habitats will have to be extended to higher altitude zones, actions that should be guided by the study of the selection of potential nesting habitat. (c) 2005 Elsevier Ltd. All rights reserved.
Screening for high-temperature tolerant cotton cultivars by testing in vitro pollen germination, pollen tube growth and boll retention
Liu, Z Yuan, YL Liu, SQ Yu, XN Rao, LQ
JOURNAL OF INTEGRATIVE PLANT BIOLOGY 48:6 706-714
With radical global climate change and global warming, high temperature stress has become one of major factors exerting a major influence on crop production. In the cotton (Gossypium hirsutum L.)-growing areas of China, especially in the Yangtze River valley, unexpected periodic episodes of extreme heat stress usually occur in July and August, the peak time of cotton flowering and boll loading, resulting in lower boll set and lint yield. Breeding programs for screening high temperature-tolerant cotton germplasm and cultivars are urgent in order to stabilize yield in the current and future warmer weather conditions. In the present study, 14 cotton cultivars were quantified for in vitro pollen germination and pollen tube growth in response to temperatures ranging from 10 to 50 degrees C at 5 degrees C intervals. Different cotton genotypes varied in their in vitro pollen germination and pollen tube length responses to the different temperatures. Maximum pollen germination and pollen tube length ranged from 25.2% to 56.2% and from 414 to 682 mu m, respectively. The average cardinal temperatures (T-min, T-opt, and T-max) also varied among the 14 cultivars and were 11.8, 27.3, and 42.7 degrees C for pollen germination and 11.8, 27.8, and 44.1 degrees C for maximum pollen tube length. Variations in boll retention and boll numbers per plant in field experiments were found for the 14 cotton cultivars and the boll retention and boll retained per plant on 20 August varied considerably in different years according to weather conditions. Boll retention on 20 August was highly correlated with maximum pollen germination (R-2= 0.84) and pollen tube length (R-2=0.64). A screening method based on principle component analysis of the combination of pollen characteristics in an in vitro experiment and boll retention testing in the field environment was used in the present study and, as a result, the 14 cotton cultivars could be classified as tolerant, moderately tolerant, moderately susceptible and susceptible to high temperature.
Dynamical controls on estuarine bathymetry: Assessment against UK database
ESTUARINE COASTAL AND SHELF SCIENCE 68:1-2 282-288
New theories for estuarine bathymetry provide formulations for: (1) depth at the mouth, D versus river flow, Q; (2) tidal intrusion length L versus D and Z (tidal amplitude) and (3) a zone of morphological existence, delineated on a framework of Z versus D. Here, these theories are assessed against a database for 80 UK estuaries. Overall there is good agreement between theory and observations for the sizes and shapes of estuaries classified as either ‘Coastal Plain’ or ‘Bar Built’. Likewise, most estuaries are shown to lie within the theoretical ‘zone of bathymetric existence’. These encouraging agreements enable the theories to be used to: (1) enhance our understanding of existing morphologies, (2) identify anomalous estuaries and (3) make future predictions regarding likely impacts from global climate change and related management scenarios. Subsequent examination of regional historical patterns of morphological evolution, introducing detailed local knowledge, should help to explain these anomalies and refine the new theories. By 2100, we anticipate changes in UK estuaries due to (‘precautionary’) projected 25 % changes in river flow of: Order (0.5 -5 km) in lengths and Order (50-250 m) in breadths. Corresponding changes due to a projected sea level rise of 50 cm are increases in both lengths of Order (1-2.5 km) and breadths of Order (70-100 m). In both cases, the bigger changes will occur in larger estuaries. (c) 2006 Elsevier Ltd. All rights reserved.
Effects of warming conditions in eastern North American forests on red-backed salamander morphology
Gibbs, JP Karraker, NE
CONSERVATION BIOLOGY 20:3 913-917
Several studies have reported climate-associated changes in phenotypicalty plastic traits of amphibians, yet it remains unknown whether amphibians can manifest an evolutionary response to global climate change at the rate and magnitude that it is occurring. To assess this issue, we examined temporal change in the morphology of the red-backed salamander (Plethodon cinereus), a small, abundant woodland salamander distributed widely in eastern North America with two distinct morphotypes: striped individuals associated with cooler microclimates and unstriped individuals associated with warmer microclimates. We compiled morph, frequencies for 50,960 individual salamanders from 558 sites as recorded in the published literature and in unpublished field notes of herpetologists between 1908 and 2004. We observed that striping probability increased with increasing latitude, longitude, and elevation and decreased (from 80% to 74% range wide) with time. The combined forces of regional climate warming and, particularly, forest disturbance have evidently been sufficient to cause morphological evolution in this amphibian over the last century.
North American prairie wetlands are important nonforested land-based carbon storage sites
Euliss, NH Gleason, RA Olness, A McDougal, RL Murkin, HR Robarts, RD Bourbonniere, RA Warner, BG
SCIENCE OF THE TOTAL ENVIRONMENT 361:1-3 179-188
We evaluated the potential of prairie wetlands in North America as carbon sinks. Agricultural conversion has resulted in the average loss of 10.1 Mg ha(-1) of soil organic carbon on over 16 million ha of wetlands in this region. Wetland restoration has potential to sequester 378 Tg of organic carbon over a 10-year period. Wetlands can sequester over twice the organic carbon as no-till cropland on only about 17% of the total land area in the region. We estimate that wetland restoration has potential to offset 2.4% of the annual fossil CO2 emission reported for North America in 1990. (c) 2005 Elsevier B.V. All rights reserved.
Past hydrological events related to understanding global change: An ICSU research project
Gregory, KJ Benito, G Dikau, R Golosov, V Jones, AJJ Macklin, MG Parsons, AJ Passmore, DG Poesen, J Starkel, L Walling, DE
CATENA 66:1-2 2-13
Despite general agreement that global climate change is taking place there is less consensus about the consequences and impacts that may arise. The possibility of greater climatic variability, with changes in the incidence of particular types of events, requires multidisciplinary research so that associated impacts can be considered when devising environmental management strategies. Past hydrological events investigated using palaeoenvironmental techniques, over time periods longer than the period of continuous records, are a possible source of information to complement monitored records. Six international research groups (GLOCOPH Commission of INQUA, Water Sustainability Commission of IGU, LUCIFS in IGBP-PAGES, Geomorphic Challenges for the 21st Century Commission of IGU, International Commission on Continental Erosion of IAHS, and Fluvial Archives Group [FLAG] associated with INQUA and IGU) have each contributed results from their specific time and spatial scales in integrated research collaboration. Relevant research conclusions have been combined and a research project under-taken which is the subject of four later papers. A provisional protocol for use of past hydrological events in order to understand global change is proposed and adapted in the final paper, to take account of other papers included and contributions to the discussions. (c) 2005 Elsevier B.V. All rights reserved.
Terminal Pleistocene braided to meandering transition in rivers of the Southeastern USA
CATENA 66:1-2 155-160
Thirteen paleomeanders on the oldest parts of meander belts on floodplains in the Coastal Plain of Georgia and the Carolinas (southeastern USA) were selected for radiocarbon dating to determine the onset of meandering following braiding during the Late Pleistocene during Oxygen Isotope Stage 2. The radiocarbon ages were compared to previously reported Late Pleistocene ages for braid bars and eolian dunes. Results indicate that meandering commenced at circa 15,000 to 16,000 cal years BP and continued throughout the terminal Pleistocene and Holocene. Correlation with other paleoenvironmental records indicates that this shift to meandering was associated with global warming and moister conditions in the Southeastern United States that led to a denser vegetation cover and a reduction in sediment yield. The shift to meandering was also associated with some incision and terracing of the Late Pleistocene braided fluvial surfaces. Paleodischarge of the bankfull condition of early Holocene meandering channels was apparently greater than under modem conditions, suggesting wetter conditions at that time than at present. This braided to meandering transition in the southeastern United States provides an example of river response to global climate change in a relatively low latitude region of the world that was not influenced by glacial or periglacial landscape conditions. (c) 2005 Elsevier B.V. All rights reserved.
Late Pliocene vegetation and climate in Namibia (southern Africa) derived from palynology of ODP Site 1082
GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS 7: -
[ 1] The present-day condition of bipolar glaciation characterized by rapid and large climate fluctuations began at the end of the Pliocene with the intensification of the Northern Hemisphere continental glaciations. The global cooling steps of the late Pliocene have been documented in numerous studies of Ocean Drilling Program (ODP) sites from the Northern Hemisphere. However, the interactions between oceans and between land and ocean during these cooling steps are poorly known. In particular, data from the Southern Hemisphere are lacking. Therefore I investigated the pollen of ODP Site 1082 in the southeast Atlantic Ocean in order to obtain a high-resolution record of vegetation change in Namibia between 3.4 and 1.8 Ma. Four phases of vegetation development are inferred that are connected to global climate change. ( 1) Before 3 Ma, extensive, rather open grass-rich savannahs with mopane trees existed in Namibia, but the extension of desert and semidesert vegetation was still restricted. ( 2) Increase of winter rainfall dependent Renosterveld-like vegetation occurred between 3.1 and 2.2 Ma connected to strong advection of polar waters along the Namibian coast and a northward shift of the Polar Front Zone in the Southern Ocean. ( 3) Climatically induced fluctuations became stronger between 2.7 and 2.2 Ma and semiarid areas extended during glacial periods probably as the result of an increased pole-equator thermal gradient and consequently globally enhanced atmospheric circulation. ( 4) Aridification and climatic variability further increased after 2.2 Ma, when the Polar Front Zone migrated southward and the influence of Atlantic moisture brought by the westerlies to southern Africa declined. It is concluded that the positions of the frontal systems in the Southern Ocean which determine the locations of the high-pressure cells over the South Atlantic and the southern Indian Ocean have a strong influence on the climate of southern Africa in contrast to the climate of northwest and central Africa, which is dominated by the Saharan low-pressure cell.
Climate agreements based on responsibility for global warming: Periodic updating, policy choices, and regional costs
Rive, N Torvanger, A Fuglestvedt, JS
GLOBAL ENVIRONMENTAL CHANGE-HUMAN AND POLICY DIMENSIONS 16:2 182-194
It has been suggested that calculations of historical responsibility for global warming should be used to distribute mitigation requirements in future climate agreements. For a medium-term mitigation scenario, we calculate regional mitigation costs resulting from global allocation schemes based on the Brazilian Proposal that solely incorporate historical responsibility as a burden sharing criterion. We find that they are likely to violate ability-to-pay principles. In spite of less stringent abatement requirements, developing country regions experience cost burdens (as a percentage of GDP) in the same range as those of developed countries. We also assess the policy options available for calculating historical responsibility. The periodic updating of responsibility calculations over time, concerns over the robustness and availability of emissions data, and the question of whether past emissions were knowingly harmful, may lead to policy choices that increase the relative historical responsibility attributed to developing countries. This, in turn, would increase their mitigation cost burden. (C) 2006 Elsevier Ltd. All rights reserved.
Simulating the effects of temperature on individual and population growth of Rhinoptera bonasus: a coupled bioenergetics and matrix modeling approach
Neer, JA Rose, KA Cortes, E
MARINE ECOLOGY-PROGRESS SERIES 329: 211-223
Cownose rays Rhinoptera bonasus typify the K-selected life history strategy that makes their population dynamics susceptible to variation in natural and anthropogenic factors. We used an individual-based bioenergetics model, coupled to a matrix projection model, to predict how water temperatures warmer and cooler than current conditions would affect the individual growth and the population dynamics of cownose rays. The bioenergetics model simulated the daily growth, survival, and reproductive output of a cohort of female individuals from birth over their lifetime. Warmer and cooler temperature scenarios under alternative assumptions about ray movement were simulated. Under warmer conditions, daily consumption rate would have to increase by about 12 % or weights-at-age would decrease by 10 to 17 %, while under cooler conditions, daily consumption would have to decrease by about 14% or weights-at-age would increase by about 15%. Slowed individual growth under warmer water temperatures translated into slowed population growth rate, decreased net reproductive rate, longer generation time, and higher but delayed age-specific reproductive values. For example, under the scenario that resulted in the slowest individual growth rates, the population growth rate would decrease from 0.027 to 0.005 yr(-1). Population growth rates were more sensitive to variation in survival rates, especially those of mature age-classes, than to fertility rates. Our coupling of an individual-based bioenergetics model with a matrix projection model offers a potentially powerful approach for relating how, with limited to moderate information, changes in environmental variables and habitat that affect individual growth can be expressed as population-level responses.
Effects of aphid herbivory on biomass and leaf-level physiology of Solanum dulcamara under elevated temperature and CO2
Flynn, DFB Sudderth, EA Bazzaz, FA
ENVIRONMENTAL AND EXPERIMENTAL BOTANY 56:1 10-18
Forecasted increases in atmospheric CO2 and global mean temperature are likely to influence insect-plant interactions. Plant traits important to insect herbivores, such as nitrogen content, may be directly affected by elevated CO2 and temperature, while insect herbivores are likely to be directly affected only by temperature. This study investigates changes in the effects of herbivory by the aphid Macrosiphum euphorbiae (Homoptera: Aphididae) on the C-3 perennial Solanum dulcamara under two conditions of atmospheric CO2 concentration (350/750ppm) and three temperature treatments (20/15, 23/18, 26/21 degrees C; day/night temperatures). Plants were grown in glass-topped chambers and initially infested with three apterous, adult aphids. Aphid population size, leaf photosynthetic capacity, carbon to nitrogen (C:N) ratio, specific leaf area, plant height, and total plant biomass were measured after 3 weeks of infestation. Aphid herbivory reduced photosynthetic capacity under all conditions, and resulted in smaller leaf C:N ratios. Aphid populations did not change significantly under elevated CO2, but tended to increase slightly. Average aphid weight decreased at high temperatures. Plant height and biomass were not significantly affected by the CO2 treatment, but growth rates before infestation were enhanced by elevated CO2. These results indicate that the combined effects of both elevated CO2 and temperature may exacerbate aphid damage to certain plants, particularly to plants which respond weakly to increases in atmospheric CO2. Modifications of plant physiology under altered CO2 and temperature do not impair, and may slightly enhance aphid population growth. (c) 2004 Elsevier B.V. All rights reserved.
Modelling responses of pine savannas to climate change and large-scale disturbance
Beckage, B Gross, LJ Platt, WJ
APPLIED VEGETATION SCIENCE 9:1 75-82
Global warming can potentially influence ecological communities through altered disturbance regimes in addition to increased temperatures. We investigate the response of pine savannas in the southeastern United States to global warming using a simple Lotka-Volterra competition model together with predicted changes to fire and hurricane disturbance regimes with global climate change. In the southeastern United States, decreased frequency of both fires and hurricanes with global warming will shift pine savannas toward a forested state. A CO2 fertilization effect that increases the growth rate of tree populations will also push southeastern landscapes from open savannas towards closed forests. Transient dynamics associated with climate driven changes in vegetation will last on the order of decades to a century. In our model, the sensitivity of savannas to relative changes in the frequency of fire versus hurricanes is linearly dependent on the growth rate and mortality of trees in fire and hurricane disturbances.
Climatic variability in the southwest Pacific during the Last Termination (20-10 kyr BP)
Turney, CSM Kershaw, AP Lowe, JJ van der Kaars, S Johnston, R Rule, S Moss, P Radke, L Tibby, J McGlone, MS Wilmshurst, JM Vandergoes, MJ Fitzsimons, SJ Bryant, C James, S Branch, NP Cowley, J Kalin, RM Ogle, N Jacobsen, G Fifield, LK
QUATERNARY SCIENCE REVIEWS 25:9-10 886-903
The degree to which palaeoclimatic changes in the Southern Hemisphere co-varied with events in the high latitude Northern Hemisphere during the Last Termination is a contentious issue, with conflicting evidence for the degree of ‘teleconnection’ between different regions of the Southern Hemisphere. The available hypotheses are difficult to test robustly, however, because there are few detailed palaeoclimatic records in the Southern Hemisphere. Here we present climatic reconstructions from the southwestern Pacific, a key region in the Southern Hemisphere because of the potentially important role it plays in global climate change. The reconstructions for the period 20-10 kyr BP were obtained from five sites along a transect from southern New Zealand, through Australia to Indonesia, supported by 125 calibrated C-14 ages. Two periods of significant climatic change can be identified across the region at around 17 and 14.2 cal kyr BP, most probably associated with the onset of warming in the West Pacific Warm Pool and the collapse of Antarctic ice during Meltwater Pulse-1A, respectively. The severe geochronological constraints that inherently afflict age models based on radiocarbon dating and the lack of quantified climatic parameters make more detailed interpretations problematic, however. There is an urgent need to address the geochronological limitations, and to develop more precise and quantified estimates of the pronounced climate variations that clearly affected this region during the Last Termination. (c) 2005 Elsevier Ltd. All rights reserved.
Post-Eocene climate change, niche conservatism, and the latitudinal diversity gradient of New World birds
Hawkins, BA Diniz, JAF Jaramillo, CA Soeller, SA
JOURNAL OF BIOGEOGRAPHY 33:5 770-780
Aim The aim of this study was to test a variant of the evolutionary time hypothesis for the bird latitudinal diversity gradient derived from the effects of niche conservatism in the face of global climate change over evolutionary time. Location The Western Hemisphere. Methods We used digitized range maps of breeding birds to estimate the species richness at two grain sizes, 756 and 12,100 km(2). We then used molecular phylogenies resolved to family to quantify the root distance (RD) of each species as a measure of its level of evolutionary development. Birds were classified as ‘basal’ or ‘derived’ based on the RD of their family, and richness patterns were contrasted for the most basal and most derived 30% of species. We also generated temperature estimates for the Palaeogene across the Western Hemisphere to examine how spatial covariation between past and present climates might make it difficult to distinguish between ecological and evolutionary hypotheses for the current richness gradient. Results The warm, wet tropics support many species from basal bird clades, whereas the northern temperate zone and cool or dry tropics are dominated by species from more recent, evolutionarily derived clades. Furthermore, crucial to evaluating how niche conservatism among birds may drive the hemispherical richness gradient, the spatial structure of the richness gradient for basal groups is statistically indistinguishable from the overall gradient, whereas the richness gradient for derived groups is much shallower than the overall gradient. Finally, modern temperatures and the pattern of climate cooling since the Eocene are indistinguishable as predictors of bird species richness. Main conclusions Differences in the richness gradients of basal vs. derived clades suggest that the hemispherical gradient has been strongly influenced by the differential extirpation of species in older, warm-adapted clades from parts of the world that have become cooler in the present. We propose that niche conservatism and global-scale climate change over evolutionary time provide a parsimonious explanation for the contemporary bird latitudinal diversity gradient in the New World, although dispersal limitation of some highly derived clades probably plays a secondary role.
Conservation and restoration of the Pinus palustris ecosystem
Gilliam, FS Platt, WJ
APPLIED VEGETATION SCIENCE 9:1 7-10
The well-documented decline of the Pinus palustris ecosystem has resulted from several anthropogenic influences, such as forest clearing (e.g. pine plantation forestry, agriculture) and urban development, both of which are closely related to increases in human populations. Other impacts have arisen from alterations in disturbance regimes responsible for maintaining the structure and function of these ecosystems. Restoration and management of degraded pine savanna ecosystems is critical. Identification of ecological processes that determine the structure and function of the intact system are important because successful restoration efforts should be based on sound scientific understanding. In this paper, we introduce this special issue on the ecology, conservation, and restoration of the Pinus palustris ecosystem. Some global climate change scenarios have suggested that future changes may occur that alter frequency and severity of disturbances such as fires and hurricanes. Such changes may have large effects on pine stands, and ultimately entire Pinus palustris savanna ecosystems, thus presenting further challenges to their sustainable management.
Reduction processes in forest wetlands: Tracking down heterogeneity of source/sink functions with a combination of methods
Paul, S Kusel, K Alewell, C
SOIL BIOLOGY & BIOCHEMISTRY 38:5 1028-1039
Wetlands are considered to be the biggest unknowns regarding the influence of global climate change on element dynamics, so knowledge of processes and conditions controlling sink and source functions of redox processes is crucial. The aim of this study was to investigate the sink/source function of nitrate, Fe, sulfate reduction and methanogenesis of an upland and a lowland fen within a boreal spruce catchment, southern Germany. We used suction cups and anaerobic dialysis chambers for soil solution sampling, FeS probes for the determination of S oxidation potential and stability of anoxic conditions and analysis of the soil solid phase (contents of C, S and Fe species). Both fens had high rates of nitrate reduction and potentially high rates of CH4 production. The upper few cm of all profiles were oxic with low CH4 concentrations, suggesting low CH4 emission rates from the soil, though emission by vascular plants cannot be excluded. Sulfate and Fe reduction processes differed significantly in the fens. The upland fen was characterized by relatively stable anoxic conditions, low Fe contents but high contents of organic S and low C/S ratios. We concluded that the upland fen is an effective sink for sulfate with long-term S storage. In contrast, the lowland fen was characterized by alternating oxidation-reduction cycles with high Fe contents, lower contents of organic S and higher C/S ratios. Thus, even though low sulfate and high Fe concentrations in soil solutions indicated high reduction rates in the lowland fen, long-term storage of S is not likely in this fen. Differences in biogeochemical processes between sites are most likely not associated with hydrology but rather with the role of vascular plants. (c) 2005 Elsevier Ltd. All rights reserved.
Natural disturbances and the physiognomy of pine savannas: A phenomenological model
Gilliam, FS Platt, WJ Peet, RK
APPLIED VEGETATION SCIENCE 9:1 83-96
Question: The decline of the Pinus palustris ecosystems has resulted from anthropogenic influences, such as conversion to pine plantation forestry, agriculture and land development, all of which are closely related to increases in human populations. Other effects, however, have arisen from alterations in disturbance regimes that maintain the structure and function of these ecosystems. How have alterations of the disturbance regime altered the physiognomy of ‘old-growth’ stands, and what are the implications for ecosystem conservation and restoration? Methods: In contrast to models that emphasize close interactions among the vertically complex strata, we develop a conceptual phenomenological model for the physiognomic structure of Pinus palustris stands. We relate two natural disturbances (tropical storms and fire) that affect different stages of the life cycle to different aspects of the physiognomic structure. We then compare overstorey stand structure and ground cover composition of two old-growth longleaf stands near the extremes of different composite disturbance regimes: the Wade Tract (frequent hurricanes and fire) and the Boyd Tract (infrequent hurricanes and long-term fire exclusion). Results: We predict that tropical storms and fires have different effects on stand physiognomy. Tropical storms are periodic, and sometimes intense, whereas fires are more frequent and less intense. Hurricanes directly influence the overstorey via wind-caused damage and mortality, and indirectly influence the herb layer by altering the spatial distribution of shading and litter accumulation. Fire exerts direct effects on juvenile stages and indirect effects on the herb layer via fine fuel consumption and selective mortality of potential competitors of P. palustris juveniles. These differences in effects of disturbances can result in widely different physiognomies for P. palustris stands. Finally, some global climate change scenarios have suggested that changes may occur in tropical storm and fire regimes, altering frequency and severity. Such changes may greatly affect pine stands, and ultimately entire pine savanna ecosystems. Conclusions: Our phenomenological model of disturbance regimes in Pinus palustris old-growth produces very different physiognomies for different disturbances regimes that reflect natural process and human management actions. This model can be used to derive restoration strategies for pine savannas that are linked to reinstitution of important ecological processes rather than specific physiognomic states.
Calibrating remotely sensed chlorophyll-a data by using penalized regression splines
Clarke, ED Speirs, DC Heath, MR Wood, SN Gurney, WSC Holmes, SJ
JOURNAL OF THE ROYAL STATISTICAL SOCIETY SERIES C-APPLIED STATISTICS 55: 331-353
The distribution and biomass of phytoplankton in the upper layers of the ocean are important indicators of productivity and carbon cycling. Large scale perturbations in phytoplankton are linked to global climate change, so accurate monitoring is increasingly important. The chlorophyll-a pigment concentration in the water is routinely measured as an index of algal biomass. Direct water sampling from ships and moorings provides accurate data, but woefully poor spatial and temporal coverage of the oceans. In contrast, multispectral sea surface reflectance data from orbiting satellite-borne sensors, which in principle can be used to derive pigment concentration, give the prospect of globally detailed spatial and temporal coverage. Unfortunately, there are some locally variable confounding factors, which the algorithms for converting reflectance data to ocean chlorophyll-a concentration do not take into account. Hence, statistical methods are needed to obtain accurate predictions of chlorophyll-a. concentration by using data from both these sources. We use penalized regression splines to model water sample data as a three-dimensional function of satellite measurements, seabed depth and time of year. The models are effectively complex calibrations of the satellite data against the bottle data. We compare the results by using thin plate regression splines and tensor product splines using generalized cross-validation to choose the relative amounts of smoothing for each of the covariates. Since the thin plate spline penalty functional is isotropic, this requires the introduction of two scaling parameters, which are also chosen by generalized cross-validation, to scale the covariates relatively to one another. The tensor product spline smooths each covariate appropriately by use of separate smoothing parameters for each covariate. The models are tested by application to data from the north-east Atlantic, first randomly subsampling the data to achieve even coverage over the entire region. Both approaches perform equally well, achieving R-2 approximate to 65%, both for the data that are used to fit the model and for a validation data set. Of particular concern in this application is that monthly predictions from the models should be biologically plausible over the whole region, describing the broad regional features that are apparent in the satellite data and extrapolating sensibly where satellite data are not available. To achieve this, the satellite data must be one of the covariates in the model; spatiotemporal covariates alone are not sufficient to extrapolate sensibly into areas where no data are available.
Coastal processes and morphological change in the Dunwich-Sizewell area, Suffolk, UK
Pye, K Blott, SJ
JOURNAL OF COASTAL RESEARCH 22:3 453-473
The Suffolk coast around Dunwich and Sizewell has experienced major changes during the past 2000 years, with significant loss of land caused by marine erosion. Against a background of projected acceleration in sea level rise and storminess resulting from global climate change, concern has been expressed that present coastal defences may become unsustainable in the medium to longer term, and that the survival of internationally important wildlife habitats is under threat. This paper examines the past coastal evolution in the light of natural processes, and provides a discussion of future management options. Based on analysis of historical maps, charts, air photographs, and ground survey data, it is shown that rates of coastal erosion have actually been much lower in the last 50 years than historically, and at present there is little scientific evidence to support a case for large-scale managed realignment or abandonment of flood and coastal defences. However, in some areas, notably the very northern end of the Minsmere barrier and the middle part of the Dunwich-Walberswick barrier, local realignment and/or construction of stronger secondary flood defences are required to establish a coastal condition that is more in equilibrium with current processes, and to provide adequate protection against marine flooding even under present climatic and sea level conditions.
Impact of climate change on the regional hydrology - Scenario-based modelling studies in the German Rhine catchment
Menzel, L Thieken, AH Schwandt, D Burger, G
NATURAL HAZARDS 38:1-2 45-61
The aim of the study is an impact analysis of global climate change on regional hydrology with special emphasis on discharge conditions and floods. The investigations are focussed on the major part of the German Rhine catchment with a drainage area of approx. 110,000 km(2). This area is subdivided into 23 subcatchments. In a first step, the hydrological model HBV-D serves to simulate runoff conditions under present climate for the individual subbasins. Simulated, large scale atmospheric fields, provided by two different Global Circulation Models (GCMs) and driven by the emission scenario IS95a (“business as usual”) are then used as input to the method of expanded downscaling (EDS). EDS delivers local time series of scenario climate as input to HBV-D. In a final step, the investigations are focussed on the assessment of possible future runoff conditions under the impact of climate change. The study indicates a potential increase in precipitation, mean runoff and flood discharge for small return intervals. However, the uncertainty range that originates from the application of the whole model chain and two different GCMs is high. This leads to high cumulative uncertainties, which do not allow conclusions to be drawn on the development of future extreme floods.
Land cover change and its impacts on soil C and N in two watersheds in the center of the Qinghai-Tibetan Plateau
Wang, GX Wang, YB Qian, J Wu, QB
MOUNTAIN RESEARCH AND DEVELOPMENT 26:2 153-162
The responses of the ecosystems along the 0 degrees C mean annual isotherm to global climate change are intense and involve significant changes in land cover at the water shed scale. This paper evaluates changes in land cover in the center of Qinghai-Tibet, the headwater region of the Yangtze and Yellow Rivers, on the basis of two sets of remote sensing data (1986 and 2000) and field investigations. Over a period of 15 years, 23% and 34% of alpine cold swamp were recently turned into alpine cold meadow or alpine cold steppe, and decreased in area by 25.9% and 42.7% in the headwater areas of the Yellow and Yangtze Rivers, respectively. Moreover, more than 20% of high-coverage alpine cold meadow and alpine cold steppe were converted to lower-coverage alpine cold meadow (vegetation coverage > 80%) and alpine cold steppe (vegetation coverage > 50%). Desertified land increased by 18.4% (bare rocks and sparse land) and 31.1% (sandy land) in the headwater area of the Yellow River and by 17.8%-18.5% in the headwater area of the Yangtze River. Land cover change in this region involves a complex transition between land cover types, which have a great influence on soil nutrients and the soil organic carbon (SOC) pool. Land cover changes in the study area over the 15-year study period led to the loss of 336.6 Gg of SOC, of which 61.6% were lost by alpine cold swamp transformation, and a total nitrogen (N) loss of 26.9 Gg, of which 81.9% occurred in the headwater area of the Yangtze River. The changes in the carbon and nitrogen cycles have serious implications for greenhouse gas emissions due to land cover change caused by climate warming in the Qinghai-Tibetan Plateau.
Modeling generator power plant portfolios and pollution taxes in electric power supply chain networks: A transportation network equilibrium transformation
Wu, K Nagurney, A Liu, ZG Stranlund, JK
TRANSPORTATION RESEARCH PART D-TRANSPORT AND ENVIRONMENT 11:3 171-190
Global climate change and fuel security risks have encouraged international and regional adoption of pollution/carbon taxes. A major portion of such policy interventions is directed at the electric power industry with taxes applied according to the type of fuel used by the power generators in their power plants. This paper proposes an electric power supply chain network model that captures the behavior of power generators faced with a portfolio of power plant options and subject to pollution taxes. We demonstrate that this general model can be reformulated as a transportation network equilibrium model with elastic demands and qualitatively analyzed and solved as such. The connections between these two different modeling schemas is done through finite-dimensional variational inequality theory. The numerical examples illustrate how changes in the pollution/carbon taxes affect the equilibrium electric power supply chain network production outputs, the transactions between the various decision-makers the demand market prices, as well as the total amount of carbon emissions generated. (c) 2006 Elsevier Ltd. All rights reserved.
Effects of river discharge, temperature, and future climates on energetics and mortality of adult migrating Fraser River sockeye salmon
Rand, PS Hinch, SG Morrison, J Foreman, MGG MacNutt, MJ Macdonald, JS Healey, MC Farrell, AP Higgs, DA
TRANSACTIONS OF THE AMERICAN FISHERIES SOCIETY 135:3 655-667
We evaluated the effects of past and future trends in temperature and discharge in the Fraser River on the migratory performance of the early Stuart population of sockeye salmon Oncorhynchus nerka. Fish of lower condition exhibited disproportionately higher mortality during the spawning run, elucidating a critical link between energetic condition and a fish’s ability to reach the spawning grounds. We simulated spawning migrations by accounting for energetic demands for an average individual in the population from the time of entry into the Fraser River estuary to arrival on the spawning grounds (about 1,200 km upstream) and estimated energy expenditures for the average migrant during 1950-2001. The model output indicates relatively high interannual variability in migration energy use and a marked increase in energy demands in recent years related to unusually high discharges (e.g., 1997) and warmer than average water temperature (e.g., 1998). We examined how global climate change might effect discharge, water temperature, and the energy used by sockeye salmon during their spawning migration. Expected future reductions in peak flows during freshets markedly reduced transit time to the spawning ground, representing a substantial energy savings that compensated for the effect of the increased metabolic rate resulting from exposure to warmer river temperatures. We suggest that such watershed-scale compensatory mechanisms may be critical to the long-term sustainability of Pacific salmon, given expected changes in climate. However, such compensation will probably only be applicable to some stocks and may be limited under extremely high temperatures where nonenergetic factors such as disease and stress may play a more dominant role in defining mortality. Our results further indicate that a long-term decline in the mean mass of adult sockeye salmon completing their marine residency could erode their migratory fitness during the river migration and hence jeopardize the sustainability of sockeye salmon and the fishery that targets them.
Modelling climate-change impacts on stream temperature of Formosan landlocked salmon habitat
Tung, CP Lee, TY Yang, YC
HYDROLOGICAL PROCESSES 20:7 1629-1649
A physics-based model is provided for predicting the impact of climate change on stream temperature and, in turn, on Formosan landlocked salmon (Oncorhynchus masou formosanus) habitat. Because upstream watersheds on Taiwan Island are surrounded with hi-h and steep mountains, the influence of mountain shading on solar radiation and longwave radiation is taken into account by using a digital elevation model. Projections using CGCM2 and HADCM3 models and CCCM and GISS models provided information on future climatic conditions. The results indicate that annual average stream temperatures may rise by 0.5 degrees C (HADCM3 short term) to 2.9 degrees C (CGCM2 long term) due to climate change. The simulation results also indicate that the average suitable habitat for the Formosan landlocked salmon may decline by 333 m (HADCM3 short term) to 1633 m (CGCM2 long term) and 166 m (HADCM3 short term) to 1833 m (CGCM2 long term) depending on which thermal criterion (17 degrees C and 18 degrees C respectively) is applied. The results of this study draw attention to the tasks of Formosan landlocked salmon conservation agencies, not only with regard to restoration plans of the local environment, but also to the mitigation strategies to global climate change that are necessary and require further research. Copyright (c) 2005 John Wiley & Sons, Ltd.
Element interactions limit soil carbon storage
van Groenigen, KJ Six, J Hungate, BA de Graaff, MA van Breemen, N van Kessel, C
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA 103:17 6571-6574
Rising levels of atmospheric CO2 are thought to increase C sinks in terrestrial ecosystems. The potential of these sinks to mitigate CO2 emissions, however, may be constrained by nutrients. By using metaanalysis, we found that elevated CO2 only causes accumulation of soil C when N is added at rates well above typical atmospheric N inputs. Similarly, elevated CO2 only enhances N-2 fixation, the major natural process providing soil N input, when other nutrients (e.g., phosphorus, molybdenum, and potassium) are added. Hence, soil C sequestration under elevated CO2 is constrained both directly by IN availability and indirectly by nutrients needed to support N2 fixation.
Projected changes in the Caspian Sea level for the 21st century based on the latest AOGCM simulations
Elguindi, N Giorgi, F
GEOPHYSICAL RESEARCH LETTERS 33:8 -
We use output from global climate change simulations with seven Atmosphere-Ocean General Circulation Models (AOGCMs) to assess possible changes in Caspian Sea basin hydrologic budget and corresponding changes in the Caspian Sea Level (CSL) for the 21st century under different greenhouse gas (GHG) emission scenarios (A1b and A2). Although most models project an increase in precipitation over the Volga river basin, where most of the runoff into the Caspian Sea is generated, a steady decline in the CSL is mostly estimated. This is due to large increases in evapotranspiration over land and over the Caspian Sea surface. By the end of the 21st century, the ensemble average of the model-based estimates suggest a 9 meter drop in the CSL for both scenarios analyzed. This could be potentially devastating for the surrounding region if no adaptation or mitigation measures are taken.
Antarctic birds breed later in response to climate change
Barbraud, C Weimerskirch, H
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA 103:16 6248-6251
In the northern hemisphere, there is compelling evidence for climate-related advances of spring events, but no such long-term biological time series exist for the southern hemisphere. We have studied a unique data set of dates of first arrival and laying of first eggs over a 55-year period for the entire community of Antarctic seabirds in East Antarctica. The records over this long period show a general unexpected tendency toward later arrival and laying, an inverse trend to those observed in the northern hemisphere. Overall, species now arrive at their colonies 9.1 days later, on average, and lay eggs an average of 2.1 days later than in the early 1950s. Furthermore, these delays are linked to a decrease in sea ice extent that has occurred in eastern Antarctica, which underlies the contrasted effects of global climate change on species in Antarctica.
A new study of the Mediterranean outflow, air-sea interactions, and meddies using multisensor data
Yan, XH Jo, YH Liu, WT He, MX
JOURNAL OF PHYSICAL OCEANOGRAPHY 36:4 691-710
Previous studies of the Mediterranean Sea outflow and meddies (O&M) were limited by the poor spatial and temporal resolution of conventional in situ observations as well as the confinement of satellite observations to the ocean’s surface. Accordingly, little is known about the formation and transport of meddies and the spatial and temporal variation of O&M trajectories, which are located, on average, at a depth of 1000 m. However, a new remote sensing method has been developed by the authors to observe and study the O&M through unique approaches in satellite multisensor data integration analyses. Satellite altimeter, scatterometer, infrared satellite imagery, and XBT data were used to detect and calculate the trajectories and the relative transport of the O&M (January 1993-December 2002). Two experiments [covering 199395: A Mediterranean Undercurrent Seeding Experiment (AMUSE) and Structures des Echanges MerAtmosphere, Proprietes des Heterogeneites Oceaniques: Recherche Experimentale (SEMAPHORE)] and XBT temperature measurements were used to directly validate the method presented herein. The monthly mean features derived from floats and XBTs for multiple meddies and the results of the presented method were significantly correlated based on a statistical chi-square test. In addition, the complex singular value decomposition method was used to identify the propagating features and their phase speeds. It was found that saltier water from the Mediterranean Sea was transported into the North Atlantic Ocean over the Strait of Gibraltar in boreal spring and summer relative to boreal autumn and winter. Streamfunctions using altimetry, and time-frequency energy distributions using the Hilbert-Huang transform, were computed to evaluate the meddy interactions with the sea surface variation. Since the O&M play a significant role in carrying salty water from the Mediterranean Sea into the Atlantic, such new knowledge about their trajectories, transport, and life histories is important to the understanding of their mixing and interaction with North Atlantic water. This may lead to a better understanding of the global ocean circulation and global climate change.
Long-term demographic fluctuations in an orchid species driven by weather: implications for conservation planning
Pfeifer, M Wiegand, K Heinrich, W Jetschke, G
JOURNAL OF APPLIED ECOLOGY 43:2 313-324
1. Management decisions are increasingly based on matrix models intended to predict the long-term fate of endangered species. However, certain elements of these models, such as life-state transition probabilities (vital rates), are difficult to parameterize and their values may vary depending on external conditions such as weather. Details of how weather might influence population performance are rare, yet necessary to assess the effects of global climate change on a species’ distribution. 2. Based on a 26-year data set of a population of Himantoglossum hircinum in a nature reserve in Germany, variations of life-history traits and vital rates were studied. Matrix analysis was used to identify the most important life-state transitions for population growth. Multiple linear regression was used to quantify the response of population traits and vital rates to changing weather conditions. 3. Population size increased exponentially and density effects could not be observed. Flowering plants and large plants had the highest and second highest reproductive value, respectively. The population’s finite rate of increase fluctuated strongly among years; life-history traits varied strongly and were interlinked, thereby violating the assumptions of matrix modelling in a population viability analysis. 4. Some vital rates and the population growth rate showed a trend over the total period. A certain and sometimes large amount of that variability could be attributed to variability of weather conditions, with warmer winter conditions favouring population performance. Prediction of population size was fairly accurate within a time frame of 10 years, but size class structure was not. 5. Synthesis and applications. Matrix modelling proved to be unreliable for predicting long-term population dynamics, despite the long-term data set used for matrix construction. This can be explained by weather-dependent variability of vital rates driving population dynamics. A minimum study period of 4 years is necessary to produce relevant information for model development. Our study emphasizes the need for critical evaluation of management decisions based only on single short-term studies and for studies covering longer time intervals than 2-3 years.
Pied Flycatchers Ficedula hypoleuca travelling from Africa to breed in Europe: differential effects of winter and migration conditions on breeding date
Both, C Sanz, JJ Artemyev, AV Blaauw, B Cowie, RJ Dekhuizen, AJ Enemar, A Javinen, A Nyholm, NEI Potti, J Ravussin, PA Silverin, B Slater, FM Sokolov, LV Visser, ME Winkel, W Wright, J Zang, H
ARDEA 94:3 511-525
In most bird species there is only a short time window available for optimal breeding due to variation in ecological conditions in a seasonal environment. Long-distance migrants must travel before they start breeding, and conditions at the wintering grounds and during migration may affect travelling speed and hence arrival and breeding dates. These effects are to a large extent determined by climate variables such as rainfall and temperature, and need to be identified to predict how well species can adapt to climate change. In this paper we analyse effects of vegetation growth on the wintering grounds and sites en route on the annual timing of breeding of 17 populations of Pied Flycatchers Ficedula hypoleuca studied between 1982-2000. Timing of breeding was largely correlated with local spring temperatures, supplemented by striking effects of African vegetation and NAO. Populations differed in the effects of vegetation growth on the wintering grounds, and on their northern African staging grounds, as well as ecological conditions in Europe as measured by the winter NAO. In general, early breeding populations (low altitude, western European populations) bred earlier in years with more vegetation in the Northern Sahel zone, as well as in Northern Africa. In contrast, late breeding populations (high altitude and northem and eastern populations) advanced their breeding dates when circumstances in Europe were more advanced (high NAO). Thus, timing of breeding in most Pied Flycatcher populations not only depends upon local circumstances, but also on conditions encountered during travelling, and these effects differ across populations dependent on the timing of travelling and breeding.
Carbon flows and carbon use in the German anthroposphere: An inventory
Uihlein, A Poganietz, WR Schebek, L
RESOURCES CONSERVATION AND RECYCLING 46:4 410-429
Today, global climate change is one of the most urgent environmental problems. The atmospheric concentration of carbon dioxide (CO2) has to be stabilised by significant reductions of CO, emissions in the next decades to keep the expected temperature rise within tolerable borders. Efforts exceeding the implemented measures to reduce CO2 emissions in Germany are desirable. An important precondition for such measures is a scientific-based inventory of the sources, sinks, and use of carbon. In this paper, we present CarboMoG, i.e. Carbon Flow Model of Germany. CarboMoG is a carbon flow model covering carbon flows, carbon sources and sinks in Germany and the German anthroposphere, showing concurrent energy and non-energy use of carbon sources. The model consists of seven modules in German anthroposphere following the German classification of economic sectors. Carbon flows to and from atmosphere and lithosphere as well as imports and exports were included into the model. The model comprises roughly 220 material flows determined based on material flow procedures for the base year 2000. Main sources of carbon are fossil energy carriers from lithosphere and uptake Of CO2 by crops (52% resp. 48% of all carbon sources). The model calculations show that import of energy carriers dominates total carbon import to Germany (82%). Total non-energy use of carbon in Germany is significantly higher than energy use (386 Mt C and 230 Mt C, resp.). Carbon throughput of Industry is greatest (about 224 Mt C input), followed by Energy (about 129 Mt C input). Agriculture and Forestry & Industry show the highest figure for non-energy use of carbon, energy use of carbon is largest in the Energy sector. Emissions Of CO2 to atmosphere account for 94% of carbon flows to sinks in Germany. Carbon accumulates in German anthroposphere 5 Mt C in 2000. (c) 2005 Elsevier B.V. All rights reserved.
Climate sensitivity to ocean dimethylsulphide emissions
Gunson, JR Spall, SA Anderson, TR Jones, A Totterdell, IJ Woodage, MJ
GEOPHYSICAL RESEARCH LETTERS 33:7 -
The production of dimethylsulphide (DMS) by ocean phytoplankton is hypothesized to form part of a feedback process on global climate. Changes in the DMS flux to the atmosphere cause changes to aerosols for cloud formation, leading to changes in the amount of radiation reaching the ocean, and hence on the planktonic production of DMS. This hypothesis has been investigated using a coupled ocean-atmosphere general circulation model (COAGCM) that includes an ocean ecosystem model and an atmospheric sulphur cycle. Ocean DMS concentrations are parameterised as a function of chlorophyll, nutrient and light. The results of several sensitivity experiments are presented showing significant global climate change responses to perturbations in ocean DMS production. A small negative feedback from climate change onto ocean DMS production is found and the implications are discussed.
Carbon sequestration in two Brazilian Cerrado soils under no-till
Bayer, C Martin-Neto, L Mielniczuk, J Pavinato, A Dieckow, J
SOIL & TILLAGE RESEARCH 86:2 237-245
A considerable proportion of the 200 million hectares of the Brazilian Cerrado is suitable for annual crops but little is known about the effects of tillage on the C dynamics of Cerrado soils. We evaluated the role of two representative Cerrado Oxisols (350 and 650 g clay kg(-1)) as sources or sinks of atmospheric C when managed under three tillage systems (conventional tillage (CT), reduced tillage (RT), and no-till (NT)) in 8- and 5-year long-term experiments. A literature review was also carried out and the mean C sequestration rates in no-till soils of tropical and subtropical regions of Brazil were calculated and compared with values for soils from temperate regions of the world. The original C stocks in 0-20 cm layer of soils under native Cerrado were higher in the clayey (54.0 Mg ha(-1)) than in the sandy clay loam soil (35.4 Mg ha(-1)), suggesting a higher physical stability of organic matter associated with variable clay minerals in the clayey Oxisol. The original C stocks of the native Cerrado soils appear not to have decreased after 23 years of conventional tillage in the sandy clay loam Oxisol, except when the soil had been subjected to erosion (15% loss of C), or after 25 years in the clayey Oxisol. Compared to conventionally tilled soil, the C stocks in no-till sandy clay loam Oxisol increased by 2.4 Mg ha(-1) (C sequestration rate = 0.30 Mg ha(-1) year(-1)) and in the clayey Oxisol by 3.0 Mg ha(-1) (C sequestration rate = 0.60 Mg ha(-1) year(-1)). The mean rate of C sequestration in the no-till Brazilian tropical soils was estimated to be 0.35 Mg ha(-1) year(-1), similar to the 0.34 Mg ha(-1) year(-1) reported for soils from temperate regions but lower than the 0.48 Mg ha(-1) year(-1) estimated for southern Brazilian subtropical soils. Considering the large area (about 70 million hectares) of the Cerrado which is currently used and potentially available for cropland, the adoption of no-till systems could turn the Cerrado soils into a significant sink for atmospheric C and contribute to the mitigation of global climate change. (C) 2005 Elsevier B.V. All rights reserved.
Migration Watch: an Internet survey to monitor spring migration in Britain and Ireland
Baillie, SR Balmer, DE Downie, IS Wright, KHM
JOURNAL OF ORNITHOLOGY 147:2 254-259
The arrival patterns of summer visitors to Britain and Ireland were monitored from 2002 to 2004 using large numbers of birdwatching lists collected by Migration Watch, an Internet-based survey. Records were only accepted from registered observers, and procedures for data validation were implemented. We show here how data on the frequency of occurrence from birdwatching lists can be analysed to estimate the timing and duration of the migration period. Aerial insectivores showed clear species-specific arrival patterns, with sand martins arriving first, followed in succession by swallows, house martins and finally swifts. Wheatears showed two peaks of arrivals, one for the British population and one for passage migrants from Greenland. The progression of arrivals from south to north and variation in arrival timing between years were also demonstrated. The method offers considerable potential for studying migration phenology at large spatial scales, and within Britain and Ireland it is now being applied throughout the year within the BTO/RSPB/BWI BirdTrack project. It could potentially be implemented at a continental scale, at which it would provide an important tool for measuring the growing impacts of global climate change on bird populations.
Above- and belowground net primary production in a temperate mixed deciduous forest
Newman, GS Arthur, MA Muller, RN
ECOSYSTEMS 9:3 317-329
Our current ability to detect and predict changes in forest ecosystem productivity is constrained by several limitations. These include a poor understanding of belowground productivity, the short duration of most analyses, and a need for greater examination of species- or community-specific variability in productivity studies. We quantified aboveground net primary productivity (ANPP) over 3 years (1999-2001), and both belowground NPP (BNPP) and total NPP over 2 years (2000-2001) in both mesic and xeric site community types of the mixed mesophytic forest of southeastern Kentucky to examine landscape variability in productivity and its relation with soil resource [water and nitrogen (N)] availability. Across sites, ANPP was significantly correlated with N availability (R-2 = 0.58, P = 0.028) while BNPP was best predicted by soil moisture content (R-2 = 0.72, P = 0.008). Because of these offsetting patterns, total NPP was unrelated to either soil resource. Interannual variability in growing season precipitation during the study resulted in a 50% decline in mesic site litter production, possibly due to a lag effect following a moderate drought year in 1999. As a result, ANPP in mesic sites declined 27% in 2000 compared to 1999, while xeric sites had no aboveground production differences related to precipitation variability. If global climate change produces more frequent occurrences of drought, then the response of mesic sites to prolonged moisture deficiency and the consequences of shifting carbon (C) allocation on C storage will become important questions.
A comparative analysis of woody biomass and coal for electricity generation under various CO2 emission reductions and taxes
Gan, JB Smith, CT
BIOMASS & BIOENERGY 30:4 296-303
Mitigating global climate change via CO2 emission control and taxation is likely to enhance the economic potential of bioenergy production and utilization. This study investigated the cost competitiveness of woody biomass for electricity production in the US under alternative CO2 emission reductions and taxes. We first simulated changes in the price of coal for electricity production due to CO2 emission reductions and taxation using a computable general equilibrium model. Then, the costs of electricity generation fueled by energy crops (hybrid poplar), logging residues, and coal were estimated using the capital budgeting method. Our results indicate that logging residues would be competitive with coal if emissions were taxed at about US$25 Mg-1 CO2, while an emission tax US$100Mg(-1) CO2 or higher would be needed for hybrid poplar plantations at a yield of 11.21 dry Mg ha(-1)yr(-1) (5 dry tons ac(-1)yr(-1)) to compete with coal in electricity production. Reaching the CO2 emission targets committed under the Kyoto Protocol would only slightly increase the price of fossil fuels, generating little impact on the competitiveness of woody biomass. However, the price of coal used for electricity production would significantly increase if global CO2 emissions were curtailed by 20% or more. Logging residues would become a competitive fuel source for electricity production if current global CO2 emissions were cut by 20-30%. Hybrid poplar plantations would not be able to compete with coal until emissions were reduced by 40% or more. (c) 2005 Elsevier Ltd. All rights reserved.
Marine lake ecosystem dynamics illustrate ENSO variation in the tropical western Pacific
Martin, LE Dawson, MN Bell, LJ Colin, PL
BIOLOGY LETTERS 2:1 144-147
Understanding El Nino/Southern Oscillation (ENSO) and its biological consequences is hindered by a lack of high-resolution, long-term data from the tropical western Pacific. We describe a preliminary, 6 year dataset that shows tightly coupled ENSO-related bio-physical dynamics in a seawater lake in Palau, Micronesia. The lake is more strongly stratified during La Nina than El Nino conditions, temperature anomalies in the lake co-vary strongly with the Nino 3.4 climate index, and the abundance of the dominant member of the pelagic community, an endemic subspecies of zooxanthellate jellyfish, is temperature associated. These results have broad relevance because the lake: (i) illustrates an ENSO signal that is partly obscured in surrounding semi-enclosed lagoon waters and, therefore, (ii) may provide a model system for studying the effects of climate change on community evolution and cnidarian-zooxanthellae symbioses, which (iii) should be traceable throughout the Holocene because the lake harbours a high quality sediment record; the sediment record should (iv) provide a sensitive and regionally unique record of Holocene climate relevant to predicting ENSO responses to future global climate change and, finally, (v) seawater lake ecosystems elsewhere in the Pacific may hold similar potential for past, present, and predictive measurements of climate variation and ecosystem response.
Can the invaded range of a species be predicted sufficiently using only native-range data? Lehmann lovegrass (Eragrostis lehmanniana) in the southwestern United States
Mau-Crimmins, TM Schussman, HR Geiger, EL
ECOLOGICAL MODELLING 193:3-4 736-746
Predictions of species invasions are often made using information from their native ranges. Acquisition of native-range information can be very costly and time-consuming and in some cases may not reflect conditions in the invaded range. Using information from the invaded range can enable much faster modeling at finer geographic resolutions than using information from a species’ native range. We used confirmed presence points from the native range, southern Africa, and the invaded range, the southwestern United States, to predict the potential distribution of the perennial bunchgrass Eragrostis lehmanniana Nees, (Lehmann lovegrass), in its invaded range in the United States. The two models showed strong agreement for the area encompassed by the presence points in the invaded range, and offered insight into the overlapping but slightly different ecological niche occupied by the introduced grass in the invaded range. Regions outside of the scope of inference showed less agreement between the two models. E. lehmanniana was selected via seeding trials before being planted in the United States and therefore represents an isolated genotype from the native-range population. Models built using confirmed presence points from the invaded range can provide insight into how the selected genotype is expressed on the landscape and considers influences not present in the native range. Models created from locations in both the invaded and native ranges can lead to a more complete understanding of an introduced species’ potential for spread, especially in the case of anthropogenic selection. (C) 2005 Elsevier B.V. All rights reserved.
Paleomonsoon precipitation deduced from a sediment core from the equatorial Indian Ocean
Tiwari, M Ramesh, R Somayajulu, BLK Jull, AJT Burr, GS
GEO-MARINE LETTERS 26:1 23-30
Rapid shifts in past climate recorded in polar ice sheets have elicited various explanations relating to either thermohaline circulation changes by ice-rafting or natural greenhouse gas concentrations modulated by climatic conditions in the tropics. To compare the tropical paleoclimate record with the polar record, one must choose sediment cores from highly productive ocean regions. Necessarily, such regions reflect the wind records in the tropics, because high productivity is associated with upwelling driven by winds. Comparing tropical precipitation records with high-latitude records is, however, a more difficult task because sediments recording paleoprecipitation usually have low sedimentation rates, and offer coarser resolution relative to polar ice cores. Here, we present delta O-18 data of three planktonic species of Foraminifera (a proxy for precipitation) from such a sediment core, spanning the past 35 ka for the equatorial Indian Ocean, which falls under the southwest monsoon (SWM) realm. Results show that minimum SWM precipitation occurred at the Last Glacial Maximum, with a subsequent increase at Termination IA. During the Holocene, SWM precipitation intensified uniformly up to the core top (similar to 2.2 ka B.P.), as revealed by generally decreasing delta O-18 values. Variations in precipitation are consistent with climate changes recorded in polar ice sheets. Although the different resolutions of the two records preclude a rigorous comparison, abrupt cooling/warming events appear to be accompanied by sudden reduction/enhancement in (SWM) rainfall. Thus, mechanisms with time scales much shorter than a millennium, such as natural greenhouse warming (e.g., CH4 concentration), controlled by emissions from the tropics, could have played a major role in high-latitude climate change.
The (OECTS)-E-bj framework for integrated assessment: Hybrid modeling of transportation
Kim, SH Edmonds, J Lurz, J Smith, SJ Wise, M
ENERGY JOURNAL : 63-91
Technology is a central issue for the global climate change problem, requiring analysis tools that can examine the impact of specific technologies within a long-term, global context. This paper describes the architecture of the ObjECTS-MiniCAM integrated assessment model, which implements a long-term, global model of energy, economy, agriculture, land-use, atmosphere, and climate change in a framework that allows the flexible incorporation of explicit technology detail. We describe the implementation of a “bottom-up” representation of the transportation sector as an illustration of this approach, in which the resulting hybrid model is fully integrated, internally consistent and theoretically compatible with the regional and global modeling framework. The analysis of the transportation sector presented here supports and clarifies the need for a comprehensive strategy promoting advanced vehicle technologies and. an economy-wide carbon policy to cost-effectively reduce carbon emissions from the transportation sector in the long-term.
Phenotypic diversity amongst strains of Pleurotus sajor-caju: implications for cultivation in and environments
Kashangura, C Hallsworth, JE Mswaka, AY
MYCOLOGICAL RESEARCH 110: 312-317
In and regions, biodiversity and biomass are limited by water availability, and this problem has been compounded by desertification associated with global climate change. The saprotrophic macrofungi that are indigenous to hot subtropical and tropical regions, such as Pleurotus spp., can play key roles in water sequestration, nutrient cycling, human nutrition, and bioremediation of waste materials. We studied 15 strains of Pleurotus sajor-caju, a widespread and phenotypically-diverse species, to establish variability in growth response and primordium development over a range of stress parameters: osmotic potential (-0.5 to -5 MPa), temperature (5-40 degrees C) and pH (2-12). The initiation of primordia precedes basidiome production and therefore represents a key stage in bioremediation strategies and fungi-driven nutrient cycles. Primordia. were produced at low pH (4-6), at suboptimal growth temperatures (<= 25 degrees C), and under moderate water stress (-0.5 to -3.5 MPa). Although the growth windows for different strains were similar, their maximum growth rates and the optimum conditions for growth varied. We discuss the phenotypic diversity of Pleurotus strains and discuss their potential for cultivation, bioremediation and ecological regeneration. (c) 2005 The British Mycological Society. Published by Elsevier Ltd. All rights reserved.
Root exudation (net efflux of amino acids) may increase rhizodeposition under elevated CO2
Philips, DA Fox, TC Six, J
GLOBAL CHANGE BIOLOGY 12:3 561-567
Increases in atmospheric CO2 concentration ([CO2]) can lead to global climate change and theoretically could enhance carbon (C) deposition in soil, but data on this complex issue are contradictory. One approach for clarifying the diverse forces influencing plant-derived C in the rhizosphere involves defining how elevated [CO2] alters the fundamental process of C transfer from plant roots to the soil. We examine here how a step increase in [CO2] affects the innate influx and efflux components of root exudation in axenic plants, as one foundation for understanding how climate change may affect rhizodeposition. Increasing [CO2] from 425 to 850 mu mol mol(-1) during short-term trials enhanced shoot and root dry weight (P < 0.01) of annual rye grass (Lolium multiflorum Lam.) and medic (Medicago truncatula L.) but had no effect on growth of maize (Zea mays L.). Root amino-acid flux in the same plants changed only in maize, which increased the efflux rate (nmol g root fresh weight(-1) h(-1)) of six amino acids (arginine, alanine, proline, tyrosine, lysine and leucine) significantly (P < 0.05) under elevated [CO2]. None of the three plant species altered the steady-state concentration of 16 amino acids released into a hydroponic solution with changing [CO2], apparently because amino-acid influx rates, measured at 2.5 mu M, consistently exceeded efflux rates. Indeed, plants recovered amino acids at rates 94-374% higher than they were lost from roots regardless of [CO2]. These results indicate that, in theory, any effect of [CO2] doubling on amino-acid efflux can be offset by innately higher rates of influx. In practice, however, higher rates of amino-acid cycling (i.e., efflux+influx) for each root segment (in C-4 maize) or from more root tissue (in the two C-3 species) should increase root exudation by plants exposed to elevated [CO2] as additional amino acids would be adsorbed to soil particles or be taken up by soil microorganisms.
GFDL’s CM2 global coupled climate models. Part I: Formulation and simulation characteristics
Delworth, TL Broccoli, AJ Rosati, A Stouffer, RJ Balaji, V Beesley, JA Cooke, WF Dixon, KW Dunne, J Dunne, KA Durachta, JW Findell, KL Ginoux, P Gnanadesikan, A Gordon, CT Griffies, SM Gudgel, R Harrison, MJ Held, IM Hemler, RS Horowitz, LW Klein, SA Knutson, TR Kushner, PJ Langenhorst, AR Lee, HC Lin, SJ Lu, J Malyshev, SL Milly, PCD Ramaswamy, V Russell, J Schwarzkopf, MD Shevliakova, E Sirutis, JJ Spelman, MJ Stern, WF Winton, M Wittenberg, AT Wyman, B Zeng, F Zhang, R
JOURNAL OF CLIMATE 19:5 643-674
The formulation and simulation characteristics of two new global coupled climate models developed at NOAA’s Geophysical Fluid Dynamics Laboratory (GFDL) are described. The models were designed to simulate atmospheric and oceanic climate and variability from the diurnal time scale through multicentury climate change, given our computational constraints. In particular, an important goal was to use the same model for both experimental seasonal to interannual forecasting and the study of multicentury global climate change, and this goal has been achieved. Two versions of the coupled model are described, called CM2.0 and CM2.1. The versions differ primarily in the dynamical core used in the atmospheric component, along with the cloud tuning and some details of the land and ocean components. For both coupled models, the resolution of the land and atmospheric components is 2 degrees latitude x 2.5 degrees longitude, the atmospheric model has 24 vertical levels. The ocean resolution is 1 degrees in latitude and longitude, with meridional resolution equatorward of 30 degrees becoming progressively finer, such that the meridional resolution is 1/3 degrees at the equator. There are 50 vertical levels in the ocean, with 22 evenly spaced levels within the top 220 m. The ocean component has poles over North America and Eurasia to avoid polar filtering. Neither coupled model employs flux adjustments. The control simulations have stable, realistic climates when integrated over multiple centuries. Both models have simulations of ENSO that are substantially improved relative to previous GFDL coupled models. The CM2.0 model has been further evaluated as an ENSO forecast model and has good skill (CM2.1 has not been evaluated as an ENSO forecast model). Generally reduced temperature and salinity biases exist in CM2.1 relative to CM2.0. These reductions are associated with 1) improved simulations of surface wind stress in CM2.1 and associated changes in oceanic gyre circulations; 2) changes in cloud tuning and the land model, both of which act to increase the net surface shortwave radiation in CM2.1, thereby reducing an overall cold bias present in CM2.0; and 3) a reduction of ocean lateral viscosity in the extratropics in CM2.1, which reduces sea ice biases in the North Atlantic. Both models have been used to conduct a suite of climate change simulations for the 2007 Intergovernmental Panel on Climate Change (IPCC) assessment report and are able to simulate the main features of the observed warming of the twentieth century. The climate sensitivities of the CM2.0 and CM2.1. models are 2.9 and 3.4 K, respectively. These sensitivities are defined by coupling the atmospheric components of CM2.0 and CM2.1 to a slab ocean model and allowing the model to come into equilibrium with a doubling of atmospheric CO2. The output from a suite of integrations conducted with these models is freely available online (see http://nomads.gfdl.noaa.gov/).
Climate change and the future of shipping and ship design
NAVAL ENGINEERS JOURNAL 118:3 151-163
In 2001, the Intergovernmental Panel on Climate Change (IPCC) issued a series of alarming reports that outlined the likely consequences of climate change over the next 50 to 100 years. Subsequent to those reports, in early 2005, the Kyoto Protocol took effect, establishing modest targets for reducing emissions of global-warming gases by certain countries. Those targets are widely considered to be inadequate to do the job. >> In 2007, the IPCC will issue its next series of reports, and it is widely anticipated that those reports will paint a grim picture of the future, possibly setting off another round of calls to action and negotiations for tougher treaty requirements.))Whatever the immediate reaction to the 2007 IPCC reports, determined action by developed and developing nations alike appears inevitable. That determined action will affect every economic sector, including the shipping and shipbuilding industries. >> So it’s coming time for the leaders, owners, operators, technologists, designers, and manufacturers in the U.S. domestic shipping and shipbuilding industries to begin contemplating what actions they will take to address possible legal requirements associated with global climate change. >> Previous papers on climate change by this author have focused on ship technologies (Breslin & Wang, 2004) as well as DoN acquisition strategies (Breslin, 2003). The purpose of this paper is to outline where we are and where we are likely to be going relative to treaties and domestic legislation associated with climate change, speculate on the likely implications relative to shipping and shipbuilding, and outline a rough path into the future.
Temperature-dependent effects of cadmium on mitochondrial and whole-organism bioenergetics of oysters (Crassostrea virginica)
Lannig, G Cherkasov, AS Sokolova, IM
MARINE ENVIRONMENTAL RESEARCH 62: Suppl. S S79-S82
Intertidal mollusks are exposed to multiple stressors in estuaries, including temperature and trace metals such as cadmium, which may interactively affect their physiology. We have studied the combined effects of temperature and cadmium stress on metabolism of oysters at the whole animal and mitochondrial levels. In vivo exposure to 50 mu g L-1 Cd led to a significant increase in basal metabolic rate (BMR) in 20 degrees C-acclimated but not in 28 degrees C-acclimated oysters. Cadmium exposure resulted in a fast decrease in mitochondrial capacity to synthesize ATP in 28 degrees C-acclimated but not 20 degrees C-acclimated oysters indicating that mitochondria, may be functioning closer to their capacity limits in the former group. This agrees with elevated mortality in Cd-exposed oysters at 28 degrees C but not 20 degrees C. In general, elevated temperature increased sensitivity of oysters to cadmium at mitochondrial and whole-organism levels suggesting that oyster populations may become more susceptible to trace metal pollution during seasonal warming and/or global climate change. (c) 2006 Elsevier Ltd. All rights reserved.
Dust storm in Asia continent and its bio-environmental effects in the North Pacific: A case study of the strongest dust event in April, 2001 in central Asia
Han, YX Fang, XM Xi, XX Song, LC Yang, SL
CHINESE SCIENCE BULLETIN 51:6 723-730
Testing the effects of iron fertilization in booming metabolism of microbes in North Pacific Ocean has become an important hot topic in current global climate change study. The first supportive evidence with natural iron inputs to ocean was obtained by Bishop and his colleagues at the PAPA region in North Pacific Ocean. They found a rapid increase of marine phytoplankton over North Pacific Ocean after a strong dust storm in April 2001. We demonstrate that the dust deposition flux during this dust storm period decreases exponentially with increasing distance from the dust source regions along the dust transport pathway, through integration of synoptic dynamics, changes of TOMS-Al (aerosol index) and surface PM10 values along the dust pathway and changes of particulate organic carbon and chlorophyll in surface oceans. This strong dust storm may result in deposition of about 3.1-5.8 mu g/m(3) eolian iron into the PAPA region in North Pacific Ocean, thus causing a rapid increase of marine phytoplankton productivity observed by Bishop and his colleagues. This work supplies more direct and detailed evidence, from continental dust process, to support the iron hypothesis with natural iron inputs to the surface oceans through dust storms.
Uncertainties of climate change in arid environments of Central Asia
Lioubimtseva, E Cole, R
REVIEWS IN FISHERIES SCIENCE 14:1-2 29-49
This article examines the key uncertainties of climate change in the Central Asian republics of the former USSR-a vast arid region arid a classic example of complex and poorly understood interactions between the regional responses to global climate change and the local human-induced desertification. Based on paleoanalogous scenarios, Central Asian deserts are often predicted to become wetter as a result of global warming because they are located north of 30 degrees latitude. However despite some similarities between the paleoclimate changes and greenhouse warming, such predictions have very serious limitations. Climate models predict that the temperature in and Central Asia will increase by 1-2 degrees C by 2030-2050, with the greatest increases in wintertime. Some models project greater aridity in the future though others project less aridity, and it is becoming increasingly apparent that climate change modeling in arid zones is extremely uncertain because of the extreme natural variability (both temporal and spatial) of the desert climate. The physical differences of climate change forcings imply that one might expect quite different regional responses to future human-induced climate change compared to the Holocene climate in terms of their rapidity and amplitude. Local and regional human impacts, such as massive irrigation, may have a stronger impact on the climatic system at the regional level than global climate change.
Flexible multi-gas climate policies
ENERGY JOURNAL : 163-175
I analyse the costs of policies aimed at stabilising global climate change. I show that abatement of all major greenhouse gases is important to the costs of climate policies and that flexible reduction of methane and other non-CO2 gases may reduce costs significantly. The non-CO2 gases offer many low-cost abatement options and this reduces the need for abatement of CO2 to stabilise climate change. Multi-gas flexibility may be important if climate policies reflect not only long-term stabilisation, but also the rate at which the climate changes, as the latter may require large reductions in emissions in the short-term.
Application of Landsat-7 satellite data and a DEM for the quantification of thermokarst-affected terrain types in the periglacial Lena-Anabar coastal lowland
Grosse, G Schirrmeister, L Malthus, TJ
POLAR RESEARCH 25:1 51-67
Extensive parts of Arctic permafrost-dominated lowlands were affected by large-scale permafrost degradation, mainly through Holocene thermokarst activity. The effect of thermokarst is nowadays observed in most periglacial lowlands of the Arctic. Since permafrost degradation is a consequence as well as a significant factor of global climate change, it is necessary to develop efficient methods for the quantification of its past and current magnitude. We developed a procedure for the quantification of periglacial lowland terrain types with a focus on degradation features and applied it to the Cape Mamontov Klyk area in the western Laptev Sea region. Our terrain classification approach was based on a combination of geospatial datasets, including a supervised maximum likelihood classification applied to Landsat-7 ETM+ data and digital elevation data. Thirteen final terrain surface classes were extracted and subsequently characterized in terms of relevance to thermokarst and degradation of ice-rich deposits. 78% of the investigated area was estimated to be affected by permafrost degradation. The overall classification accuracy was 79%. Thermokarst did not develop evenly on the coastal plain, as indicated by the increasingly dense coverage of thermokarst-related areas from south to north. This regionally focused procedure can be extended to other areas to provide the highly detailed periglacial terrain mapping capabilities currently lacking in global-scale permafrost datasets.
Spatial distribution of rainfall trends in Sicily (1921-2000)
Cannarozzo, M Noto, LV Viola, F
PHYSICS AND CHEMISTRY OF THE EARTH 31:18 1201-1211
The feared global climate change could have important effects on various environmental variables including rainfall in many countries around the world. Changes in precipitation regime directly affect water resources management, agriculture, hydrology and ecosystems. For this reason it is important to investigate the changes in the spatial and temporal rainfall pattern in order to improve water management strategies. In this study a non-parametric statistical method (Mann-Kendall rank correlation method) is employed in order to verify the existence of trend in annual, seasonal and monthly rainfall and the distribution of the rainfall during the year. This test is applied to about 250 rain gauge stations in Sicily (Italy) after a series of procedures finalized to the estimation of missing records and to the verification of data consistency. In order to understand the regional pattern of precipitation in Sicily, the detected trends are spatially interpolated using spatial analysis techniques in a GIS environment. The results show the existence of a generalized negative trend for the entire region. (c) 2006 Elsevier Ltd. All rights reserved.
Reducing conflicts between climate policy and energy policy in the US: The important role of the states
Peterson, TD Rose, AZ
ENERGY POLICY 34:5 619-631
The absence of US national action oil global climate change policy has prompted initiatives by the US Congress, cities, states, and regions toward what is likely to become it long-term, collaborative effort to harmonize national energy and climate policies. This upward evolution in the face of it reluctant administration is historically consistent with the development of national legislation on other environmental and social issues in the US. At the heart of this movement is the need to resolve conflicts between high-intensity use of low-cost fossil energy Supplies, and the dominating impact of carbon dioxide emissions oil global climate change. US states are among the largest carbon dioxide emitters in the world and play a critical role in supplying and transforming energy, its well as consuming it, for economic advantage. State governments are also likely to have to shoulder some of the cost of potentially extensive climate damages and bear the brunt of the cost of implementing future federal mandates. As a result, many are taking proactive stances oil the development of climate mitigation policy to prepare for, accelerate, and/or guide national policy. As US states show leadership on addressing greenhouse gas emissions, they also play an important role in forging policies and measures that reduce economic conflict between energy and climate goals. A number have launched or completed greenhouse gas mitigation plans and other major policies in the past few years that address these conflicts through: (1) finding ways to reduce mitigation costs, including the use of incentive-based policy instruments; (2) promoting ail open and democratic policy process that includes major stakeholders; (3) promoting equity across socioeconomic groups, regions, and generations; and (4) promoting interregional cooperation. The results are promising and suggest that the state arena for climate and energy policy is evolving quickly and constructively toward alternatives that reduce conflict. Regional efforts are also unfolding, along with greater congressional attention to the lessons learned and commitments made by sub-federal actions. In the next few years many national energy and climate conflicts are likely to be tested and addressed by states. Among these, Pennsylvania is likely to be an important player due to its high profile of energy production and potential for leadership. (c) 2005 Elsevier Ltd. All rights reserved.
Soil organic carbon changes in diversified rotations of the western corn belt
SOIL SCIENCE SOCIETY OF AMERICA JOURNAL 70:2 426-433
dSequestration and storage of carbon (C) by agricultural soils has been cited as one potential part of the solution to soil degradation and global climate change. However, C sequestration in soils is a slow and dynamic process. The objective of this study was to evaluate the effects of crop rotation and N fertilizer management on soil organic C (SOC) levels at several points in time during 18 yr of a long-term study in the Western Corn Belt. Seven cropping systems (three monoculture, two 2-yr, and two 4-yr rotations) with three levels of N fertilizer were compared. Soil samples were taken in the spring in 1984, 1992, 1998, and 2002 to a depth of 30 cm in 0- to 7.5-, 7.5- to 15-, and 15- to 30-cm increments. No differences were obtained in SOC levels in 1984 at the beginning of the study. After 8 yr, rotation significantly increased SOC 449 kg ha(-1) across all cropping systems. From 1992 to 2002, SOC levels in the 0- to 7.5-cm depth decreased by 516 kg ha(-1) across all cropping systems. Soil organic C levels in the 7.5- to 15-cm depths in 1992 and 2002 demonstrated similar rotation effects to those in the surface 0- to 7.5-cm, being not significantly affected from 1984 to 1992 but being significantly decreased from 1992 to 2002 (568 kg SOC ha(-1) across all cropping systems). Many of the SOC gains in the surface 30 cm measured during the first 8 yr of the study were lost during the next 10 yr in all but the 4-yr cropping systems after 18 yr. The loss of SOC in this latter period occurred when depth of tillage was increased by using a tandem disk with larger-diameter disks. These results demonstrate that more than one point-in-time measurement from long-term experiments is necessary to monitor SOC changes when several management variables, such as cropping system and N fertilizer, are being used. They also indicate that apparent small changes in cultural practices, such as in depth of tillage in this experiment, can significantly change SOC dynamics in the soil. Subtle changes in cultural practices (e.g., tillage depth) can have significant long-term results, but longterm experiments are required to quantify their impact under variable climatic conditions.
Global warming: Can existing reserves really preserve current levels of biological diversity?
Li, MH Krauchi, N Gao, SP
JOURNAL OF INTEGRATIVE PLANT BIOLOGY 48:3 255-259
Paleoecological evidence and paleoclimatic records indicate that there was a plant poleward migration in latitude and an upward shift in elevation with increased temperatures after the last glaciation. Recent studies have shown that global warming over the past 100 years has been having a noticeable effect on living systems. Current global warming is causing a poleward and upward shift in the range of many plants and animals. Climate change, in connection with other global changes, is threatening the survival of a wide range of plant and animal species. This raises the question: can existing reserves really preserve current levels of biological diversity in the long term given the present rapid pace of climate change? The present paper deals with this question in the context of the responses of plants and animals to global climate change, based on a literature review. Consequently, we recommend expanding reserves towards the poles and/or towards higher altitudes, to permit species to shift their ranges to keep pace with global warming.
The use of genetic algorithms and Bayesian classification to model species distributions
Termansen, M McClean, CJ Preston, CD
ECOLOGICAL MODELLING 192:3-4 410-424
This paper develops a method to model species’ spatial distributions from environmental variables. The method is based on a search for an optimal identification of environmental niches to match observed species presence/absence data. The identification is based on Bayesian classification and the optimisation is based on a Genetic Algorithm (GA). The algorithm is tested on an artificial “species” and is shown to perform well. We apply the approach to a random sample of 100 plant species native to the British Isles. This enables an identification of the environmental variables that are most important for capturing the species’ spatial distribution. We show that both climate and land use variables are important for modelling the spatial distribution patterns of the sampled species. (c) 2005 Elsevier B.V. All rights reserved.
1851-2004 annual heat budget of the continental landmasses
GEOPHYSICAL RESEARCH LETTERS 33:4 -
Changing climate is accompanied by changing energy in various climate system components including the continental landmasses. When the temperature at ground surface rises, more heat will be deposited to the rocks beneath the ground subsurface, whereas when ground surface temperature falls, certain amount of heat will escape from the ground into the atmosphere. Based on the land-only global meteorological record, I analyze the annual heat budget of the world continents except for Antarctica. I show that between the period from 1851 to 2000 a total of 10.4 ZJ (Zetta-Joules or 10(21) J) of thermal energy had been absorbed by Africa, Asia, Australia, Europe, North America, and South America landmasses. An additional 1.34 ZJ of heat has been stored beneath the ground surface of these continents over the first four years of the 21st century from 2001 to 2004. The recent global climate change has led to an intensified heating in the continental landmasses.
Nest-site selection of endangered cinereous vulture (Aegypius monachus) populations affected by anthropogenic disturbance: present and future conservation implications
Moran-Lopez, R Guzman, JMS Borrego, EC Sanchez, AV
ANIMAL CONSERVATION 9:1 29-37
The cinereous vulture Aegypius monachus is the largest bird of the western Palaearctic, and is threatened over its entire range of distribution. Considering explicitly the influence of human interference, we studied breeding habitat selection in seven breeding colonies using a geographic information system and multivariate statistical models. Steep areas far from human disturbance constituted the preferential breeding sites in all the colonies. The nesting substrate and climatic conditions varied between colonies, but always corresponded to non-extreme climates, and included tree species of adequate size. Since human activities influenced the breeding habitat choice, there is a potential for management policies that can clearly be of benefit for the conservation of this vulture. These would fundamentally be as follows: (1) forestry activity should be oriented to protecting oak (Quercus spp.) and pine (Pinus ssp.) stands, especially individual trees of great height, and to replacing eucalyptus (Eucalyptus spp.) with autochthonous species; (2) activities (recreational, economic, etc.) around the breeding areas should be scheduled and spatially organized to avoid disturbance, particularly those deriving from the proximity of roads and tracks; (3) the expected effects of global warming should be compensated, identifying future sites where the habitat can be managed, supplementary food can be provided and reserves can be designed.
The relationship between phytoplankton diversity and community function in a coastal lagoon
Duarte, P Macedo, MF da Fonseca, LC
HYDROBIOLOGIA 555: 3-18
The decrease of biodiversity related to the phenomena of global climate change is stimulating the scientific community towards a better understanding of the relationships between biodiversity and ecosystem functioning. In ecosystems where marked biodiversity changes occur at seasonal time scales, it is easier to relate them with ecosystem functioning. The objective of this work is to analyse the relationship between phytoplankton diversity and primary production in St. Andre coastal lagoon - SW Portugal. This lagoon is artificially opened to the sea every year in early spring, exhibiting a shift from a marine dominated to a low salinity ecosystem in winter. Data on salinity, temperature, nutrients, phytoplankton species composition, chlorophyll a (Chl a) concentration and primary production were analysed over a year. Modelling studies based on production-irradiance curves were also conducted. A total of 19 taxa were identified among diatoms, dinoflagellates and euglenophyceans, the less abundant group. Lowest diversities (Shannon-Wiener index) were observed just before the opening to the sea. Results show a negative correlation (p < 0.05) between diversity and chlorophyll a (Chl a) concentration (0.2-40.3 mg Chl a m(-3)). Higher Chl a values corresponded to periods when the community was dominated by the dinoflagellate Prorocentrum minimum (> 90% of cell abundance) and production was maximal (up to 234.8 mg C m(-3) h(-1)). Maximal photosynthetic rates (P-max) (2.0-22.5 mg C mg Chl a(-1) h(-1)) were higher under lower Chl a concentrations. The results of this work suggest that decreases in diversity are associated with increases in biomass and production, whereas increases correspond to opposite trends. It is suggested that these trends, contrary to those observed in terrestrial and in some benthic ecosystems, may be a result of low habitat diversity in the water column and resulting competitive pressure. The occurrence of the highest photosynthetic rates when Chl a is low, under some of the highest diversities, suggests a more efficient use of irradiance under low biomass-high diversity conditions. Results suggest that this increased efficiency is not explained by potential reductions in nutrient limitation and intraspecific competition under lower biomasses and may be a result of niche complementarity.
Phosphorus geochemistry in the Luochuan loess section, North China and its paleoclimatic implications
Rao, WB Chen, J Luo, TY Liu, LW
QUATERNARY INTERNATIONAL 144: 72-83
Total P (P-t) on a carbonate-free basis in an entire loess-paleosol sequence and P-t, organic P (P-o) and inorganic P (P-i) in the S-0-L-1-S-1 sequence were investigated in detail with different resolutions for the Luochuan loess section from northern China. P-t content varies between 393 and 786 ppm throughout the loess-paleosol sequence, and is generally higher in the loess than in interstratified paleosols, showing fluctuation cycles of 100ka in correspondence to loess-paleosol alternations. P-t variations on a carbonate-free basis in the loess-paleosol sequence could indicate variations in atmosphere precipitation resulting in different leaching loss of P from palcosols. P-i has an average value of 499 ppm with a range of 324-560 ppm, accounting for more than 70% of P-t in the S-0-L-1-S-1 sequence, where the minimum of P-i in the Malan loess is higher than the maximum of P-i in S-1. P-o ranges between 59 and 233 ppm with an average of 132 ppm in the S-0-L-1-S-1 sequence. Phosphorus (P) was initially delivered to the Luochuan loess section via influx of aeolian dust from the northern desert and Gobi areas by the East Asian winter monsoon, and then was modified by pedogenesis associated with the East Asian summer monsoon during the last 130 ka. ” Preserved P-t” in the loess L-1 is tightly correlated with grain size without leaching loss of P due to enrichment of P in fine-grained fractions, as well as ” initial P-t”. ” Leaching P-t” data show that paleosol S-1 had lost 15-40% of its ” initial P-t”, and that there was much more precipitation in S-1 than in L-1. P-i subject to slightly weak pedogenesis was completely transformed into P-o without leaching loss of P in loess L-1. By contrast, much P-i disappeared from paleosol S, due to strong pedogenesis, partly through leaching and partly through conversion to organic forms during P cycling processes. P-o variation is similar to those of MS and the < 7.8 mu m fraction in L-1, but contains more information on the East Asian winter monsoon due to weak pedogenesis without leaching of P. P-o in S-1 lower than L1SS1, as a consequence of strong decomposition of the organic matter kept constantly in the middle of S-1 where P-i kept at the lowest of 423 ppm, suggesting that there existed a very warm and humid climate related to the enhanced summer monsoon during that period. The mean organic P/inorganic P ratio (P-o/P-i) is lower in the L1LL1 and L1LL2 than in the S-0, S-1, and L1SS1, indicating that low P-o/P-i ratios coincide with weak weathering-pedogenesis, and higher P-o/P-i ratios correspond to strong weathering-pedogenesis. P-o/P-i ratio can eliminate the effect of grain size on aeolian dust because of chemical uniformity of aeolian dust and enrichment of P-o and P-i in the fine-grained fractions. Thus, P-o/P-i ratio is solely linked to pedogenesis of the Luochuan loess section. Variation in P-o/P-i ratiois similar to those of MS and the Marine Oxygen Isotope composition, indicating the summer monsoon evolution during the last 130 ka and providing the biogeochemical evidence for further understanding the genetic links between the East Asian monsoon and global climate change. (c) 2005 Elsevier Ltd and INQUA. All rights reserved.
Quantifying relationships between bird and butterfly community shifts and environmental change
Debinski, DM VanNimwegen, RE Jakubauskas, ME
ECOLOGICAL APPLICATIONS 16:1 380-393
Quantifying the manner in which ecological communities respond during a time of decreasing precipitation is a first step in understanding how they will respond to longer-term climate change. Here we coupled analysis of interannual variability in remotely sensed data with analyses of bird and butterfly community changes in montane meadow communities of the Greater Yellowstone Ecosystem. Landsat satellite imagery was used to classify these meadows into six types along a hydrological gradient. The northern portion of the ecosystem, or Gallatin region, has smaller mean patch sizes separated by ridges of mountains, whereas the southern portion of the ecosystem, or Teton region, has much larger patches within the Jackson Hole valley. Both support a similar suite of butterfly and bird species. The Gallatin region showed more overall among-year variation in the normalized difference vegetation index (NDVI) when meadow types were pooled within regions, perhaps because the patch sizes are smaller on average. Bird and butterfly communities showed significant relationships relative to meadow type and NDVI. We identified several key species that are tightly associated with specific meadow types along the hydrological gradient. Comparing taxonomic groups, fewer birds showed specific habitat affinities than butterflies, perhaps because birds are responding to differences in habitat structure among meadow types and using the landscape at a coarser scale than the butterflies. Comparing regions, the Teton region showed higher predictability of community assemblages as compared to the Gallatin region. The Gallatin region exhibited more significant temporal trends with respect to butterflies. Butterfly communities in wet meadows showed a distinctive shift along the hydrological gradient during a drought period (1997-2000). These results imply that the larger Teton meadows will show more predictable (i.e., static) species-habitat associations over the long term, but that the smaller Gallatin meadows may be an area that will exhibit the effects of global climate change faster.
Niche breadth, competitive strength and range size of tree species: a trade-off based framework to understand species distribution
Morin, X Chuine, I
ECOLOGY LETTERS 9:2 185-195
Understanding the mechanisms causing latitudinal gradients in species richness and species range size is a central issue in ecology, particularly in the current context of global climate change. Different hypotheses have been put forward to explain these patterns, emphasizing climatic variability, energy availability and competition. Here we show, using a comparative analysis controlling for phylogeny on 234 temperate/boreal tree species, that these hypotheses can be included into a single framework in an attempt to explain latitudinal gradients in species range size. We find that species tend to have larger ranges when (i) closer to the poles, (ii) successionally seral, (iii) having small and light seeds, and (iv) having short generations. The patterns can simply be explained by energy constraints associated with different life-history strategies. Overall, these findings shed a new light on our understanding of species distribution and biodiversity patterns, bringing new insights into underlying large-scale evolutionary processes.
Wind generation, power system operation, and emissions reduction
Denny, E O’Malley, M
IEEE TRANSACTIONS ON POWER SYSTEMS 21:1 341-347
With increasing concern over global climate change, policy makers are promoting renewable energy sources, predominantly wind generation, as a means of meeting emissions reduction targets. Although wind generation does not itself produce any harmful emissions, its effect on power system operation can actually cause an increase in the emissions of conventional plants. A dispatch model was developed that analyzes the impact that wind generation has on the operation of conventional plants and the resulting emissions of carbon dioxide (CO2), sulphur dioxide (SO2), and oxides of nitrogen (NOX). The analysis concentrates on a “forecasted” approach that incorporates wind generation forecasts in the dispatch decisions. It was found that wind generation could be used as a tool for reducing CO2 emissions but alone, it was not effective in curbing SO2 and NOX emissions.
Top-down herbivory and bottom-up El Nino effects on Galapagos rocky-shore communities
Vinueza, LR Branch, GM Branch, ML Bustamante, RH
ECOLOGICAL MONOGRAPHS 76:1 111-131
We evaluated the effects of marine iguanas, sally lightfoot crabs, and fish on rocky-shore sessile organisms at two sites at Santa Cruz Island, Galapagos Islands, Ecuador, for 3-5 years during and after the 1997-1998 El Nino, using exclusion cages to separate the effects. Plots exposed to natural grazing were dominated either by encrusting algae or by red algal turf and articulated corallines. Algae fluctuated in response to El Nino in the following way. During an early phase, crustose Gymnogongrus and/or red algal turf were dominant. In the heart of El Nino, grazers had limited effects on algal cover but influenced algal sizes substantially. Most algae (particularly edible forms) were scarce or declined, although warm-water ephemeral species (notably Giffordia mitchelliae) flourished, increasing diversity and overgrowing crusts. Iguana mortalities were high, and crab densities low. When normal conditions returned, warm-water ephemerals declined, crab densities rose, and grazers had significant but site-specific effects on algae. At one site, any combination of grazers diminished most erect species, reducing diversity and restoring dominance of competitively inferior grazer-resistant crusts. At a second site, only the combined effect of all grazers had this effect. Laboratory experiments confirmed that crabs could control erect algae and promote crustose forms, and crustose Gymnogongrus developed into an erect form in the absence of crabs. Differences between sites and large-scale temporal changes associated with El Nino indicate that tropical shores are not all as constant in time and space as previously suggested. Mobile grazers did affect algal communities, but over the period of our observations far greater effects were attributable to intersite differences and temporal shifts in oceanographic conditions. El Nino events reduce nutrients, intensify wave action, and raise sea levels, affecting food availability for intertidal herbivores and their influence on benthic algae. Thus, the dramatic transformations of communities during El Nino presage the impacts of global climate change.
Rainfall and its seasonality over the Amazon in the 21st century as assessed by the coupled models for the IPCC AR4
Li, WH Fu, R Dickinson, RE
JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES 111:D2 -
 The global climate models for the Intergovernmental Panel on Climate Change Fourth Assessment Report (IPCC AR4) predict very different changes of rainfall over the Amazon under the SRES A1B scenario for global climate change. Five of the eleven models predict an increase of annual rainfall, three models predict a decrease of rainfall, and the other three models predict no significant changes in the Amazon rainfall. We have further examined two models. The UKMO-HadCM3 model predicts an El Nino-like sea surface temperature (SST) change and warming in the northern tropical Atlantic which appear to enhance atmospheric subsidence and consequently reduce clouds over the Amazon. The resultant increase of surface solar absorption causes a stronger surface sensible heat flux and thus reduces relative humidity of the surface air. These changes decrease the rate and length of wet season rainfall and surface latent heat flux. This decreased wet season rainfall leads to drier soil during the subsequent dry season, which in turn can delay the transition from the dry to wet season. GISS-ER predicts a weaker SST warming in the western Pacific and the southern tropical Atlantic which increases moisture transport and hence rainfall in the Amazon. In the southern Amazon and Nordeste where the strongest rainfall increase occurs, the resultant higher soil moisture supports a higher surface latent heat flux during the dry and transition season and leads to an earlier wet season onset.
Consequences of simultaneous elevation of carbon dioxide and temperature for plant-herbivore interactions: a metaanalysis
Zvereva, EL Kozlov, MV
GLOBAL CHANGE BIOLOGY 12:1 27-41
The effects of elevated carbon dioxide on plant-herbivore interactions have been summarized in a number of narrative reviews and metaanalyses, while accompanying elevation of temperature has not received sufficient attention. The goal of our study is to search, by means of metaanalysis, for a general pattern in responses of herbivores, and plant characteristics important for herbivores, to simultaneous experimental increase of carbon dioxide and temperature (ECET) in comparison with both ambient conditions and responses to elevated CO2 (EC) and temperature (ET) applied separately. Our database includes 42 papers describing studies of 31 plant species and seven herbivore species. Nitrogen concentration and C/N ratio in plants decreased under both EC and ECET treatments, whereas ET had no significant effect. Concentrations of nonstructural carbohydrates and phenolics increased in EC, decreased in ET and did not change in ECET treatments, whereas terpenes did not respond to EC but increased in both ET and ECET; leaf toughness increased in both EC and ECET. Responses of defensive secondary compounds to treatments differed between woody and green tissues as well as between gymnosperm and angiosperm plants. Insect herbivore performance was adversely affected by EC, favoured by ET, and not modified by ECET. Our analysis allowed to distinguish three types of relationships between CO2 and temperature elevation: (1) responses to EC do not depend on temperature (nitrogen, C/N, leaf toughness, phenolics in angiosperm leaves), (2) responses to EC are mitigated by ET (sugars and starch, terpenes in needles of gymnosperms, insect performance) and (3) effects emerge only under ECET (nitrogen in gymnosperms, and phenolics and terpenes in woody tissues). This result indicates that conclusions of CO2 elevation studies cannot be directly extrapolated to a more realistic climate change scenario. The predicted negative effects of CO2 elevation on herbivores are likely to be mitigated by temperature increase.
Arctic Siberia: refuge of the Mammoth fauna in the Holocene
QUATERNARY INTERNATIONAL 142: 119-123
Global climate change at the end of Pleistocene led to extinction in the huge territories of Northern Eurasia of the typical representatives of the Mammoth fauna: mammoth, woolly rhinoceros, wild horse, bison, musk-ox, and cave lion. Undoubtedly the Mammoth fauna underwent pressure from Upper Paleolithic humans, whose hunting activity could also have played a role in decreasing the number of mammoths and other representatives of megafauna. Formerly it was supposed that the megafauna of the “Mammoth complex” had become extinct by the beginning of the Holocene. Nevertheless the latest data indicate that extinction of the Mammoth fauna was significantly delayed in the north of Eastern Siberia. In the 1990s some radiocarbon dates established that mammoths existed in the Holocene on Wrangel Island-from 7700 until 3700 yBP. Radiocarbon data show that wild horses inhabited the north of Eastern Siberia 4600-2000 yBP. Muskoxen lived here about 3000 yBP. Some bison remains from Eastern Siberia belong to the Holocene. The following circumstances could promote the survival of representatives of Mammoth fauna. Cool and dry climate in this region promotes the maintenance of steppe associations-the habitats of those mammals. Late Paleolithic and Mesolithic settlements are not found in the Arctic zone of Eastern Siberia from Taimyr Peninsula to the lower Yana River; they are very rare in basins of the Indigirka and Kolyma Rivers. The small number of Stone Age hunting tribes in the northern part of Eastern Siberia was probably another factor that contributed to the survival of some Mammoth fauna representatives. (c) 2005 Published by Elsevier Ltd.
Tropical Atlantic SST history inferred from Ca isotope thermometry over the last 140ka
Hippler, D Eisenhauer, A Nagler, TF
GEOCHIMICA ET COSMOCHIMICA ACTA 70:1 90-100
Exploring the potentials of new methods in palaeothermometry is essential to improve our understanding of past climate change. Here, we present a refinement of the published delta(44/40)Ca-temperature calibration investigating modern specimens of planktonic forarninifera Globigerinoides sacculifer and apply this to sea surface temperature (SST) reconstructions over the last two glacial-interglacial cycles. Reproduced measurements of modern G. sacculifer collected from surface waters describe a linear relationship for the investigated temperature range (19.0-28.5 degrees C): delta(44/40)Ca[parts per thousand] = 0.22 (+/- 0.05)*SST [degrees C] -4.88. Thus a change of delta(44/40) Ca[parts per thousand] of 0.22 (+/- 0.05) corresponds to a relative change of 1 degrees C. The refined delta(44/40) Ca-modern-calibration allows the determination of both relative temperature changes and absolute temperatures in the past. This delta(44/40)Ca(modern)-calibration for G. sacculifer has been applied to the tropical East Atlantic sediment core GeoB1112 for which other SST proxy data are available. Comparison of the different data sets gives no indication for significant secondary overprinting of the delta(44/40)Ca signal. Long-term trends in reconstructed SST correlate strongly with temperature records derived from oxygen isotopes and Mg/Ca ratios supporting the methods validity. The observed change of SST of approximately 3 degrees C at the Holocene-last glacial maximum transition reveals additional evidence for the important role of the tropical Atlantic in triggering global climate change, based on a new independent palaeothermometer. (c) 2005 Elsevier Inc. All rights reserved.
Spreading examination of European corn borer (Ostrinia nubilalis Hbn.) flight types in the background of Peczely’s climate districts
Keszthelyi, S Nowinszky, L Puskas, J
CEREAL RESEARCH COMMUNICATIONS 34:4 1283-1290
European corn borer (ECB) flight and ecotype spread examinations were made in Hungary with the help of catching results of 44 agricultural Jermy light traps (2004). We wondered about alteration of flight types spread borderline as a function of global climate change. Catching data were evaluated by simple mathematical proportional numbers. Catching results originating from different points of the country were compared with Walter-Lieth climate diagram (2004) and Peczely’s Hungarian climate districts. Latter was to reveal correlations of flight types and different climatic districts. The previously published flight alteration tendency of ECB (Keszthelyi 2003, 2004b) continued in 2004. Generation quotients proved this process too. Average generation quotient of populations in South-eastem Hungary was 6, and the top of the same rate in this district was 10,84. The earlier observed ,,one peak flight” type was replaced by,two peaks flight” type in North-western Hungary (average generation quotient of this district: 2,5). The IRIN (relative individual number per one day) shows regressive tendency from South-eastem Hungary to North-westem Hungary (1RIN of 1.district: 6,99; 1RIN of 4.district: 4,69; 1RIN of 10.district: 2,78), but unequivocal conclusions cannot be drawn from these values for places of ecotypes. There is no unambiguous connection between Peczely’s Hungarian climate districts and spread of ECB flight types as proved by the statistical examinations.
Analysis of features of climate change of Huabei area and the global climate change based on heuristic segmentation algorithm
Gong, ZQ Feng, GL Wan, SQ Li, JP
ACTA PHYSICA SINICA 55:1 477-484
Global change science is a new research field, and one of the most important topics of which is the climate change study, to which great importance is attached by all governments of the world, and climatic abrupt change is one of manifestations of climate changes. Nowadays, research of climate change is mainly based on climatic proxy using traditional statistical method. However, climatic system is nonlinear, non-stationary and hierarchical, which makes even harder to detect and analyze abrupt climate changes. As well known, climatic system is made up of several sub-systems, and there may be inherent connections between them; however, there is only a few research methods and theories in this field. This article introduces a new detecting method I the heuristic segmentation algorithm, which is well fitted to nonlinear and non-stationary time series. Then, dealing with northern hemisphere tree rings and Beijing stalagmite based on high and low frequency series, we try to distinguish abrupt changes in different scales and disclose its physial mechanism. Defining a new physical quantity, the abrupt density, and analyzing the distribution characteristics of abrupt changes before and after 1000 a, We take Huabei area’s climatic change as an example to explore the inherent connections between local and global areas.
Hazardous emissions, global climate change and environmental precautions
ENERGY SOURCES PART B-ECONOMICS PLANNING AND POLICY 1:1 75-84
It has been recognized worldwide that the utilization of an enormous amount of fossil fuel has created various adverse effects on the environment, including acid rain and global warming. An increase in average global temperatures of approximately 0.56 K has been measured over the past century. This increase is called global climate change or global warming. The gases with three or more atoms that have higher heat capacities than those of O-2 and N-2 cause the greenhouse effect. Carbon dioxide (CO2) is a main greenhouse gas associated with global climate change. Nitrous oxide (N2O), chlorofluorocarbons (CFCs), methane (CH4) are other important greenhouse gases. Collectively, they are projected to contribute, directly, about as much potential global warming over the next 60 years as CO2. Three trace gases, HFCs, PFCs, and SF6, would be regulated under the 1997 Kyoto Protocol because of their global warming potential and for their potential growth of concentrations in the atmosphere. HFCs have been widely approved as substitutes for CFCs.
Soybean (Glycine max (L.) Merr.) growth and development response to CO2 enrichment under different temperature regimes
Heinemann, AB Maia, AD Dourado-Neto, D Ingram, KT Hoogenboom, C
EUROPEAN JOURNAL OF AGRONOMY 24:1 52-61
The carbon dioxide (CO2) concentration of the global atmosphere has increased during the last decades. This increase is expected to impact the diurnal variation in temperature as well as the occurrence of extreme temperatures. This potentially could affect crop production through changes in growth and development that will ultimately impact yield. The objective of this study was to evaluate the effect of CO2 and its interaction with temperature on growth and development of soybean (Glycine max (L.) Merr., cv. Stonewall). The experiment was conducted in controlled environment chambers at the Georgia Envirotron under three different temperatures and two CO2 regimes. The day/night air temperatures were maintained at 20/15, 25/20 and 30/25 degrees C, while the CO2 levels were maintained at 400 and 700 ppm, resulting in six different treatments. Plants were grown under a constant irradiance of 850 mu moles m(-2) s(-1) and a day length of 12 h; a non-limiting supply of water and mineral nutrients were provided. Five growth analyses were conducted at the critical development stages V4, R3, R5, R6 and R8. No differences in start of flowering were observed as a function of the CO2 level, except for the temperature regime 25/20 degrees C, where flowering for the elevated CO2 level occurred 2 days earlier than for the ambient CO2 level. For aboveground biomass, an increase in the CO2 level caused a more vigorous growth at lower temperatures. An increase in temperature also decreased seed weight, mainly due to a reduction in seed size. For all temperature combinations, final seed weight was higher for the elevated CO, level. This study showed that controlled environment chambers can be excellent facilities for conducting a detailed growth analysis to study the impact on the interactive effect of changes in temperature and CO2 on soybean growth and final yield. (c) 2005 Elsevier B.V. All rights reserved.
Oceans and human health: Emerging public health risks in the marine environment
Fleming, LE Broad, K Clement, A Dewailly, E Elmir, S Knap, A Pomponi, SA Smith, S Gabriele, HS Walsh, P
MARINE POLLUTION BULLETIN 53:10-12 545-560
There has been an increasing recognition of the inter-relationship between human health and the oceans. Traditionally, the focus of research and concern has been on the impact of human activities on the oceans, particularly through anthropogenic pollution and the exploitation of marine resources. More recently, there has been recognition of the potential direct impact of the oceans on human health, both detrimental and beneficial. Areas identified include: global change, harmful algal blooms (HABs), microbial and chemical contamination of marine waters and seafood, and marine models and natural products from the seas. It is hoped that through the recognition of the inter-dependence of the health of both humans and the oceans, efforts will be made to restore and preserve the oceans. (c) 2006 Elsevier Ltd. All rights reserved.
An overview of terrestrial sequestration of carbon dioxide: The United States Department of Energy’s fossil energy R&D program
Litynski, JT Klara, SM McIlvried, HG Srivastava, RD
CLIMATIC CHANGE 74:1-3 81-95
Increasing concentrations of CO2 and other greenhouse gases (GHG) in the Earth’s atmosphere have the potential to enhance the natural greenhouse effect, which may result in climatic changes. The main anthropogenic contributors to this increase are fossil fuel combustion, land use conversion, and soil cultivation. It is clear that overcoming the challenge of global climate change will require a combination of approaches, including increased energy efficiency, energy conservation, alternative energy sources, and carbon (C) capture and sequestration. The United States Department of Energy (DOE) is sponsoring the development of new technologies that can provide energy and promote economic prosperity while reducing GHG emissions. One option that can contribute to achieving this goal is the capture and sequestration of CO2 in geologic formations. An alternative approach is C sequestration in terrestrial ecosystsems through natural processes. Enhancing such natural pools (known as natural sequestration) can make a significant contribution to CO2 management strategies with the potential to sequester about 290 Tg C/y in U.S. soils. In addition to soils, there is also a large potential for C sequestration in above and belowground biomass in forest ecosystems. A major area of interest to DOE’s fossil energy program is reclaimed mined lands, of which there may be 0.63 x10(6)supercript stop ha in the U.S. These areas are essentially devoid of soil C; therefore, they provide an excellent opportunity to sequester C in both soils and vegetation. Measurement of C in these ecosystems requires the development of new technology and protocols that are accurate and economically viable. Field demonstrations are needed to accurately determine C sequestration potential and to demonstrate the ecological and aesthetic benefits in improved soil and water quality, increased biodiversity, and restored ecosystems. The DOE’s research program in natural sequestration highlights fundamental and applied studies, such as the development of measurement, monitoring, and verification technologies and protocols and field tests aimed at developing techniques for maximizing the productivity of hitherto infertile soils and degraded ecosystems.