Abstracts on Global Climate Change

Jan 2005

Morphogenesis of the branching reef coral Madracis mirabilis

Kaandorp, JA Sloot, PMA Merks, RMH Bak, RPM Vermeij, MJA Maier, C


Understanding external deciding factors in growth and morphology of reef corals is essential to elucidate the role of corals in marine ecosystems, and to explain their susceptibility to pollution and global climate change. Here, we extend on a previously presented model for simulating the growth and form of a branching coral and we compare the simulated morphologies to three-dimensional (313) images of the coral species Madracis mirabilis. Simulation experiments and isotope analyses of M. mirabilis skeletons indicate that external gradients of dissolved inorganic carbon (DIC) determine the morphogenesis of branching, phototrophic corals. In the simulations we use a first principle model of accretive growth based on local interactions between the polyps. The only species-specific information in the model is the average size of a polyp. From flow tank and simulation studies it is known that a relatively large stagnant and diffusion dominated region develops within a branching colony. We have used this information by assuming in our model that growth is entirely driven by a difftision-limited process, where DIC supply represents the limiting factor. With such model constraints it is possible to generate morphologies that are virtually indistinguishable from the 3D images of the actual colonies.

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Global biomass mapping for an improved understanding of the CO2 balance - the Earth observation mission Carbon-3D

Hese, S Lucht, W Schmullius, C Barnsley, M Dubayah, R Knorr, D Neumann, K Riedel, T Schroter, K


Understanding global climate change and developing strategies for sustainable use of our environmental resources are major scientific and political challenges. In response to an announcement of the German Aerospace Center (DLR) for a national Earth observation (EO) mission, the Friedrich-Schiller University Jena and the JenaOptronik GmbH proposed the EO mission Carbon-3D. The data products of this mission will for the first time accurately estimate aboveground biomass globally, one of the most important parameters of the carbon cycle. Simultaneous acquisition of multiangle optical with Light Detection and Ranging (LIDAR) observations is unprecedented. The optical imager extrapolates the laser-retrieved height profiles to biophysical vegetation maps. This innovative mission will reduce uncertainties about net effects of deforestation and forest regrowth on atmospheric CO2 concentrations and will also provide key biophysical information for biosphere models. (C) 2004 Elsevier Inc. All rights reserved.

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Climate change impacts and vegetation response on the island of Madagascar

Ingram, JC Dawson, TP


The island of Madagascar has been labelled the world’s number one conservation ‘hot spot’ because of increasing anthropogenic degradation of its natural habitats, which support a high level of species endemism. However, climatic phenomena may also have a significant impact upon the island’s flora and fauna. An analysis of 18 years of monthly satellite images from the National Oceanographic and Atmospheric Administration’s (NOAA) Advanced Very High Resolution Radiometer (AVHRR) have demonstrated that there is a dynamic pattern in Madagascar’s vegetative cover both annually and seasonally throughout 1982-1999. Over interannual time-scales, we show that this vegetation response, calculated using the normalized difference vegetation index (NDVI), has a strong negative correlation with the El Nino Southern Oscillation (ENSO), which can be attributable to drought events and associated wildfires. Global climate change is predicted to increase the frequency of the ENSO phenomenon, resulting in further decline of Madagascar’s natural environment.

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Plausible impact of global climate change on water resources in the Tarim River Basin

Chen, YN Xu, ZX


Combining the temperature and precipitation data from 77 climatological stations and the climatic and hydrological change data from three headstreams of the Tarim River: Hotan, Yarkant, and Aksu in the study area, the plausible association between climate change and the variability of water resources in the Tarim River Basin in recent years was investigated, the long-term trend of the hydrological time series including temperature, precipitation, and streamflow was detected, and the possible association between the El Nino/Southern Oscillation (ENSO) and these three kinds of time series was tested. The results obtained in this study show that during the past years, the temperature experienced a significant monotonic increase at the speed of 5%, nearly 1 degrees C rise; the precipitation showed a significant decrease in the 1970s, and a significant increase in the 1980s and 1990s, the average annual precipitation was increased with the magnitude of 6.8 mm per decade. A step change occurred in both temperature and precipitation time series around 1986, which may be influenced by the global climate change. Climate change resulted in the increase of the streamflow at the headwater of the Tarim River, but the anthropogenic activities such as over-depletion of the surface water resulted in the decrease of the streamflow at the lower reaches of the Tarim River. The study result also showed that there is no significant association between the ENSO and the temperature, precipitation and streamflow.

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Four new species of Lobulia (Lacertilia : Scincidae) from high altitude in New Guinea

Greer, AE Allison, A Cogger, HG


Four new species of scincid lizards in the genus Lobulia are described from high elevations (>= 2350 m) in New Guinea. Some of the features that may permit these skinks to live at high elevation are: dark color pattern, “tinted” lower eyelids and live-bearing reproductive mode. All of the species may be threatened by global climate warming. The generic concept of Lobulia is discussed and a key to the species provided.

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Mapping environments at risk under different global climate change scenarios

Saxon, E Baker, B Hargrove, W Hoffman, F Zganjar, C


All global circulation models based on Intergovernmental Panel on Climate Change (IPCC) scenarios project profound changes, but there is no consensus on how to map their environmental consequences. Our multivariate representation of environmental space combines stable topographic and edaphic attributes with dynamic climatic attributes. We divide that environmental space into 500 unique domains and map their current locations and their projected locations in 2100 under contrasting emissions scenarios. The environmental domains found across half the study area today disappear under the higher emissions scenario, but persist somewhere in it under the lower emissions scenario. Locations affected least and those affected most under each scenario are mapped. This provides an explicit framework for designing conservation networks to include both areas at least risk (potential refugia) and areas at greatest risk, where novel communities may form and where sentinel ecosystems can be monitored for signs of stress.

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Selective adsorption of a substance derived from saccharides onto synthetic resin particles

Hattori, H Tajima, K Chang, HT Murayama, T Furuya, E


Most, if not all, of the chemicals and chemical products are made using crude oils as the feedstock. However, this feedstock is decreasing and the utilization of it is causing global climate change. An alternative feedstock must be developed to alleviate these problems. Saccharides (sugars) meet these requirements partly because many useful intermediates and products can be obtained in the presence of an acid. In the case when D-fructose reacts with concentrate hydrochloric acid, 5-hydroxymethyl-furfural (HMF) is formed as the primary product. HMF is well known as one of many useful chemicals from biomass. However, it reacts further to form a HMF dimmer, and it also decomposes to smaller molecules such as levulinic acid. This kind of complex reaction is difficult to control through process variables including temperature, time, pressure, and solvent, in order to obtain selectively a specific product. In this study, a method of direct reaction control using adsorption in the same vessel. The results show that HMF dimmer can be selectively adsorbed onto synthetic resin particles. The results are almost the same as those obtained from a phenolics-carbonaceous adsorbent system.

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Monitoring the oceanic flow between Africa and Antarctica: Report of the first GoodHope cruise

Ansorge, IJ Speich, S Lutjeharms, JRE Goni, GJ Rautenbach, CJD Froneman, PW Rouault, M Garzoli, S


THE SOUTHERN OCEAN PLAYS A MAJOR role in the global oceanic circulation, as a component of the Meridional Overturning Circulation, and it is postulated that it has a great influence on present-day climate. However, our understanding of its complex three-dimensional dynamics and of the impact of its variability on the climate system is rudimentary. The newly constituted, international GoodHope research venture aims to address this knowledge gap by establishing a programme of regular observations across the Southern Ocean between the African and Antarctic continents. The objectives of this programme are fivefold: (1) to improve understanding of Indo-Atlantic inter-ocean exchanges and their impact on the global thermohaline circulation and thus on global climate change; (2) to understand in more detail the influence these exchanges have on the climate variability of the southern African subcontinent; (3) to monitor the variability of the main Southern Ocean frontal systems associated with the Antarctic Circumpolar Current; (4) to study air-sea exchanges and their role on the global heat budget, with particular emphasis on the intense exchanges occurring within the Agulhas Retroflection region south of South Africa, and (5) to examine the role of major frontal systems as areas of elevated biological activity and as biogeographical barriers to the distribution of plankton. We present here preliminary results on the physical and biological structure of the frontal systems using the first GoodHope transect that was completed during February-March 2004.

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Discrepancy of global climate change over continents and oceans

Byshev, VI Neiman, VG Romanov, YA


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Preserving biodiversity under current and future climates: a case study

Coulston, JW Riitters, KH


Aim The conservation of biological and genetic diversity is a major goal of reserve systems at local, regional, and national levels. The International Union for the Conservation of Nature and Natural Resources suggests a 12% threshold (area basis) for adequate protection of biological and genetic diversity of a plant community. However, thresholds based on area may protect only a small portion of the total diversity if the locations are chosen without regard to the variation within the community. The objectives of this study were to demonstrate methods to apply a coarse-filter approach for identifying gaps in the current reserve system of the Psuedotsuga menziesii (Douglas-fir) forest type group based on current climatic conditions and a global climate change scenario. Location Western United States. Method We used an ecological envelope approach that was based on seven bioclimatic factors, two topographic factors, and two edaphic factors. Multivariate factor analysis was then used to reduce the envelope to two dimensions. The relative density of habitat and protected areas were identified in each part of the envelope based on the current climate and potential future climate. We used this information to identify gaps in the reserve system. Results Although the protected areas occurred in all parts of the envelope, most existed in colder and drier areas. This was true for both the current climate and potential future climate. Main conclusion To protect more of the ecological envelope, future conservation efforts would be most effective in western Oregon, north-western Washington, and north-western California.

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Global climate change and soil carbon stocks; predictions from two contrasting models for the turnover of organic carbon in soil

Jones, C McConnell, C Coleman, K Cox, P Falloon, P Jenkinson, D Powlson, D


Enhanced release of CO2 to the atmosphere from soil organic carbon as a result of increased temperatures may lead to a positive feedback between climate change and the carbon cycle, resulting in much higher CO2 levels and accelerated global warming. However, the magnitude of this effect is uncertain and critically dependent on how the decomposition of soil organic C (heterotrophic respiration) responds to changes in climate. Previous studies with the Hadley Centre’s coupled climate-carbon cycle general circulation model (GCM) (HadCM3LC) used a simple, single-pool soil carbon model to simulate the response. Here we present results from numerical simulations that use the more sophisticated ‘RothC’ multipool soil carbon model, driven with the same climate data. The results show strong similarities in the behaviour of the two models, although RothC tends to simulate slightly smaller changes in global soil carbon stocks for the same forcing. RothC simulates global soil carbon stocks decreasing by 54 Gt C by 2100 in a climate change simulation compared with an 80 Gt C decrease in HadCM3LC. The multipool carbon dynamics of RothC cause it to exhibit a slower magnitude of transient response to both increased organic carbon inputs and changes in climate. We conclude that the projection of a positive feedback between climate and carbon cycle is robust, but the magnitude of the feedback is dependent on the structure of the soil carbon model.

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