|Abstracts on Global Climate Change|
Scenarios for sea level on the Finnish coast
Johansson, MM Kahma, KK Boman, H Launiainen, J
BOREAL ENVIRONMENT RESEARCH 9:2 153-166
The linkage between global climate change and sea level on the Finnish coast was studied. Scenarios were calculated for the long-term mean sea level in the future, based on the global change scenarios given by the Intergovernmental Panel on Climate Change. The effects of global mean sea level, local land uplift and the water balance of the Baltic Sea were taken into account. The effect of the water balance was estimated with the North Atlantic Oscillation (NAO) index. In most cases the rise in water level is expected to balance the land uplift in the Gulf of Finland, and the past declining trend of the relative sea level is not expected to continue. In the Gulf of Bothnia, the stronger land uplift rate still results in a fall of the relative mean sea level in the future. The uncertainties in the scenarios are large. Scenarios for the intra-annual variability of the sea level were constructed by extrapolating the 20th century trends of increasing variability.
Photosynthetic responses of Larrea tridentata to seasonal temperature extremes under elevated CO2
Naumburg, E Loik, ME Smith, SD
NEW PHYTOLOGIST 162:2 323-330
Elevated CO2 potentially decreases the effects of temperature stress on photosynthesis. Under both freezing and high temperatures previous studies have shown that elevated CO2 can particularly enhance photosynthetic rates, although results from freezing studies are more variable. Here we show gas exchange responses of Larrea tridentata to elevated CO2 over a 6-yr. period when temperature stress events may have had a significant effect on photosynthesis in the field. Nighttime freezing air temperatures decreased subsequent daytime photosynthetic rates, stomatal conductance, and the maximum yield of PSII similarly under ambient and elevated CO2. Further, we found no statistically significant relationship between leaf temperature and photosynthetic enhancement. Overall, the degree of photosynthetic enhancement under elevated CO2 was directly proportional to the response of stomatal conductance to CO2. Thus, elevated CO2 does not significantly affect apparent physiological responses of Larrea to temperature extremes. However, because of the tight relationship between stomatal conductance and photosynthetic enhancement, potential climate change effects on stomatal conductance will significantly influence Larrea performance in the future.
MSA in Beijing aerosol
Yuan, H Wang, Y Zhuang, GS
CHINESE SCIENCE BULLETIN 49:10 1020-1025
Methane sulphonate (MSA) and sulfate (SO42-) the main oxidation products of dimethyl sulfide (DMS), are the target of atmospheric chemistry study, as sulfate aerosol would have important impact on the global climate change. It is widely believed that DMS is mainly emitted from phytoplankton production in marine boundary layer (MBL), and MSA is usually used as the tracer of non-sea-salt sulfate (nss-SO42- ) in marine and coastal areas (MSA/SO42- = 1/18). Many observations of MSA were in marine and coastal aerosols.. To our surprise, MSA was frequently (>60%) detected in Beijing TSP, PM10, and PM2.5 aerosols, even in the samples collected during the dust storm period. The concentrations of MSA were higher than those measured in marine aerosols. Factor analysis, correlation analysis and meteorology analysis indicated that there was no obvious marine influence on Beijing aerosols. DMS from terrestrial emissions and dimethyl sulphoxide (DMSO) from industrial wastes could be the two possible precursors of MSA. Warm and low-pressure air masses and long time radiation were beneficial to the formation of MSA. Anthropogenic pollution from regional and local sources might be the dominant contributor to MSA in Beijing aerosol. This was the first report of MSA in aerosols collected in an inland site in China. This new finding would lead to the further study on the balance of sulfur in inland cities and its global biogeochemical cycle.
Superensemble prediction of regional precipitation over Korea
Kim, MK Kang, IS Park, CK Kim, KM
INTERNATIONAL JOURNAL OF CLIMATOLOGY 24:6 777-790
Seasonal precipitation at the decadal time scale is predicted using the downscaling super ensemble (DSE) method, which is developed by combining the superensemble procedure with a statistical downscaling method in this study. The multimodel data utilized are the long-term integration of six atmosphere-ocean general circulation models (AOGCMs) and the downscaling method is based on the singular value decomposition with the empirical orthogonal function (EOF) truncation to correct the systematic bias in the dynamic models. Interestingly, even though prediction skill in the training period is increased with increasing number of AOGCMs used, the skill is often decreased in the independent period. It is found that prediction skill in the independent period continues to rise when we use an optimal combination of predictors. The optimum combination used in constructing the superensemble model is the super-3 ensemble, which is a combination of three AOGCMs (CCCma, CSIRO, and NCAR) among the six AOGCMs used in this study. In general, the first four EOFs of sea-level pressure (SLP) in the super-3 ensemble are very similar to those of the observed SLP. The dynamic link between Korean winter precipitation and East Asian monsoon circulation in the super-3 ensemble is similar to that of the observed indicating that the super-3 ensemble realistically simulates the circulations in the East Asian monsoon region. The cross-validation for the prediction of the super-3 ensemble shows that the correlation skill score is about 0.49, which is significant at the 5% level. The results provide hope for regional climate prediction in decadal time-scales using superensemble methods together with statistical downscaling. Copyright (C) 2004 Royal Meteorological Society.
Climate change mitigation in Turkey
ENERGY SOURCES 26:6 563-573
One of the most contentious issues in the debate over global climate change is the perceived divide between interests and obligations of developed and developing countries. Equity demands that developed countries act first to reduce emissions. That principle is embedded in the 1992 United Nations Framework Convention on Climate Change and in the 1997 Kyoto Protocol, which sets binding emission targets for developed countries only. With the Protocol now likely to enter into force, the focus will turn increasingly to the question of developing country emissions. Turkey’s high rate of energy-related carbon emissions growth is expected to accelerate, with emissions climbing from 60 million tons in 2002 to almost 220 million tons in 2020. Carbon intensity in Turkey is higher than the western developed country average. Energy-intensive, inefficient industries remain under government control with soft budget constraints, contributing to undisciplined energy use. Planned industrial privatizations may close the oldest and most inefficient operations and modernize surviving ones. Elimination of energy price subsidies could stimulate energy conservation, reducing energy and emissions growth below current projections. This article reviews energy consumption and climate change mitigation in Turkey.
Water level variability and trends in Lake Constance in the light of the 1999 centennial flood
Johnk, KD Straile, D Ostendorp, W
LIMNOLOGICA 34:1-2 15-21
The extreme flood of Lake Constance in 1999 focused attention on the variability of annual lake levels. The year 1999 not only brought one of the highest floods of the last 180 years but also one of the earliest in the season. The 1999 extreme event was caused by heavy rainfall in the alpine and pre-alpine regions. The influence of precipitation in the two distinct regional catchments on lake level variations can be quantified by correlation analysis. The long-term variations in lake level and precipitation show similar patterns. This is seen through the use of spectral analysis, which gives similar bands of spectral densities for precipitation and lake level time series. It can be concluded from the comparison of these results with the analysis of climate change patterns in northern Europe, i.e. the index of the North Atlantic Oscillation, that the regional effects on lake level variations are more pronounced than those of global climate change.
Spatiotemporal influences of climate on altitudinal treeline in northern Patagonia
Daniels, LD Veblen, TT
ECOLOGY 85:5 1284-1296
Tree radial growth and seedling establishment of Nothofagus pumilio at alpine treeline near 40degrees S latitude in Chile and Argentina show time- and site-dependent relationships to interannual- and decadal-scale climate variation. Six treelines were sampled at two spatial scales corresponding to regional and local climates. A shift in climate from cool-wet to warm-dry conditions facilitated comparison of climate-vegetation relationships during two distinct periods: 1957-1976 and 1977-1996. For each treeline, tree radial growth and seedling establishment were correlated against monthly and seasonal temperature, precipitation, moisture availability, and two indices of El Ni (n) over tildeo-Southern Oscillation (ENSO): southern oscillation index (SOI) and sea surface temperature (SST). Four key aspects of climatic influences on N. pumilio radial growth and seedling establishment were as follows. (1) The relationship between krummholz radial growth and temperature variation was nonlinear. (2) Moisture availability was the dominant climatic factor influencing seedling establishment, although temperature-precipitation interactions resulted in variability among study areas. (3) Climate conditions that facilitated Nothofagus pumilio seedling establishment were distinct, and often opposite, from those that enhanced radial growth. (4) The relationships of radial growth and seedling demography with climate and ENSO differed among study areas and have been unstable over the past 40 years. Observed spatial and temporal instabilities in vegetation-climate relationships demonstrate the complexity of treeline dynamics in northern Patagonia under a changing climate. We conclude that a directional increase in temperature, as predicted by current global climate scenarios, will not necessarily result in an upslope expansion of the N. pumilio forests growing at altitudinal treeline in northern Patagonia.