Josefino C. Comiso
Laboratory for Hydrospheric Processes, Code 971
NASA Goddard Space Flight Center, Greenbelt, MD 20771
http://doi.org/10.57043/transnastphl.2000.5375
Abstract
The observed positive trends of anthropogenic CO₂ and other greenhouse gases in the atmosphere has been linked to human activities and may cause a profound influence on climate. Global surface temperatures, as observed by meteorological stations, have been increasing at the rate of 0.4 K per decade during the last century. Surface and satellite data show that warming actually accelerated during the last century. Surface and satellite data show that warming actually accelerated during the recent decade providing evidence that the greenhouse induced change may already be occurring. This phenomenon is studied in detail in the polar regions where climate change signal is expected to be amplified due to feedback effects associated with the high albedo of ice and snow. The 50- to 100-year data records from polar stations show consistently higher warming trends in both regions than global trends. The 20 year satellite record and corresponding in situ data, however, show symmetric effects: a warming and a sea ice retreat in the Arctic but a slight cooling and a sea ice cover advance in the Antarctic. This counter-intuitive observations are actually supported by a previous simulation study of greenhouse warming effects using a global circulation model. Satellite data also reveal large regional variability countries. Ensuing changes in the environment and associated impacts on society may be drastic and costly depending on location. The strategy to mitigate the impacts must include a good understanding of the Earth’s climate system.