Sea Ice and Climate Change: Insights from Models and Satellite Data
Claire L. Parkinson
Oceans and Ice Branch
NASA Goddard Space Flight Center
Abstract:
Sea ice limits exchanges between the oceans and the atmosphere,
reflects incoming solar radiation back to space, and has an array of
additional impacts on polar climates and ecosystems. Some of these
impacts produce positive feedbacks within the climate system, and,
indeed, early conceptual models and global climate model (GCM)
simulations both indicated that the positive feedbacks brought about
by snow and ice are likely to produce an enhanced sensitivity to
climate change in the polar regions versus the rest of the globe.
However, as the models have advanced, these indications have proven
to be more robust for the north polar region than the south. The
satellite record over the past three decades shows a sharp contrast
between the changes in the two polar ice covers, although with a high
degree of spatial and interannual variability in both. The Arctic ice
cover, overall, has decreased, garnering considerable scientific and
media attention because of possible connections with global warming.
Along with the overall decreases, however, the data additionally
reveal intriguing spatial and temporal patterns in the Arctic ice
cover changes that suggest possible ties to oscillatory patterns in
the atmosphere. In the Antarctic, the sea ice cover decreased
markedly in the 1970s but, overall, has increased since then. This
talk will review some of the model simulations and the observational
record of the Arctic and Antarctic sea ice covers as revealed from
satellite passive-microwave data.