ICE, SEA LEVEL AND CONTEMPORARY CLIMATE CHANGE
Global sea level continues to rise as climatic warming drives glacier recession.  For social-political reasons, glaciologists are expected to forecast the net rise of sea level by century's end.  Using review, original analysis, and synthesis, I will examine the major glaciological factors contributing to the rise, and will justify choices for bounds on the net value. The topic raises the question of how environmental scientists should respond to requests for quantitative forecasts when quantitative precision is illusory.

My research efforts emphasize environmental change of polar regions, with a focus on glaciologic problems. The choice of polar glaciology reflects the unique and powerful contributions that this subdiscipline makes to environmental change research. Ice core reconstructions of environmental history offer the most comprehensive, varied, and high-resolution view yet achieved of past environments. The ice sheets themselves are a major control on global sea level and albedo, and on high-latitude atmospheric and oceanic circulations, and on physical landscape characteristics. No other topographic features of this size and importance are changeable on such short time scales. I use a quantitatively rigorous and novel blend of geophysical and geochemical techniques to address questions that are important in this context: How have climatic temperature and atmospheric greenhouse gas concentrations covaried in the past? What is the tempo and magnitude of climate changes in polar regions? What determines the isotopic composition of precipitation? How have the great ice sheets changed in the past, and how will they change in the future? How do they flow? How are microphysical processes in ice manifest at the scale of whole glaciers and ice sheets.