Speaker: Prof. Wallace Broecker, Lamont-Dohert Earth Observatory, Columbia University. Abstract: The distribution of global rainfall has varied with summer insolation, with mean global temperature, and with difference in temperature between hemispheres. These changes are recorded by paleo-shorelines of closed basin lakes and by oxygen isotopes in cave stalagmites. Based on a preliminary study of records covering the last 25 kyrs, there is a suggestion that as greenhouse gases warm the earth, the temperate drylands will become more arid and the Amazonian rainbelt will undergo a northward shift.
This seminar is part of the EAPS Department Lecture Series.

Prof. Broecker's research interests center on climate systems, especially as they involve the role of oceans in climate change. He places strong emphasis on utilizing isotopes in investigating physical mixing and chemical cycling in the ocean and the climate history as recorded in marine sediments. His publications include: The Glacial World According to Wally (1995); "Chaotic climate," Scientific American (1995); Greenhouse Puzzles (1993, with T. Peng); The Last Deglaciation: Absolute and Radiocarbon Chronologies (1992, edited with E. Bard); "The great ocean conveyor," Oceanography (1991); "What drives glacial cycles?" Scientific American (1990, with G.H. Denton); The Carbon Cycle and Atmospheric CO2: Natural Variations Archean to Present (1985, edited with E.T. Sundquist); and Tracers in the Sea (1982). See his webpage for more info.