HR: 13:45h
AN: PP33C-01 INVITED     [Abstracts]
TI: Emiliani Lecture: Tropical Ice Core Evidence for Rapid Holocene Climate Change and Asynchronous Glaciation
AU: * Thompson, L G
EM: thompson.3@osu.edu
AF: Department of Geological Sciences, The Ohio State University, 1090 Carmack Road, Columbus, OH 43210 United States
AU: * Thompson, L G
EM: thompson.3@osu.edu
AF: Byrd Polar Research Center, The Ohio State University, 1090 Carmack Road, Columbus, OH 43210 United States
AB: Unprecedented global changes of the 20th Century have heightened our awareness of human vulnerability to potential climate changes in the next millennium. Half of the Earth's surface area lies between $30\deg$N and $30\deg$S and supports roughly 70$%$ of the world's population. Thus, variations in the occurrence and intensity of large-scale climate phenomena such as the El Ni\~{n}o-Southern Oscillation and monsoons are of significance to humanity. Here meteorological records are short and scarce, but fortunately high resolution proxy climate histories are available from selected high altitude, low- and mid-latitude ice caps. This presentation summarizes the results of a 25-year effort to acquire the high resolution, lower-latitude climate and environmental histories that complement polar ice core records and thereby facilitate a better understanding of the complex linkages between the low and high latitudes. Records from ice caps in Asia, South America and Africa are synthesized to provide a better understanding of (1) the history and mechanics of tropical climate systems and (2) the global significance of the tropical hydrological cycle. These histories provide the long-term perspective essential to distinguish natural variation in the climate system from the anthropogenic influences superimposed during the last century. Tropical ice core records raise additional questions about our understanding of the role of the tropics in global climate change and reveal that the growth (glaciation) and decay (deglaciation) of large ice fields in the lower latitudes is often asynchronous between the hemispheres and with high latitude glaciation that occurs on Milankovitch time scales. These records also document large, abrupt climate disruptions in the tropics at $\sim$5.2 and $\sim$4.2 kyr B.P. The latter, a multi-century drought, was coincident with the ``First Dark Age.'' Unfortunately, today virtually all known tropical glaciers and ice caps are retreating and soon will no longer continue to preserve viable paleoclimatic records.
DE: 3344 Paleoclimatology
DE: 1827 Glaciology (1863)
DE: 1863 Snow and ice (1827)
DE: 1600 GLOBAL CHANGE (New category)
DE: 1620 Climate dynamics (3309)
SC: Paleoceanography and Paleoclimatology [PP]
MN: 2004 AGU Fall Meeting