COG3

Millennial-scale climate variability during the last two glacial periods, A view from the Southern Hemisphere

Abstract:
Rapid, high-amplitude climate cycles are characteristic of the Northern Hemisphere during the Last Glacial. Dansgaard/Oeschger cycles of rapid warming and more gradual cooling in the high northern altitudes are accompanied by rapid increases and more gradual decreases in precipitation in the Northern Hemisphere tropics. Little information exists, however, about millennial-scale climate change in the Southern Hemisphere tropics prior to the Last Glacial Period. Speleothems from the Peruvian Altiplano are one possible archive of changes in South American Summer Monsoon intensity because oxygen isotopes of rainfall on the Altiplano are primarily controlled by the intensity of rainfall in upstream moisture source region, the Amazon Basin. I will present results of our studies of SASM variability over much of the last two glacial periods. The result show that the Southern Hemisphere tropics also respond very strongly to changes in temperature in the high northern latitudes, but with an anti-phase relationship to the Northern Hemisphere tropics.