T192 Decadal to Century-Scale Proxy Climate Records in High-Altitude and High-Latitude Landscapes

Tuesday, 3 November 2015
8:00 AM - 12:00 PM
Room 340

GSA QUATERNARY GEOLOGY AND GEOMORPHOLOGY DIVISION DISTINGUISHED CAREER AWARD: A REMARKABLE CLIMATE CHANGE IN THE SOUTHERN HEMISPHERE

Paper number: T192-4
Program: Technical Sessions
Time: 8:45 AM – 9:15 AM

Authors

Abstract

How the planet emerged from the depths of the last ice age remains an unresolved problem of paleoclimatology. Here I illustrate that in the Southern Hemisphere this transformation featured a remarkable climate change in which 75% of the glacial-interglacial warming occurred in the interval between 17,800 and 16,500 yrs ago. The data for this conclusion come from glacier-inferred temperature reconstructions in the Andes and the Southern Alps, from tree-line rise in the Chilean Lake District, and from a temperature reconstruction from the new WAIS-Divide Antarctic ice core. These records all reflect sharp and immediate responses to temperature changes in the atmosphere. Together, they indicate a synchronous, rapid, and sustained warming that began 17,800 yrs ago and spanned at least 1100 of longitude and at least 400 of latitude. Comparison of these records shows that the amplitude of the glacial-interglacial temperature change for Antarctica (~120C) was about twice that for middle southern latitudes (~60C), presumably because of the amplifying effect of Antarctica’s sea-ice apron.

This decisive warming that ended the last glaciation in southern latitudes may have resulted solely from the far-field effects, through the bipolar seesaw, of the Northern Hemisphere Heinrich stadial 1. However, the warming had a rapidity, extent, and magnitude suggestive of a switch between stable modes of operation of a climate system that is linked together in a nonlinear fashion and thus is susceptible to rapid reorganizations. In such a case, Heinrich stadial 1 may have served simply as the trigger for such a reorganization.