A BI-HEMISPHERIC PERSPECTIVE ON THE LAST GLACIAL TERMINATION FROM THE SOUTHERN ALPS OF NEW ZEALAND AND THE ALTAI MOUNTAINS OF WESTERN MONGOLIA

The last glacial termination ~18,000 – 11,000 yrs ago represents the last great global warming and the last time CO₂ rose by a substantial amount before the industrial period. An understanding of this remarkable climate event will help hone our understanding of the processes that drove warming to completion and of the climate system sensitivity to natural and human forcing factors, such as atmospheric CO₂. Here, we test possible drivers of the last glacial termination by comparing chronologies of mountain glacier recession in the middle latitudes of both polar hemispheres. Extra-polar mountain glaciers are highly sensitive to atmospheric temperature, and glacier landforms afford insight into past climate conditions. We present ¹⁰Be surface-exposure chronologies and glacial geomorphologic maps of mountain glacier recession since the Last Glacial Maximum in the Southern Alps of New Zealand (44°S, 170°E) and in the Altai Mountains of western Mongolia (49°N, 88°E). On the basis of these chronologies, we will evaluate the relative roles of rising atmospheric CO₂, local insolation forcing, and ocean-atmosphere reorganizations in driving the warming that ended the last ice age.