C11E-04:
Modest response of the southern Greenland ice sheet to the Holocene Thermal Maximum
Monday, 15 December 2014: 8:45 AM
Nicolaj K Larsen1, Kurt Henrik Kjaer2, Benoit Lecavalier3, Anders A Bjork2, Philippe Huybrechts4, Kristian K Kjeldsen2, Karen-Luise Knudsen1, Jesper Olsen1 and Bent Odggard1, (1)Aarhus University, Aarhus, Denmark, (2)Natural History Museum, Copenhagen, Denmark, (3)Memorial University of Newfoundland, St John's, Canada, (4)Vrije Universiteit Brussels, Brussels, Belgium
Abstract:
To determine the longterm sensitivity of the Greenland ice sheet to a warmer climate, we explored how the southern Greenland ice sheet responded to climatic changes the last 10,000 years and in particular the Holocene Thermal Maximum (HTM), when local atmospheric temperatures in Greenland were 2-4°C higher than the present. We have used a number of threshold lakes to show that the ice margin was retracted behind its present-day extent in all sectors for a limited period between ~7 and 5 cal. kyr BP and in most sectors also from ~1.5 to 1 cal. kyr BP, in response to higher atmospheric and ocean temperatures. Ice-sheet simulations constrained by observations show good correlation with the timing of minimum ice volume indicated by the threshold lake observations. The simulated volume reduction was 0.11 to 0.19 m sea-level equivalent with centennial ice loss rates of ~87-105 Gt/yr during the HTM. Our results provide an estimate of the long-term rates of volume loss that can be expected in the future as regional air and ocean temperatures approach those reconstructed for the HTM.
