Abstract

The last deglaciation (approx. 21-7ka) was punctuated by several abrupt climatic and sea level changes in which ice sheets are thought to have played an important role. This talk describes the role of the N. American ice sheet in two of the most important event of rapid sea level change: (i) the MWP -1a, a ~ 14-18 m global sea level rise in less than 350 years which coincided with the rapid N. Hemisphere Bolling warming; (ii) the ‘8.2 kyr event’, a century long cooling event attributed to the sudden release of N. American glacial lakes. By combining, climate, ice sheet and sea level modelling with a variety of palaeo-environment data I evaluate (i) the mechanisms that lead to accelerated ice melt and (ii) the impacts of these on the climate. I will present recent efforts to constrain the contribution of the N. American ice sheet to MWP1a from the Bolling warming and a mass balance mechanism named the saddle collapse. Finally, I will introduce the recent plans of the Palaeo Model Intercomparison Project for simulating the climate of the last deglaciation.