During the last deglaciation (21-7 ka), vast ice sheets that once stretched across much of North America and Eurasia melted away, and the Greenland and Antarctic ice sheets also lost mass. This transition from the previous glacial to current interglacial conditions was punctuated by several abrupt sea level and climate changes, what was the role of the melting ice sheets in driving these events?
In this seminar, Lauren Gregoire will discuss mechanisms of ice sheet instability, presenting case studies of rapid ice sheet collapse. This will include the opening of an ice free corridor through the North American Ice Sheet (associated with the fastest major sea level rise ever recorded, Meltwater Pulse 1a) and the demise of the British and Irish Ice Sheet. She will also discuss how models and geological measurements can be brought together to quantify uncertainties in past and future environmental changes.
Ruza Ivanovic will explore the effect of the ice sheet meltwater on ocean circulation and climate, focussing on two abrupt events: Meltwater Pulse 1a, when sea levels rose by 12-22 m in less than 350 years, and the onset of Heinrich Stadial 1, when Atlantic Overturning Circulation suddenly weakened and the Northern Hemisphere cooled. She will examine the competing impact of Northern versus Southern Hemisphere meltwater pulses to the ocean, and the influence of longer term melting during the early deglaciation.