Seminar: "A 'seesaw rebound' linked to ocean heat release and Greenland ice melt during the Last Interglacial", by Luke Skinner

The Ocean's Challenge groups are organizing a new seminar.
 

Seminar: "A ‘seesaw rebound’ linked to ocean heat release and Greenland ice melt during the Last Interglacial"

Speaker: Luke Skinner, University of Cambridge
 

Date: Thursday, February 8th, 2024
Time: 1pm
Venue: Room Z/033 and online  https://us02web.zoom.us/j/81681944336?pwd=VlpBNnl6M1l3cUJaN3BROTI3N1I3Zz09

Global sea-level was higher during the Last Interglacial (LIG) by some metres, with a significant portion of this arising from Greenland ice sheet (GrIS) melt. Most attempts to explain Greenland mass loss have focussed on either the effects of slow equilibration with intensified summer insolation during the LIG, or else the effects of marine-based ice sheet instabiliities that were triggered during the preceding deglaciation. These explanations place the bulk of excess GrIS melt either very late in the LIG or prior to its onset. Here we document an overshoot in North Atlantic temperatures and mid-latitude precipitation at the onset of the LIG, which we attribute to a northward 'rebound' of the thermal bipolar-seesaw, resulting in the release of previously stored heat from the ocean interior.  Such heat storage and release is a robust feature of modelled overturning circulation (AMOC) perturbations, which cause an overshoot in global energy balance and mean atmospheric temperature upon AMOC resumption. Ice sheet simulations further demonstrate that transient warming in the North Atlantic region can have a significant impact on Greenland ice melt. This work emphasizes that abrupt transient changes in ocean-atmosphere heat transfer may have played a hitherto under-appreciated role in long-term global climate and sea-level change, with further implications for the long-term stability of Greenland ice under anthropogenic ‘overshoot’ warming scenarios.
 

Dr Luke Skinner is a Professor of Earth System Science at the University of Cambridge. His research looks at the role of ocean circulation in past climate change, including in particular its impacts on the carbon cycle and the transport of heat across the globe. Much of his work involves the hand selection of tiny microfossils from marine sediment cores, for subsequent purification and geochemical analysis. Ultimately, his research aims to provide a ‘geological’ basis for understanding and modeling the complex interplay between the carbon cycle and ocean–atmosphere dynamics in the climate system.