Title: Ice core evidence for energy uptake by the Earth’s climate system during AMOC shutdown intervals

Abstract: Evidence from moraines shows that midlatitude mountain glaciers retreated in both hemispheres during the last deglaciation, during Heinrich Stadial 1 (18ka - 14.7 ka).  Somewhat paradoxically, this was a time of extremely cold winters in the North Atlantic and a time when AMOC overturning strength proxies show a reduced or nearly shutdown AMOC.  Here I show recent evidence from kyrpton and xenon atmospheric concentrations reconstructed from air bubbles in ice cores.  These gases permit a direct inference of the mean ocean temperature due to their temperature-dependent solubilities.  Mean ocean heat content increase, in turn, requires that more energy was entering the Earth system than leaving it (after accounting for latent heat uptake by ice melt). This raises the question, will ocean heating increase in the future if the AMOC shuts down, and how will that affect Antarctic ice loss and sea level rise

Speaker Information
Jeff Severinghaus
Scripps Institution of Oceanography
UC San Diego
Eric Rignot
Date and Time: 
Tuesday, October 8, 2019 - 3:30pm
The Jenkins Room | Croul Hall 3101