Seminar by Matteo Willeit from Senior scientist, Potsdam Institute for Climate Impact research, Germany
14 July 2025
KST 10:00
The Seminar is being held in Room 1010 (Jasmin) – Integrated mechanical engineering building. Click here for the campus map.
Abstract:
Past glacial periods were characterized by pronounced millennial-scale climate variability, mainly associated with Dansgaard-Oeschger (DO) and Heinrich events, while climate during warm interglacial periods is much more stable. While large iceberg discharges from the Laurentide ice sheet during Heinrich events are intrinsically associated with glacial times, it remains unclear why DO variability is a feature of cold climates and whether a similar mode of variability could operate in a future warmer world. Here we use a fast Earth system model that produces DO events as internal climate variability to suggest that the climate-dependence of the surface buoyancy flux integrated over the northern North Atlantic can explain the occurrence of DO events under cold climate conditions. We also find that an AMOC collapse in response to Heinrich events can trigger deep convection in the Southern Ocean around Antarctica, strongly affecting Southern Hemisphere climate and contributing to millennial-scale climate variability.
In climates warmer than at present we additionally find self-sustained millennial-scale oscillations in the Southern Ocean, suggesting that in a warmer world millennial-scale climate variability could originate from the Southern Hemisphere.
CV Matteo Willeit
I’m a senior scientist at the Potsdam Institute for Climate Impact Research, co-leading the working group on Long-term trajectories in the Earth system. I’m part of the PalMod project on simulating the last glacial cycle and am involved in the Past2Future project aiming at using paleoclimates to constrain the future evolution of the Earth system. I studied Physics with a focus on climate, and obtained a PhD in climate dynamics from the University of Potsdam with a thesis on vegetation and carbon cycle feedbacks. My research interests generally include the dynamics of the Earth system, the interactions between ice sheets and ocean circulation, the stability of the AMOC, millennial-scale climate variability, Quaternary climate variability and long-term future climate evolution.