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Seminar talk: Arctic Atmospheric Circulation Changes Caused by the Demise of the Laurentide Ice Sheet

Elizabeth K. Thomas, University at Buffalo, will give a talk at the Bjerknes Centre on October 24.


Short biography

Elizabeth Thomas is an Associate Professor of Geology at the University at Buffalo and a Fulbright Scholar hosted by the University in Bergen until summer 2023. Her current research focus is on the patterns and processes of Arctic climate response to past rapid warming events, filling spatial gaps in high-resolution records in Siberia and Beringia. Thomas holds a BSci from Smith College, a MSci from the University at Buffalo, and a MSci and PhD from Brown University, where she studied orbital-scale dynamics of the East Asian monsoon. Her team uses organic geochemical and stable isotope proxies to reconstruct past water cycle and temperature changes. They combine these records with modern observations and climate and proxy forward models to understand the mechanisms that cause past changes.


The great continental ice sheets, which persisted through the Early Holocene, caused major changes in atmospheric circulation and attendant changes in ocean circulation and regional precipitation. Paleoclimate records spanning these intervals of ice sheet change can provide useful frameworks for the magnitude and mechanisms of change during large shifts in climate boundary conditions. I will present a record of summer temperature and precipitation hydrogen isotope values from Lake CF8 on northeastern Baffin Island spanning the Early Holocene. We find that summer precipitation hydrogen isotope values primarily respond to changes in summer temperature only when the Laurentide Ice Sheet is not present in North America. When the Laurentide Ice Sheet was present, summer precipitation hydrogen isotope values were influenced by changes in moisture sources, likely due to the ice sheet both covering key terrestrial sources of summer moisture to Baffin Island and also causing dynamical changes in atmospheric and ocean circulation. Similar ice-sheet influences will be critical to consider when interpreting paleoclimate records throughout the Arctic, especially during periods of dramatic ice-sheet change.

Time: October 24 at 14:15 PM

Bjerknes lecture room 4020, 4th floor, Jahnebakken 5.