PAOC Colloquium – Tamara Pico (UC Santa Cruz)

Out of the ice age: sea level, ice sheets, and megafloods in North America

Although understanding the response of ice sheets to a changing climate is a pressing issue of this century, our current knowledge of past ice-sheet changes remains limited by data sparsity. Over the last deglaciation, we understand global sea-level changes quite well, however, we know little about which ice sheets contributed meltwater at what times. I explore approaches that leverage non-traditional datasets to constrain past ice sheet and sea-level change over the last glacial cycle. For example, I revisit two topics of considerable debate: the expansion of the ice-free corridor between the two North American ice sheets and the flooding of the Bering Strait. I show it is possible to use observations of the Bering Strait flooding as sea-level indicators to fingerprint the timing and location of North American saddle deglaciation.
 
Next, I consider the potential to use past landscapes to infer crustal deformation induced by ice sheet loading. Over the ice-age, glacial isostatic adjustment produces rates of uplift comparable to some of the fastest tectonic uplift rates (~10 mm/yr) in regions hundreds of kilometers away from the maximum ice sheet extent. I investigate the role of glacial isostatic adjustment in the dynamics of Missoula megafloods, the largest known floods on Earth. I consider implications for the erosional history of the Channeled Scablands in eastern Washington and Idaho.

The PAOC Colloquium is a weekly interdisciplinary seminar series that brings together the whole PAOC community. Seminar topics include all research concerning the physics, chemistry, and biology of the atmospheres, oceans and climate, but also talks about e.g. societal impacts of climatic processes. The seminars take place on Monday from 12-1pm. Contact paoc-colloquium-comm@mit.edu for more information and Zoom password.