DATE: Friday, April 26, 2019 TIME: 2:30 pm (refreshments at 2:15 pm) PLACE: ENR building, room 223 14 College Farm Road, New Brunswick, NJ
Clay Tabor
Department of Geography, University of Connecticut
Exploring the Climate Responses to the Asteroid Impact at the Cretaceous-Paleogene Boundary
Prolonged low light and cold temperatures at Earth's surface are hypothesized effects of the Chicxulub impact at the end of the Cretaceous. However, debate remains about the causes and consequences of this "impact winter". Here, we use an Earth system model to compare responses from impact-driven emissions of soot, SO2, and dust. We show that, although soot and SO2 emissions can produce years of extreme cold and drought, only soot is capable of reducing surface light to below the photosynthetic threshold for many months. Given the pattern of extinction, we support evidence for widespread fires post-impact and suggest that soot was an important driver of the end-Cretaceous extinction. We identify polar coasts and the surrounding open oceans as regions likely to have experienced the least biotic disruption from the impact winter.