Volcanic Climate Warming through Radiative and Dynamical Feedbacks of SO2 Emissions

Volcanic flood basalt eruptions have been linked to or are contemporaneous with major climate
disruptions, ocean anoxic events, and mass extinctions throughout at least the last 400M years of
Earth’s history. Previous studies and recent history have shown that volcanically-driven climate
cooling can occur through reflection of sunlight by H2SO4 aerosols, while longer-term climate
warming can occur via CO2 emissions. We use the Goddard Earth Observing System Chemistry-
Climate Model to simulate a four-year duration volcanic SO2 emission of the scale of the Wapshilla
Ridge member of the Columbia River Basalt eruption. Brief cooling from H2SO4 aerosols is
outweighed by dynamically and radiatively driven warming of the climate through a three orders
of magnitude increase in stratospheric H2O vapor.