RECENT CLIMATE CHANGE IN RESPONSE TO VOLCANIC EXPLOSIVITY: DOES VEI MATTER?

The release of sulfur-containing gases such as SO₂ and H₂S from volcanic eruptions has the potential to affect global climate patterns. These gases undergo reactions in the atmosphere to produce H₂SO₄—an aerosol that reduces solar insolation reaching Earth’s surface and may reside in the stratosphere for years after formation. In contrast, aerosol in the troposphere has a much shorter residence time and therefore little-to-no effect on global climate. Due to variable thickness of the troposphere, eruptions nearest to the poles have greater potential to inject S-containing gases into the stratosphere than eruptions closer to the equator. Observations of ice cores, supplemented with other means of assessing volcanic activity, are used to understand how large volcanic eruptions affect climate on timescales ranging from days to years. In order to understand what eruption parameters could potentially affect regional and global climate and the importance each parameter plays, we compare sulfur emissions, VEI (Volcanic Explosivity Index), maximum plume height, latitude, and observed temperature changes for eruptions that had a VEI ≥4 over the last 150 years. We found no correlation between volume of sulfur emissions and VEI, sulfur emissions and plume height, or plume height with respect to VEI. These findings suggest that sulfur emissions are not dependent on erupted material or gas volume. Instead, the metrics investigated here hint at a more complicated interaction of these—and potentially other—factors. The next steps in this project are to correlate these eruption results to climate change over the same period of time in order to determine patterns with any specific volcanic eruptions.