A Potential Surface Warming Regime for Volcanic Super‐Eruptions Through Stratospheric Water Vapor Increases

• Published in: Journal of geophysical research. Atmospheres 2024-07, Vol.129 (13), p.n/a
• Main Authors: Guzewich, Scott D., Oman, Luke D., Colarco, Peter R., Richardson, Jacob A., Whelley, Patrick L., Fauchez, Thomas J., Kopparapu, Ravi K., Bastelberger, Sandra T.
• Format: Article
• Language: English
• Subjects: Absorptivity; Aerosols; Atmospheric chemistry; Basalt; Carbon dioxide; Climate; Climate change; Climate models; Climatic conditions; Cooling; Earth; Emissions; Eruptions; GCM; Global warming; Lower stratosphere; Microphysics; Radiative forcing; Simulation; Stratosphere; Stratospheric warming; Stratospheric water vapor; Sulfates; Sulfur; Sulfur dioxide; Sulfur dioxide emissions; Sulphur; Sulphur dioxide; Surface temperature; Troposphere; Upper troposphere; Volcanic aerosols; Volcanic eruptions; volcano; Water vapor; Water vapour
• ISSN: 2169-897X; 2169-8996
• DOI: 10.1029/2023JD038667

Large volcanic eruptions are known to influence the climate through a variety of mechanisms including aerosol‐forced cooling and warming via emitted CO2. The January 2022 Hunga shallow underwater eruption caused an increase in stratospheric water vapor, and demonstrated how the associated positive radiative forcing can be an important component of an eruption's climate forcing. We present interactive stratospheric aerosol model simulations of super‐volcanic eruptions with a range of SO2 emissions that can produce climate warming through feedback effects produced by a large igneous province (or “flood basalt”) mid‐latitude super‐eruption using Goddard Earth Observing System Chemistry Climate Model climate model simulations. The model experiments suggest total SO2 emissions ≳4,000 Tg/4 Gt generate a multi‐year period of sustained aerosol absorptive local‐heating of the upper troposphere and lower stratosphere and hence produce net climate warming after strong initial cooling. The eruptions produce stratospheric water vapor increases of factors of 8–600. The initiation of these feedbacks within the simulations suggest they could occur for individual stratovolcano eruptions of the scale of the Toba or Tambora eruptions. We note the sensitivity of our results to volcanic sulfate aerosol microphysics and model chemistry. Plain Language Summary Volcanic eruptions are important drivers of climate change throughout Earth's history. Using climate model experiments, we examine how massive volcanic eruptions can produce warmer climate conditions through an increase in stratospheric water vapor. We find that there is a range of volcanic sulfur dioxide emissions that can produce climate warming, but that the stratospheric water vapor increase occurs in all of our model experiments. Key Points Stratospheric water vapor increases by a factor of 8–600 for volcanic SO2 emissions of 1,875–60,000 Tg Volcanic SO2 emissions ≳4,000 Tg can produce net climate warming through feedbacks Absorptive‐heating driven increases to stratospheric water vapor likely becomes the dominant forcing for volcanic super‐eruptions