Land Surface Cooling Induced by Sulfate Geoengineering Constrained by Major Volcanic Eruptions
Plazzotta, Maxime ; Séférian, Roland ; Douville, Hervé ; Kravitz, Ben ; Tjiputra, Jerry
Solar radiation management by stratospheric aerosol injection (SRM-SAI) has been proposed as a possible method to counteract anthropogenic global warming, with climate models suggesting it could reduce substantially global temperature and associated impacts. Its effectiveness as simulated by Earth system models exhibits, however, large uncertainties, implying high risks for natural and human ecosystems. Here we identify an emergent relationship linking the long-term global land surface cooling due to SRM-SAI and the short-term cooling following the twentieth century major volcanic eruptions across an Earth system models ensemble. This emergent relationship, combined with observations and reanalysis data, is used to constrain the global land surface temperature (LT) response to reduced downward solar radiation. Based on these constraints, we find a mean decrease in land surface temperature of 0.44 K·W−1·m2, 20% smaller than the unconstrained multimodel mean. This new estimate may affect how trade-offs between cost, risk, and effectiveness of SRM-SAI might be considered.</p>
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