Attribution of Global Soil Moisture Drying to Human Activities: A Quantitative Viewpoint

Abstract

Abstract Anthropogenic impacts on widespread global soil moisture (SM) drying in the root zone layer during 1948–2005 were evaluated based on the Global Land Data Assimilation System version 2 (GLDAS‐2) and global climate models from the Coupled Model Intercomparison Project Phase 5 using trend analysis and optimal fingerprint methods. Both methods show agreement that natural forcing alone cannot drive significant SM drying. There is a high probability (≥90%) that the anthropogenic climate change signal is detectable in global SM drying. Specifically, anthropogenic greenhouse gas forcing can lead to global SM drying by 2.1 × 10 −3 m 3 /m 3 , which is comparable to the drying trend seen in Global Land Data Assimilation System version 2 (2.4 × 10 −3 m 3 /m 3 ) over the past 58 years. Global SM drying is expected to continue in the future, given continuous greenhouse gas emissions.