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Publication Date
1 December 2021

Human-caused long-term changes in global aridity



Widespread aridification of the land surface causes substantial environmental challenges and is generally well documented. However, the mechanisms underlying increased aridity remain relatively underexplored. Here, we investigated the anthropogenic and natural factors affecting long-term global aridity changes using multisource observation-based aridity index, factorial simulations from the Coupled Model Intercomparison Project phase 6 (CMIP6), and rigorous detection and attribution (D&A) methods. Our study found that anthropogenic forcings, mainly rising greenhouse gas emissions (GHGE) and aerosols, caused the increased aridification of the globe and each hemisphere with high statistical confidence for 1965–2014; the GHGE contributed to drying trends, whereas the aerosol emissions led to wetting tendencies; moreover, the bias-corrected CMIP6 future aridity index based on the scaling factors from optimal D&A demonstrated greater aridification than the original simulations. These findings highlight the dominant role of human effects on increasing aridification at broad spatial scales, implying future reductions in aridity will rely primarily on the GHGE mitigation.

Chai, Rongfan, Jiafu Mao, Haishan Chen, Yaoping Wang, Xiaoying Shi, Mingzhou Jin, Tianbao Zhao, Forrest M. Hoffman, Daniel M. Ricciuto, and Stan D. Wullschleger. 2021. “Human-Caused Long-Term Changes In Global Aridity”. Npj Climate And Atmospheric Science 4. doi:10.1038/s41612-021-00223-5.
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