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Publication Date
16 October 2023

The Role of Interactive Soil Moisture in Land Drying Under Anthropogenic Warming



Relative humidity (RH) is projected to increase over ocean but decrease over land under anthropogenic warming. The land RH decrease was previously attributed to ocean influences on land changes. Here, we show that interactive soil moisture (SM) is necessary and may be sufficient for anthropogenic warming to reduce the land RH. The land RH decrease is absent in simulations with realistic land‐ocean geometry but fixed SM, and present in simulations with interactive SM but no oceans or changes in precipitation minus evaporation. The land RH decrease is coupled to the SM decline and the latter could be understood as a natural response of interactive SM to anthropogenic warming. Specifically, prior to adjustments in SM and RH, evaporation would increase by ∼6% K−1 following the Clausius–Clapeyron relation, outpacing the radiatively constrained ∼2% K−1 precipitation increase. This prior imbalance depletes SM and consequently reduces RH through the coupling between SM and RH.

Zhou, Wenyu, L. Ruby Leung, and Jian Lu. 2023. “The Role Of Interactive Soil Moisture In Land Drying Under Anthropogenic Warming”. Geophysical Research Letters 50 (19). American Geophysical Union (AGU). doi:10.1029/2023gl105308.
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