Xie et al. 2022 used optimal fingerprinting to detect and attribute summer soil moisture changes for the globe and six other regions.

They investigated multiple forcings (GHG, AA, LU) using single-forcing simulations of CMIP6, as well as future changes under different RCP scenarios.

One interesting perspective here is that the selected regions focus on those with strong land-atmosphere interactions (mainly semi-arid regions). In these regions, evapotranspiration is limited by soil moisture, and yet is not so low that the impact on the overlaying atmosphere is negligible.

They demonstrated that summer soil moisture is drying for the majority of the globe, but wetting consistently in Sahel and parts of mid-latitudes of Asia.

The best detected & attributed effect is GHG. AA is detected, but not for the same depths for the two used reanalysis datasets (ERA5 and GLDAS NOAH).

As GHG emissions continues to become larger, the GHG-induced wetting and drying trends are projected to accelerate.

The surface soil also dries faster than the deeper soil, where the increasing atmospheric demand for evapotranspiration may be mitigated by CO2 fertilization effect and increasing water use efficiency of vegetation.

https://www.frontiersin.org/articles/10.3389/feart.2021.745185/full

#detection_and_attribution
#soil_moisture
#land_atmosphere_interactions