In summary, projected soil moisture changes increase with levels of global warming , although there remains substantial disagreement on specific regional changes. In the CMIP6 multi- model ensemble at 4℃ global warming, decreased soil moisture of up to 40% is projected in Amazonia, southern Africa and western Europe in all models . In all other regions, there is no consensus on the sign of projected soil moisture changes, and projected changes at 4℃ global warming include decreases of up to 30% and increases of up to 40%. Projected changes are smaller at lower levels of global warming, with similar geographical patterns of change.
IPCC
Climate Change 2022: Impacts, Adaptation and Vulnerability
IPCC Report