Long-term terrestrial aridity changes were detected, attributed and projected using multi-source merged multi-layer soil moisture products and CMIP6 factorial simulations.
By revealing detailed spatiotemporal patterns of human forcings’ impacts on long-term aridity changes, this study advanced current understanding of the changes and causes of terrestrial aridity, provided a basis for drought and flood risk management, and generated results and methodological developments that will be of interest to the scientific community and the broader public.
Significant human contributions to global soil moisture-based drying of the surface soil in August–November and the root-zone soil in September–April over 1971–2016 were identified. The drying mainly occurred in the northern and southern mid-latitudes, and in the summer and autumn seasons in the northern high-latitudes; counteracting wetting occurred in the northern subtropics and in spring in the northern high-latitudes. The anthropogenic impacts were mainly contributed by greenhouse gas emissions. Pseudo-observation constrained future aridity trends under the SSP5-8.5 scenario suggested accelerating drying in the surface soil and in the root-zone soil, except in the spring in the northern high latitudes. These human-induced heterogeneous aridity changes point to greater risks of drought and floods in the future, suggesting the need for latitude- and seasonally dependent mitigation and adaptation measures.