Assessing the Impact of Land‐Use Types on Historical Dryness/Wetness Trends Over Global Land Areas

ABSTRACT This study investigates the historical influence of individual land‐use types—forest, grassland, barren, cropland, and urban—on global dryness and wetness trends using CMIP6‐LUMIP simulations. By comparing experiments with (historical) and without (hist‐noLu) land‐use forcing and applying ridge regression, we attribute land‐use‐induced changes in temperature, precipitation, potential evapotranspiration (PET), and the Standardised Precipitation Evapotranspiration Index (SPEI) to individual land types. CMIP6 models reasonably reproduce observed PET and SPEI patterns, supporting their use in attribution analysis. Over 1901–2014, land‐use change induced widespread surface cooling, particularly in the Northern Hemisphere, leading to reduced PET and a coherent midlatitude wetting trend in SPEI. In contrast, precipitation responses were weaker and more heterogeneous. Ridge regression results reveal that cropland and grassland expansion contribute to cooling and PET suppression, while barren land intensifies surface warming and drying, especially in arid zones. Forest and urban land show more localised effects, with urban areas in Southeast Asia and North America exhibiting warming and drying tendencies. Regional assessments across 12 hydroclimatic zones reveal strong spatial heterogeneity: forest dominates wet tropics, grassland regulates PET and SPEI trends in semi‐arid regions, barren land drives arid‐region drying, and cropland shapes temperate hydroclimate. These findings highlight PET as a key mediator of land–climate interactions and underscore the importance of land‐use planning for hydroclimatic resilience.