Biodiversity regulates the asymmetric influence of forest cover gain and loss on land surface temperature

Abstract Land surface temperature (LST) responses to forest gain and loss are highly asymmetric, with stronger cooling per unit gain than warming per unit loss, particularly in tropical and temperate regions. Although this asymmetry has been documented, the mechanisms underlying its spatial heterogeneity remain unclear. Here we integrate satellite-derived LST data with climate, soil, topography, and vegetation data to show that biodiversity is the dominant driver of spatial heterogeneity in this asymmetry. By stabilizing interannual climate variability, biodiversity promotes young tree growth, whose higher evapotranspiration enhances latent heat cooling—the principal mechanism governing asymmetry in tropical and temperate zones. Biodiversity also increases soil nutrient availability, particularly soil organic carbon (SOC), facilitating young tree establishment and growth and amplifying cooling. This SOC-mediated effect is especially important in boreal regions, where vegetation growth is strongly SOC-limited. Our findings emphasize incorporating biodiversity into Earth system models to improve land–climate predictions under global change.