Recent climate change strengthens the local cooling of European forests

Forests exhibit cooling or warming effects compared to adjacent openlands through biophysical processes. The local temperature effects are predicted by earth system models to evolve in response to climate change. However, these temporal dynamic patterns remain unconstrained by observations and have not been detected in historical records. Here, we provide satellite evidence of emergent negative trends in local land surface temperature (LST) effects of European forests from 2003–2023. The daytime cooling effects have significantly intensified in both winter (-0.17 K/decade) and summer (-0.22 K/decade). The enhanced winter cooling is attributed to the reduced shortwave radiative forcing in forests due to decreasing snow cover. In the summertime, the vegetation physiological response to increased atmospheric vapor pressure deficit boosts evaporative cooling in forests. The negative trends in LST effects of European forests are roughly supported by four state-of-the-art earth system models. However, considerable biases and intermodel spread in the representation of underlying biophysical processes. Given the continued climate change, we emphasize the need to consider their impacts on biophysical effect dynamics when comprehensive forest-related climate mitigation policies are formed.