Response of global land evapotranspiration to climate change, elevated CO2, and land use change

• The climate change signal is detectable in increasing evapotranspiration. • Land use enhances (reduces) evapotranspiration in afforested (deforested) areas. • The dominant role of climate change mainly depends on the impacts of precipitation. Climate change (CLI), elevated CO 2 concentration (CO 2 ), and land use change (LUC) have strongly altered land evapotranspiration (ET) during the recent decades. The fingerprints of these drivers in ET change, however, have not previously been detected due to the lack of these three scenarios from global climate models (GCMs). Here we applied an optimal fingerprint method to detect and attribute ET change by integrated utilization of state-of-the-art global ecosystem models and GCMs. Results indicate that CLI provides the greatest contribution to increasing ET, and its fingerprint is detectable at different timescales. CO 2 reduces ET in most areas covered by forests. LUC decreases ET over the tropics, while increases ET over temperate and high-latitude regions. To further subdivide the impacts of CLI, we extend the Budyko framework to quantify the contribution of precipitation (P) and potential evapotranspiration (PET) and find that the dominant role of CLI mainly depends on the contribution of P.