Potential impacts of land use and land cover change (LUCC) and climate change on evapotranspiration and gross primary productivity in the Haihe River Basin, China

Both land use and land cover change (LUCC) and global warming play crucial roles in regulating water and carbon exchanges between the surface and atmosphere. However, the individual contributions of LUCC and global warming, particularly in the mid-latitudes, remain poorly understood. This study disentangled the impacts of LUCC and global warming on evapotranspiration (ET) and gross primary productivity (GPP) during 1980–2015 in the Haihe River Basin (HRB), China, using the Community Land Model version 5. The model experiments suggest that decreases in natural vegetation and expansions of croplands in the HRB reduced annual GPP and ET. Conversely, increasing natural vegetation coverage enhanced annual GPP and ET. Neither LUCC nor global warming exhibited a statistically significant ( p  < 0.05) impact on the spatially averaged annual ET during 1980–2015. However, both LUCC and global warming significantly ( p  < 0.05) increased spatially averaged annual GPP. LUCC enhanced the spatially averaged GPP, possibly due to reforestation and afforestation since the late 1990s. Global warming increased GPP mainly due to the CO 2 fertilization effect. When averaging across the whole HRB, LUCC increased ET with a magnitude of approximately 3.5 mm yr −1 between 1980 and 2015, while global warming reduced ET by about 3.0 mm yr −1. On average, LUCC enhanced the spatially averaged annual GPP with a comparable magnitude to global warming. The findings demonstrated that natural vegetation restoration emerges as an important strategy for climate warming mitigation in mid-latitudes experiencing intense anthropogenic disturbances.