Climate change and human activities could induce environmental changes at the regional scale through altering land surface and subsurface states and fluxes. A team of scientists, including U.S. Department of Energy researchers at Pacific Northwest National Laboratory, investigated for the first time the effects of climate change and groundwater-fed irrigation on the land surface and subsurface hydrology in the North China Plain (NCP), one of the most vulnerable regions to climate change and human perturbations in China. Using three climate-change scenarios and one irrigation scenario, the team performed simulations using the Community Land Model 4.0. They found human water use tends to dominate the subsurface water balance in the NCP. Moreover, irrigation appears to have much larger effects on the top layer soil moisture whereas increase in precipitation associated with climate change exerts more influence on lower layer soil moisture. Groundwater exploitation, which removed a large amount of groundwater from the aquifer and applied it to the soil surface, has significantly altered the water availability and distribution in the NCP. This study highlights the importance of accurately accounting for the effects of human water use. The results provide insights to effective measures for adapting to environmental changes that are induced by climate change and human water use for this region.