Revisiting irrigation impacts on the North China Plain: Accounting for water resource limitations

Agricultural irrigation can strongly modify land–atmosphere interactions and regional climate, especially in densely irrigated areas. The North China Plain, the largest irrigated region in China, has experienced significant irrigation-driven changes in local temperature, precipitation, and extreme events. Previous studies often oversimplify irrigation by assuming constant application rates or neglecting water resource limitations, which can lead to biased estimates of irrigation-induced climate effects. To address this, we developed an enhanced irrigation module within a land surface model (Common Land Model, CoLM), coupled with the Community Regional Earth System Model (CRESM), explicitly representing irrigation demand, water availability constraints, and application methods. Using this framework, we successfully reproduced observed surface temperature, precipitation, irrigation amounts, and crop yields across the North China Plain. Our results show that accounting for water-limited irrigation reduces the overestimation of the intensity and frequency of extreme events found in simulations that ignore resource constraints. Furthermore, considering irrigation water limitations alters the simulated regional temperature and precipitation patterns, which in turn affects projections of future agricultural water demand. This study demonstrates that explicitly accounting for water–agriculture interactions is essential for accurately simulating irrigation impacts, supporting more informed strategies for sustainable water and agricultural management under climate change.