Irrigation water limits reduce crop resilience to climate change in China

Irrigation is widely regarded as an effective strategy to sustain crop production under climate change, especially as droughts intensify. However, droughts continue to cause substantial yield losses even in irrigated regions, indicating that irrigation alone cannot fully offset climate-induced risks. Most existing studies assessing adaptation strategies assume unlimited water availability, potentially underestimating the constraints imposed by irrigation system capacity. To address this, we developed an enhanced irrigation module in a land surface model (Common Land Model, CoLM) that explicitly accounts for source water availability, including local runoff, nearby rivers, and upstream reservoirs. Using this framework, we reproduced observed irrigation amounts, crop yields, and the stagnation of irrigation benefits during droughts across China. Future projections under a high-emission scenario (SSP585) suggest that intensifying droughts will exacerbate irrigation water gaps, leading to larger crop yield deficits, particularly in heavily irrigated regions. Our results highlight that reliable evaluation of climate adaptation strategies in agricultural systems requires explicit consideration of irrigation water limitations, providing critical guidance for sustainable food production under global change.