Dam Regulation Moderates Climate‐Induced Rice Yield Loss in the Mekong‐Tonle Sap Lake System

Abstract Rice, a principal global staple crop, is increasingly threatened by flooding under climate change, placing rice‐dependent economies at risk. Yet the capacity of human activities to mitigate inundation impacts on rice remains insufficiently quantified. Here we develop an integrated agro‐hydrological framework that links climate forcing, hydrological regulation, and farmer decision‐making from a systems perspective. We apply the framework to the rapidly changing Lancang‐Mekong River Basin, focusing on Tonle Sap Lake, where flood‐pulse dynamics strongly shape rice production. Relative to the baseline period (1980–2014), with mean annual inundation‐induced rice losses of US$78 million, average losses decline in the near future (2021–2060) across all SSP scenarios, mainly because inundated area and rice exposure decrease. In the far future (2061–2100), losses increase relative to the near future; they remain below the baseline under SSP1‐2.6 and SSP2‐4.5 but slightly exceed the baseline under SSP5‐8.5. Extreme losses remain possible, with the maximum projected loss reaching US$160 million under far‐future SSP5‐8.5. Future losses are controlled not only by inundation extent and duration, but also by the timing of inundation relative to rice phenology. Losses shift from the reproductive and maturity stages in the baseline period toward the vegetative and reproductive stages in future periods, reflecting earlier flood recession and delayed planting. Reservoir operation substantially reduces inundation‐induced losses, particularly during the reproductive and maturity stages, while planting date adjustment provides additional benefits, especially in the far future. This framework supports climate‐resilient assessment of coupled water‐agriculture systems and adaptation pathways in flood‐dependent rice regions.