Scaling up water-saving irrigation reduces yield-scaled greenhouse gas emissions by over one-quarter in China’s rice paddies

Rice cultivation is a major contributor to greenhouse gas (GHG) emissions, primarily driven by flooded irrigation, which exacerbates methane emissions. Although water-saving irrigation technologies have been proposed to mitigate these emissions, their potential impact at scale remains unclear. Here we combine a synthesis of 904 field studies with spatial upscaling using validated Random Forest models (R2: 0.60–0.90) to predict how different irrigation strategies affect Chinese rice agriculture and identify their key spatial drivers. We also evaluated the national impact of scaling up water-saving irrigation through a spatially explicit trade-off analysis that classified grid cells into win-win, lose-lose, win-lose, and lose-win categories. We estimate that water-saving irrigation could increase rice production up to 236.6 Tg yr−1 (a 1.6 % gain from the baseline), while reducing total and yield-scaled GHG emissions to 172.6 Tg yr−1 and 0.73 kg CO2e kg−1, representing reductions of up to 26 % and 28 %, respectively. Widespread adoption of water-saving irrigation increased the proportion of win-win synergy between yield gain and emission reduction to 32.6 % (a 9.9 % increase). However, the persistence of substantial trade-offs underscores the necessity of combining water-saving practices with complementary strategies like optimized nitrogen use, crop genetics, and residue management. Our findings suggest that further scaling up of water-saving irrigation has substantial potential to simultaneously enhance productivity and reduce emissions, provided that regionally tailored, integrated management strategies are adopted.