Navigating the climate consequences of irrigation-led rice intensification

Rice provides a foundation for global food security with emerging evidence suggesting that meeting future production demands will require increasing irrigation use in regions such as South Asia and Sub-Saharan Africa where untapped yield potential is high. Consequently, increasing water use in rice may be an unforeseen driver of higher global methane emissions. Here we use Eastern India as an exemplar region to estimate yield and greenhouse gas (GHG) implications of irrigation-led intensification with a model-based data assimilation and scenario approach. Results suggest that if intensification (ca. 2 t ha ^-1 ) is achieved with continuous flood irrigation, current baseline emissions (4.1 t CO₂-eq ha ^-1 ) are anticipated to double (8.8 t CO₂-eq ha ^-1 ) with more moderate increases predicted with precision irrigation practices such as alternate wetting and drying (7.0 t CO₂-eq ha ^-1 ). Robust strategies for achieving effective water management are needed to avoid the most damaging climate impacts of rice intensification.