Limiting global warming to 2 °C benefits building climate resilience in rice-wheat systems in India through crop calendar management

CONTEXT Rice-wheat rotation system (RWS) is the most important food production system in South Asia and contributes approximately 50% of the total food consumed in India. Building climate resilience of RWS in the context of global warming is critical to sustainably feeding the ever-increasing population in India. Prior research has shown a large potential for climate change adaptation in rice and wheat production through cropping calendar adjustment, but the climate resilience of rice-wheat systems remains elusive. OBJECTIVE The study aims to project coupled changes in the growing seasons of rice and wheat in RWS under global warming, and evaluate climate resilience of RWS productivity in India through crop calendar adjustment. METHODS We combined an improved Environmental Policy Integrated Climate model with satellite remote sensing data to investigate the coupling of rice and wheat growing seasons in RWS in India. Then, we shifted crop calendars in RWS to simulate optimal planting dates and potential yield changes of rice and wheat under contrasting global warming scenarios. RESULTS AND CONCLUSIONS We show that farmers will face a yield trade-off between monsoon rice and dry-season wheat under high greenhouse gas emission scenarios (4 °C warming by the end of the century) in the Indo-Gangetic Plains (IGP) due to a tighter coupling of crop growing seasons in RWS. Early planting for both monsoon rice and dry-season wheat is recommended in the current climate, but the strategy does not apply to future climate change scenarios in the IGP. Limiting global warming below 2 °C by the end of the century is likely to improve RWS productivity by 14% in irrigated systems and 21% in rainfed systems, and keep sufficient maneuvering space for resilient planting strategies in the future. SIGNIFICANCE Our analysis emphasizes that failure to fulfill the pledges of the Paris Agreement will result in not only higher crop damage but also more challenging climate adaptation planning in RWS in India