Future projections of rice exposure to cold stress in China throughout the 21st century

Rice exposure to cold stress will be alleviated by the decrease of cold extremes under climate change. The disappearance time of cold exposure and its response to different potential scenes in the 21st century, should be particularly important to make long-term adaptations in China. Given these issues unresolved, here we assessed the decadal changes of rice exposure to cold stress in China throughout the 21st century, and compared the patterns under different combinations of Representative Concentration Pathways (RCP) scenarios, rice phenology shifts and cold tolerance enhancements. Under RCP4.5 with no changes in rice phenology and cold tolerance (i.e., the baseline scene), cold exposure would disappear mainly after the 2030s, 2040s, 2060s and 2080s in Liaoning, Fujian, Jilin and Hunan, respectively. But in Heilongjiang, northern Yunnan, southern Sichuan, western Hunan and northwestern Zhejiang, cold exposure would remain until the end of this century. Compared with the baseline pattern in these provinces, RCP8.5 and cold-tolerance enhancements would make cold exposure disappear 2-3 decades early and reduce the intensity by more than 40%. In southern China, when rice thermal-sensitive stage is moved 10/15 days forward, the disappearance of cold exposure would be 2-4 decades early relative to the baseline pattern. Comparison of the patterns under the baseline scene and other potential scenes suggests cautious optimism about the effectiveness of adjustments in crop phenology and provides quantitative support to the enhancement in cold tolerance. This has broad implications for the research community relative to adaptation planning under climate change.