Regional inequalities of future climate change impact on rice (Oryza sativa L.) yield in China

The implications of climate change for rice yield have significant repercussions for food security, particularly in China, where rice cultivation is diverse, involving various cropping intensities, management practices, and climate conditions across numerous regions. The regional discrepancies in the impact of climate change on rice yield in China, however, are yet to be fully understood. Using the ORYZA(v3) model and future climate data from 2025 to 2084, gathered from ten climate models and three climate change scenarios (RCP2.6, RCP4.5, and RCP8.5), we conducted an investigation into these regional discrepancies. Our findings suggest a projected average decline in rice yield ranging from 3.7 % to 16.4 % under both rainfed and fully irrigated conditions across different scenarios. Central, eastern, and northwestern China could face the most significant climate change impacts on both rainfed and irrigated rice, with yield reductions reaching 41.5 %. In contrast, low levels of climate change under the RCP2.6 scenario may benefit northeastern (2.4 %) and southern (1.0 %) regions for rainfed and irrigated rice, respectively. Fertilization effects from elevated CO2 could counterbalance climate change's negative impact, resulting in yield increases in all Chinese rice-growing regions, excluding the northwest. The primary factor influencing rice yield changes in all regions under the RCP4.5 and RCP8.5 scenarios was temperature. However, precipitation, solar radiation, and relative humidity had notable and sometimes dominant effects, especially under the RCP2.6 scenario. These results highlight the divergent, even contradictory, rice yield responses to climate change across China, underlining the need to account for regional differences in large-scale impact studies. The study's findings can inform future policy decisions regarding ensuring regional and national food security in China.