RCP8.5气候变化情景下21世纪印度粮食单产变化的多模式集合模拟

基于跨部门影响模型比较计划（ISI-MIP）中20种气候模式与作物模型组合的模拟结果,预估了RCP 8.5排放情景下21世纪印度小麦和水稻单产变化。研究发现：① 多模式集合模拟结果基本再现了印度小麦和水稻单产的空间差异;同时,再现了小麦和水稻单产对温度和降水变化的响应特征：与温度呈负相关,与降水呈正相关。② RCP 8.5情景下,水稻和小麦生长季温度和降水均呈增加趋势,小麦生长季的温度、降水增加幅度大于水稻。空间上,温度增加幅度自北向南逐渐减小,降水增幅则逐渐增加,并且小麦种植区升温幅度大于非种植区,降水增幅则少于非种植区,水稻种植区升温幅度小于非种植区,降水增幅则多于非种植区。③ RCP 8.5情景下,小麦和水稻单产均呈下降趋势,21世纪后半叶尤为明显。小麦单产的下降速度明显大于水稻,其中21世纪前半叶小麦和水稻单产下降速度约分别为1.3%/10a （P < 0.001）和0.7%/10a （P < 0.05）,后半叶分别增至4.9%/10a （P < 0.001）和4.4%/10a （P < 0.001）。小麦和水稻单产变化存在明显的空间异质性,小麦单产的最大下降幅度出现在德干高原西南部,降幅约60%,水稻单产最大下降幅度出现在印度河平原北部,降幅约50%。这意味着未来气候变化情景下印度粮食供给将面临较大的挑战。

Multi-model ensemble projection of crop yield of India under RCP 8.5 climate change scenario during the 21st century

Using the multi-model ensemble projections of wheat and rice in India during the 21st century from the Inter-Sectoral Impact Model Intercomparison Project, this study assessed the future changes in crop yield under the RCP 8.5 emission scenario. The results show that the multi-model ensemble simulations generally reproduce the spatial variability in crop yield that is represented by ground measurements. Furthermore, the simulations reproduce the response of crop yield to climate changes, which is characterized by negative correlations between crop yield and temperature and positive correlations between crop yield and precipitation. Under the RCP8.5 emission scenario, temperature and precipitation during the growing season of wheat and rice will increase. Generally, temperature will increase at a higher rate than precipitation; the increases in temperature and precipitation during the wheat growing season will be stronger than that during the rice growing season. In terms of spatial dimension, the increase in temperature will be weakened gradually from the north to the south, while that of precipitation will be intensified gradually from the north to the south. Temperature increase in the wheat producing areas will be stronger than that in the wheat non-producing area, while precipitation increase in the wheat producing areas will be weaker than that in the wheat non-producing areas. However, the scenario is predicted to be reversed for the rice producing areas. In response to the climate changes, wheat and rice yields will decrease in the 21st century, particularly in the second half. The decrease in wheat yield will be greater than that of rice yield. In the first half of the 21st century, wheat and rice yields are predicted to decrease at the rates of 1.3%/10 a (P < 0.001) and 0.7%/10 a (P < 0.05), respectively. In the second half of the 21st century, they are predicted to decrease at the rates of 4.9%/10 a (P < 0.001) and 4.4%/10 a (P < 0.05), respectively. The drought stress resulting from climate warming might be the main reason for this projected yield reduction. The greatest decrease in wheat yield (as high as 60%) will occur in the southwest part of the Deccan Plateau, and the greatest decrease in rice yield (as high as 50%) will occur in the northern part of the Gangetic Plain. These findings suggest that food supply in India will face extreme challenges under the future climate change scenarios.