The central trend in crop yields under climate change in China: A systematic review.

Evidence from numerous studies has confirmed the impact of climate change on crop yields in China since the IPCC AR4. However, the results from different studies can differ widely due to differences in crops, regions, scenarios, and analytical approaches. We assessed the projected impacts of climate change on the yield of major crops (wheat, rice, and maize) in China using a systematic review at the national and subregional levels based on a data set of 667 published simulations. The results show that (1) the impact of climate change on crop yields was mainly reflected in temperature increases, with an average yield loss of 2.58% per °C at the national level. Subregional yield changes ranged from -12.70% to -2.57% per °C, with crop yields being more vulnerable in Northeast China and Northwest China than in other subregions. (2) The yields of crop samples that included CO2 effects were 9.23% higher than the yields of those without CO2 effects. (3) Evidence of the impacts of precipitation on crop yield was robust for Northeast China, Northwest China and North China and was absent or contradictory for the other subregions. (4) Of the three different crops, the response of wheat yields to warming was the most evident, especially in Northwest China, followed by that of maize yields in Northeast China. The negative effects of temperature increases on rice yields were significant at the national level but not at the subregional level. This study synthesized the results from all available studies in a systematic and unbiased manner and provided a robust assessment of the likely impacts of climate change on crop yields.