Agricultural yields and rising temperatures

Researchers report links between rising temperatures and global yields of major crops. Humans rely on wheat, rice, maize, and soybeans for two-thirds of their caloric intake. The effect of climate change on the yields of the four crops remains uncertain. Senthold Asseng and colleagues assessed the impact of increasing temperatures on wheat, rice, maize, and soybean yields by performing a meta-analysis of more than 70 studies. The meta-analysis included studies that incorporated analytical methods such as process-based model simulations of yield response to temperature changes at the global and local scale, statistical regression models based on historical weather and yield data, and artificial field warming experiments. All four methods suggest that increasing temperatures are likely to have a negative effect on the global yields of wheat, rice, and maize. Without carbon dioxide fertilization, farming adaptations, or genetic improvement, each degree Celsius increase in global mean temperature is estimated to reduce average global yields of wheat by 6.0%, rice by 3.2%, and maize by 7.4%.  Estimates of soybean yields did not change significantly. The estimated effect of rising temperatures on yield varied greatly across crops and geographical areas, with yields increasing for some crops at some locations. According to the authors, the analyses provide insights into the development of crop-specific and region-specific adaptation strategies for ensuring global food security.

Article #17-01762: "Temperature increase reduces global yields of major crops in four independent estimates," by Chuang Zhao et al.