Future climate impacts on global agricultural yields over the 21st century
S. T. Waldhoff, I. Sue Wing, J. Edmonds, G. Leng, and X. Zhang
Environmental Research Letters (10 August 2020)
Analyses of the future impacts of changing crop yields on agricultural production, prices, food security, and GDP growth using Integrated Assessment models require country-level yield shocks due to changing weather conditions, for a wide range of crops and warming scenarios. We characterize impacts of different climate futures on crop yields for individual countries and years. We use historical crop yield and weather data to empirically estimate annual crop yield responses to temperature and precipitation, constructing reduced-form statistical models that are then coupled with Earth System Model (ESM) outputs for the same variables to project future yields. Our main result is a panel of annual shocks to yields of 12 crops (cassava, cotton, maize, potatoes, rice, sorghum, soybean, sugar beet, sugarcane, sunflower, and winter and spring wheat) for 58-136 countries, depending on the crop, through 2099, under moderate and vigorous warming scenarios. We find that global yield impacts by century’s end (2086-2095) are -2%, -19%, -14%, and -1%, without the CO2 fertilization effect (CFE), for maize, rice, soybean, and wheat, respectively, with similar global values with CFE. However, the global and decadal averages mask regional and year-to-year differences that may have large economic consequences, which IAMs could more fully address by representing agricultural yield impacts through the parameters supplied by our study.