Uncertainty in Assessing Temperature Impact on U.S. Maize Yield Under Global Warming: The Role of Compounding Precipitation Effect

Abstract

AbstractHigh temperature alone would lead to a well‐understood loss of crop yields, but the compounding effects by other global change factors are much less well understood and can either amplify or reduce temperature‐driven yield change. Analysis focusing on U.S. maize yield shows that the concurrent changes in precipitation have nonnegligible influence on temperature‐yield relations. For the country as a whole, ~27% of the observed strength of temperature‐yield relation relates to the compounding precipitation effects. Further analysis shows that precipitation exerted the compounding effects mainly through its direct influence on yields rather than indirectly from its feedback to temperature. Under 2 and 1.5°C global warming, maize yield for the country as a whole is projected to decrease by ‐13.53 to ‐14.37% and ‐9.02 to ‐9.29%, respectively, with the magnitude of change depending on the climate model. Around 30% of the benefit by constraining global warming to 1.5°C would be contributed by the compounding precipitation effects, pointing to the important role of precipitation in regulating the impacts of temperature rise on yields. The results can greatly improve our understanding and interpretation of the important but uncertain temperature‐yield relations.