Impact of Climate Change on Twenty-First Century Crop Yields in the U.S.

Lillian Petersen

doi:10.3390/cli7030040

Abstract

Crop yields are strongly dependent on the average climate, extreme temperatures, and carbon dioxide concentrations, all of which are projected to increase in the coming century. In this study, a statistical model was created to predict US yields to 2100 for three crops using low and high-emissions future scenarios (RCP 4.5 and 8.5). The model is based on linear regressions between historical crop yields and daily weather observations since 1970 for every county in the US. Yields were found to be most strongly dependent on heat waves, summer average temperatures, and killing degree days; these relationships were hence used to predict future yields. The model shows that warming temperatures will significantly decrease corn and soybean yields, but will not have as strong of an influence on rice. Before accounting for CO2 fertilization, crops in the high-emissions scenario are predicted to produce 77%, 85%, and 96% of their expected yield without climate change for corn, soybeans, and rice, respectively. When a simple CO2 fertilization factor is included, corn, a C4 plant, increases slightly, while the yields of the C3 plants (soybeans and rice) are actually predicted to increase compared to today’s yields. This study exhibits the wide range of possible impacts of climate change on crop yields in the coming century, and emphasizes the need for field research on the combined effects of CO2 fertilization and heat extremes.

Highlights

On 8 October 2018, the Intergovernmental Panel on Climate Change (IPCC) released a new report titled Global Warming of 1.5 ◦ C, which concludes that drastic action must be taken to limit global temperature rise and avoid serious negative impacts
Corn and soybeans observe large geographical distributions in the eastern and central US, while rice is mostly grown along the Mississippi River
Spatial variations of slopes and correlations can be examined for corn and soybeans

Summary

Introduction

On 8 October 2018, the Intergovernmental Panel on Climate Change (IPCC) released a new report titled Global Warming of 1.5 ◦ C, which concludes that drastic action must be taken to limit global temperature rise and avoid serious negative impacts. It finds that natural, managed and human systems have a high risk of permanent damage as the climate warms. Extreme weather events will occur more often, including droughts, floods, coastal storms, and heat waves, increasing mortality and property damage. As warmer temperatures combine with more extreme weather events, cereal yields will decrease [1,2]. If we fail to limit fossil fuel combustion, all of the effects will increase [3]

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