The effects of climate change could drastically reduce US corn crop yields, with a potential drop of up to 40% on previous levels by the decade 2046–55, according to new agricultural risk research.

The 13 states in the US known as the Corn Belt are responsible for 90% of the corn grain and produce in the country and almost 30% of the global corn crop. Using climates projected by four climate models as inputs, simulated yields across the Corn Belt during the decade 2046–2055 were 20 to 40% less than yields simulated during the 1991–2000 decade due to the impact of climate change on weather.

In addition to the reduction in average yield during the 2046-2055 simulation decade, the year-to-year variation in yield increased significantly with climate change, reflecting a reduction in stability of yield and an associated increase in the risk of catastrophic crop losses.

The research by data analytics firm Verisk, in collaboration with David Victor of the Brookings Institution and experts from AXIS Capital, explored how climate change may affect agricultural risk in the US, specifically looking at the impact on corn yield.

Verisk’s extreme event modelling business unit, AIR Worldwide (AIR), conducted the research to isolate effects of variation in weather and climate on corn yield. To better understand and quantify the potential magnitude of climate change impacts on crops, an AIR process-based crop growth and yield model was used to simulate effects of observed past and projected future climate changes on corn yield at high resolution throughout the US Corn Belt, which comprises the states of Iowa, Illinois, Indiana, Kansas, Kentucky, Michigan, Minnesota, Missouri, North Dakota, Nebraska, Ohio, South Dakota, and Wisconsin. Corn was chosen as the study focus because it is the most valuable crop grown in the US and because the country is the world’s largest producer of corn. Many of the lessons learned from this study are pertinent to other major crops grown around the world.

“There is justified concern about effects of recent and future climate changes on agriculture both in the US and across the globe,” said Dr Peter Sousounis, vice president and director of climate change research, AIR Worldwide. “If, or when, climate change brings with it more frequent and/or more extreme unfavourable weather to areas of significant crop production, such as the midwestern United States, the potential for significant crop losses and economic impacts could be heightened. The purpose of this study is to further explore these possibilities for future, more extreme climate changes involving more frequent and more damaging events reducing productivity of major crops.”

Bob Quane, chief underwriting officer at AXIS Insurance, said: “Given how much the industry relies on corn production, it’s important to understand its vulnerabilities to the effects of climate change. Learnings from this research can be applied to the agriculture industry as a whole since any disruptions in this sector are likely to affect other global supply chains – from food and beverage to the production of fibres like cotton. As insurers and reinsurers, we have a critical role in understanding and mitigating risks posed by climate change. This research is vital as we continue to navigate our changing world.”

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