A combination of ozone and higher temperatures could lead to a reduction in crop yields.
A new study conducted by researchers at the Massachusetts Institute of Technology showed how these factors can affect food supply. Past research has largely ignored the interactions between warming temperatures and air pollution.
The study focused on rice, wheat, corn, and soy, which make up about half of the calories consumed by humans across the globe. Different crops are believed to be more sensitive to different factors; wheat is more susceptible to ozone damage while corn suffers more from heat. The work is described in the journal Nature Climate Change.
The effects of these factors are predicted to vary greatly by region. In the United States tougher air quality regulations can lead to a decline in ozone pollution, limiting its effects on crops. In other regions the outcome will depend on their air pollution policies and cleanup.
Warming is predicted to reduce crop yields by 10 percent across the world in the year 2050, but air pollution control could help lower these numbers. The world is expected to need 50 percent more food by 2050, so the finding is troubling.
Heat and pollution can both damage crops individually, but their interactions can be harmful as well. Warmer temperatures increase the production of ozone from reactions between volatile organic compounds and nitrogen oxides in sunlight. About 46 percent of damage to soybean crops that was once believed to caused by heat is actually a result of this increase in ozone.
"[Agricultural production is] very sensitive to ozone pollution," said Colette Heald, an associate professor of civil and environmental engineering (CEE) at MIT, adding that these findings "show how important it is to think about the agricultural implications of air-quality regulations. Ozone is something that we understand the causes of, and the steps that need to be taken to improve air quality."
