Climate change threatens world food supply. How bad will it be in the US?

The planet’s food system faces growing risks from climate change, a new study published June 18 said. It’s especially worrisome in the United States, where top crop production could drop by as much as 50% by 2100.

The study assessed six staple crops – maize (corn), soybeans, rice, wheat, cassava and sorghum – and found that only rice might avoid substantial losses due to rising temperatures.

“If the climate warms by 3 degrees, that’s basically like everyone on the planet giving up breakfast,” said study co-author Solomon Hsiang of Stanford University in a statement.

Will there still be a Corn Belt?

The projected losses for U.S. agriculture are especially steep, according to the study. “Places in the Midwest that are really well-suited for present day corn and soybean production just get hammered under a high warming future,” said lead study author Andrew Hultgren, of the University of Illinois Urbana-Champaign. “You do start to wonder if the Corn Belt is going to be the Corn Belt in the future.”

Scientists estimated that for every 1.8 degree F increase in temperature above pre-industrial levels, production will decline by 120 calories per person per day, the equivalent of 4.4% of current daily consumption.

This will push up prices and make it harder for people to access food, Hsiang told CNN.

Wheat, soy and corn most affected

Wheat and corn will be among the most impacted crops, the study found.

The study suggested that under a high-emissions scenario, by the end of the century, maize production may decline by up to 40% in the US, Eastern China, Central Asia, Southern Africa, and the Middle East, while wheat loses may range from 15–25% in Europe, Africa, and South America and 30–40% in China, Russia, the USA and Canada.

“This is basically like sending our agricultural profits overseas,” said Hsiang in a statement from Stanford. “We will be sending benefits to producers in Canada, Russia, China. Those are the winners, and we in the U.S. are the losers. The longer we wait to reduce emissions, the more money we lose.”

Steepest losses at the extremes

The steepest losses occur at the extremes of the agricultural economy, according to a statement from Stanford University. That includes modern breadbaskets that now enjoy some of the world’s best growing conditions such as the US, and subsistence farming communities that rely on small harvests of cassava.

In terms of food production capacity from staple crops, the analysis found yield losses may average 41% in the wealthiest regions and 28% in the lowest income regions by 2100.

In the study, scientists concluded further adaptation and the potential expansion of cropland may be needed to ensure food security and mitigate climate impacts.

A favorable climate, Hsiang said, is a big part of what keeps farmland productive across generations. “Farmers know how to maintain the soil, invest in infrastructure, repair the barn,” Hsiang said. “But if you’re letting the climate depreciate, the rest of it is a waste. The land you leave to your kids will be good for something, but not for farming.”

The study was published in the peer-reviewed British journal “Nature.”