A new study found that staple crops like corn and wheat, which provide a large proportion of the world’s calories and U.S. farmers’ output, will likely see negative impacts from rising global temperatures.
An international group of researchers compiled dozens of studies and found that every time global temperatures go up 1 degree Celsius – not quite 2 degrees Fahrenheit – crop yields fall. On average, the study found a drop of 3 percent for soybeans, 6 percent for wheat and 7 percent for corn.
International agreements, such as the Paris climate accord, hope to limit the global temperature rise to 2 degrees Celsius.
The study focused on the impact of the world’s temperature rising. It did not account for the boost plants can see from higher concentrations of carbon dioxide in the air.
Twenty-nine researchers from across the globe conducted the analysis of more than 70 studies—covering various types of models, approaches and locations across the world—and found that existing research all led, consistently, in one direction.
"What you're seeing here is many different lines of evidence pointing to the same conclusion," said Alexander Ruane, one of the study's co-authors and research scientist at the NASA Goddard Institute for Space Studies in New York.
Researchers used projections to calculate global average temperatures and yields. In some cases, yields went up. Writ large, however, the study found overall declines. Yields for corn and soybeans would decline more in the U.S. than in other parts of the world.
The study, published in the Proceedings of the National Academy of Sciences, suggests any gains American farmers earn by adopting better farming technology will first have to make up for what’s lost to a warmer world.