Changing Temperatures Are Helping U.S. Corn Production.

• Author: Burrows, Leah
• Position: ECONOMICS

The past 70 years have been good for corn production in the midwestern U.S., with yields increasing fivefold since the 1940s. Much of this improvement has been credited to advances in farming technology, but scientists at Harvard are asking if changes in climate and local temperature may be playing a bigger role than previously thought, as researchers have found that a prolonged growing season due to increased temperatures, combined with the natural cooling effects of large fields of plants, have had a major contribution to improved production in the U.S.

"Our research [published in the Proceedings of the National Academy of Sciences] shows that improvements in crop yield depend, in part, on improvements in climate," says Peter Huybers, professor of earth and planetary sciences. "In this case, changing temperatures have had a beneficial impact on agricultural production, but there is no guarantee that benefit will last as the climate continues to change. Understanding the detailed relationships between climate and crop yield is important as we move towards feeding a growing population on a changing planet."

The researchers modeled the relationship between temperature and crop yield from 1981 to 2017 across the so-called Corn Belt: Illinois, Indiana, Iowa, Kansas, Kentucky, Michigan, Minnesota, Missouri, Nebraska, Ohio, South Dakota, and Wisconsin. They found that, as temperatures increased due to global climate change, planting days got earlier and earlier, shifting by about three days per decade.

"One of farmers' biggest decisions is what they plant and when they plant it. We are seeing that farmers are planting earlier--not only because they have hardier seeds and better planting equipment--but because it's getting warmer sooner," notes first author Ethan Butler, former Harvard graduate student in the Department of Earth and Planetary Sciences who currently is a a postdoctoral research associate in the Department of Forest Resources at the University...