Global Warming Means More Bugs Destroying Crops

NYT Reports

Ever since humans learned to wrest food from soil, creatures like the corn earworm, the grain weevil and the bean fly have dined on our agricultural bounty. Worldwide, insect pests consume up to 20 percent of the plants that humans grow for food, and that amount will increase as global warming makes bugs hungrier, according to a study published Thursday in the journal Science.

That could encourage farmers to use more pesticides, which could cause further environmental harm, scientists said.

For every degree Celsius (two degrees Fahrenheit) that temperatures rise above the global historical average, the amount of wheat, corn, and rice lost to insects will increase by 10 to 25 percent, the study says. Temperate agricultural regions, like those in the United States and Western Europe, would be particularly hard hit.

The international Paris Agreement is designed to keep warming below two degrees Celsius, but the world’s countries are far off track from meeting that goal.

By eating such a large amount of crops in the field, “insects have consumed something like one out of every eight loaves of bread before it even gets made,” said Curtis Deutsch, a professor of chemical oceanography at the University of Washington and an author of the study. “If we warmed four degrees, which is what climate models typically predict for the end of this century, then that amounts to insects eating two of our eight loaves of bread instead of one.”

Higher temperatures speed many insects’ metabolisms, making them eat more. Their life cycles also get faster, causing them to reproduce more quickly. Both effects would diminish crop yields even as the human population continues to increase, putting additional strains on the global food supply, the study says.

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