Swarms of locusts are best known as a biblical plague — and indeed, for many Americans, they seem like a far-off, even mythical idea. But for farmers in northern Africa, the Middle East, South Asia, and South America, this devastating disaster is a real and growing threat. Locust swarms really do destroy crops, even today, and new research predicts up to a 25% increase in the insects' potential range by the turn of the century, the New York Times reports.

What's happening?

As the Times explains, locusts aren't a problem most of the time. Small populations live in dry desert climates.

However, when a rare, heavy rain falls on the home range of the locusts, the locust eggs in the soil hatch, just as all the seeds in the area start to sprout and take advantage of the water. The young locusts eat up the plants as they mature. When they run out of food, they fly off in swarms to find more, devouring all kinds of crops in the process.

Unfortunately, hot, dry conditions punctuated by heavy rains are exactly what happens on a wide scale when the planet gets hotter. And the planet is getting much hotter overall because of heat-trapping air pollution created by humanity.

Why does it matter if conditions favor locusts?

A team of researchers, including Xiaogang He of the National University of Singapore, wanted to predict how locust swarms would behave in the next several decades, the Times reports. They used computer models to study what might happen depending on how much hotter the world gets by the year 2100.

What they found was that some areas that aren't vulnerable to locust swarms would start experiencing ideal swarm conditions, resulting in anywhere between 5% and 25% more areas being affected. This could cause crop failures and famines.

"Given that these countries often serve as global breadbaskets and are already grappling with climate-driven extremes like droughts, floods, and heat waves, the potential escalation of locust risks in these regions could exacerbate existing challenges," Dr. He told the Times.

They also found that certain areas — like India and Morocco, or Pakistan and Algeria — were likely to be affected at the same time even though they were far apart, compounding food shortages.

What can be done about the locust issue?

Other scientists highlighted one hopeful factor in the fight against locust swarms. Christine N. Meynard of the National Research Institute for Agriculture, Food, and Environment in Montpellier, France, told the Times that in between swarms, global warming will actually make locusts gather in smaller areas, making them easier to control with pesticides.

"If you can focus on fewer areas" for fighting locusts, "it's a lot better," she said.

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