Inside Climate News: Global Warming Means More Insects Threatening Food Crops — A Lot More, Study Warns

Maize weevil. Photo credit: Wikimedia

From Inside Climate News (Bob Berwyn):

Wheat, corn and rice are staple foods for 4 billion people. A new study suggests crop damage from climate change may be far worse than projected as pest risks rise.

Growing swarms of hungrier and hyperactive insects may wipe out big percentages of the world’s three most important grain crops—wheat, corn and rice—even if the world manages to cap global warming at 2 degrees Celsius, the upper-end target of the Paris climate agreement, scientists warn.

The biggest crop losses are expected in temperate areas where global warming will increase both insects’ population growth and their metabolic rates. That includes the major breadbaskets of North America and Europe.

Altogether, the potential scale of the damage is so high, it could threaten global food security, according to research published today in the journal Science.

“We’re turning the dial up in the temperate zones, and insects, for the most part, thrive in a warmer climate,” said co-author and sustainability researcher Josh Tewksbury, director of Future Earth at the University of Colorado. “It gets better and better for them.”

For people accustomed to the pace at which today’s crop-destroying insects migrate, the rapid and widespread changes fueled by global warming may come as a shock. Farmers will need to adapt, Tewksbury said. That could mean overhauling crop rotations, more genetic research and rethinking pesticide use to avoid severe damage.

“Get ready, because the fight is coming to you,” he said.

The researchers project that, globally, crop yield losses for wheat, corn and rice will increase 10 to 25 percent for every degree of global warming. If global temperatures rise 2 degrees Celsius over the 1971-2000 average, they project that the rise in insect pest activity would increase wheat yield losses by a median of 46 percent, corn by 31 percent, and rice by 19 percent.

Those three food crops are staples for about 4 billion people, and account for about 42 percent of direct calories consumed by humans worldwide, according to the UN Food and Agriculture Organization.

University of Washington climate researcher and co-author Curtis Deutsch explained the impact this way:

“Insect pests currently consume the equivalent of 1 out of every 12 loaves of bread (before it ever gets made). By the end of this century, if climate change continues unabated, insects will be eating more than 2 loaves of every 12 that could have been made,” he wrote.

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