Mark Gongloff: The world's food supply is under a quadruple attack

Carbon dioxide is plant food, so you might think pumping the atmosphere full of it would be better for plants. The trouble is that CO2 is also the world's most prolific greenhouse gas, trapping heat in a way that creates more problems than it solves for many sensitive plants. This is bad news not only for those plants but for the people who need to eat them.

Heat makes it much harder to effectively grow crops, raise livestock and harvest fish, as detailed in an extensive new report from the United Nations on climate change's threat to food. The hotter the planet gets, the more strain it puts on agriculture. We're at growing risk of seeing a grim example of this in just a matter of months as the world's food supply endures a quadruple attack on its stability.

First, President Donald Trump's trade war hurt U.S. farming by raising prices on fertilizer, tractors and more while cutting off foreign markets for their produce. Then his Iran war made things even worse for farmers all over the world by jacking up the prices of fuel and fertilizer.

Add to this the third element of heat. Many staple crops such as soy, wheat and corn don't do well when temperatures stay above 30 degrees Celsius (86 degrees Fahrenheit) for very long, according to the UN report, produced by its Food and Agriculture Organization and World Meteorological Organization. Livestock suffers in prolonged temperatures above 25C (77F). There has been no sign yet of food crops or animals evolving to better withstand such heat, the report notes.

Marine heat waves also hurt fish and their habitats and food sources, including coral reefs. A heat wave in the Bering Sea in 2018 and 2019 killed off 90% of snow crabs there, leading to the unprecedented halt to Alaskan crab fishing in 2022 and 2023.

Hotter weather also messes with bug populations, weakening pollinators while strengthening pests like the plague of locusts that hit Kyrgyzstan last year. It helps spread diseases. It dries out the soil and worsens droughts. It raises the risk of wildfires. It makes farm workers sick. I could go on.

These disasters often work in tandem, compounding their effects. In the U.S. West and High Plains, one of the hottest winters on record contributed to one of the lowest snowpacks on record. About 70% of the land in both regions is in drought during spring planting season, according to the U.S. Drought Monitor. All of this means less food for humans and livestock. Beef prices, which have already exploded as the U.S. cattle population has dwindled to its lowest level since 1951, have only just begun to rise.

In fact, nearly 77% of the country is abnormally dry, with 63% experiencing full-on drought. Nearly 100% of the Southeast is in drought, including Georgia and northern Florida, which are suffering one of their worst wildfire seasons on record.

A hotter planet, thanks to all the extra CO2 humans have generated, makes hot and dry spells like these much more likely. The 1.4C the planet has already heated since the preindustrial era has gouged global agricultural productivity by 21%, according to the UN report. That's like wasting seven years of productivity gains. It means there's less wiggle room to handle unforeseen disasters such as wars.

"The potential is growing for synchronized production shocks among food-exporting nations due to climate change, heightening concerns about the future of global food availability," the UN report authors wrote.

Which brings us to the fourth horseman of this foodpocalypse: El Niño. This is when an oscillating weather system warms water in the eastern Pacific Ocean, driving up temperatures across the globe. Scientists now expect a new El Niño to form later this year, and there are gathering signs that it could be an unusually strong one.

This could actually be good news for some parts of the U.S. that tend to experience cooler, wetter summers under El Niño. But that's not guaranteed. And it could also be very bad news for the other key agricultural regions of the world that El Niño often leaves hotter and drier.

Consider Brazil. Heat waves and drought in 2023 and 2024 were exacerbated by a relatively strong El Niño, the UN report notes. That reduced soy and corn yields by 10% to 20%. It made pigs skinnier and dairy cows produce less milk. It killed salmon in farms. It subjected more of Brazil's land to wildfires. It exposed agricultural workers to a record number of days in dangerous conditions in some big growing areas.

When the drought broke in Brazil, it did so catastrophically. The heat dome squatting over Brazil in its 2024 autumn contributed to a massive flood in the south that took 183 lives and displaced 600,000 people. It also ruined 2 million tons of unharvested soybeans and damaged 600,000 hectares of grazing pasture for livestock.

El Niño's impacts on local weather aren't uniform or predictable. Its short-term impact on global temperature, however, is. Scientists expect the next one to smash heat records in at least 2027. That heat, along with shortages created by the war, will worsen whatever localized issues farmers experience, making food security a growing problem in India, Africa and other highly populated places.

As the planet warms over the long term, heat's effects on agriculture will worsen exponentially. The extreme-heat intensity we experience at 1.5C of warming will double at 2C and quadruple at 3C, according to the Intergovernmental Panel on Climate Change's Sixth Assessment.

A hotter world in the long run might make it easier to farm in cooler northern locales. But it also risks starvation for the billions living in the swaths of the planet where agriculture will become unviable. Like every other living thing, those people will go where the food is, whether they're welcome or not.

The short-term heat we're about to experience, and the havoc it will wreak on our agriculture, are just a taste of what's to come on our current path. We should take them as a warning. These might be the hottest years on record, but they'll also be some of the coolest years we'll ever enjoy again. Fortunately, there's still time to avoid the worst outcomes by changing our CO2-spewing habits and to prepare our farms, farmers and societies for the disruption already in store.

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This column reflects the personal views of the author and does not necessarily reflect the opinion of the editorial board or Bloomberg LP and its owners.

Mark Gongloff is a Bloomberg Opinion editor and columnist covering climate change. He previously worked for Fortune.com, the Huffington Post and the Wall Street Journal.

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This story was originally published May 1, 2026 at 4:06 AM.