While extreme heat has long been recognized as a lethal health hazard that preys upon preexisting patterns of inequality and vulnerability, experts are trying to alert the public to another deadly dimension of the climate emergency: Soaring temperatures jeopardize the stability of the world's agricultural land and its oceans, putting potentially billions of people at heightened risk of hunger and conflict.
"Our food system is global," John Marsham, a professor of atmospheric science at the University of Leeds in England, toldThe Guardian. "There are growing risks of simultaneous major crop losses in different regions in the world, which will really affect food availability and prices. This is not what we're seeing right now, but in the coming decades that's one of the things I'm really scared of."
"As a human being, if you're wealthy enough, you can get inside and put the air conditioning on," said Marsham. "But natural ecosystems and farmed ecosystems can't do that."
Extreme heat and droughts are already having a discernibly negative impact on food production. In 2022, the heatwaves that killed more than 61,000 people in Europe also reduced the continent's agricultural output, hastening a decadeslong trend. Also last year, a historic drought in China resulted in crop losses, while a heatwave in India undermined wheat exports. In addition, famine is looming in the Horn of Africa due in large part to an ongoing climate-intensified drought.
These catastrophes—combined with Russia's war on Ukraine, which has damaged one of the world's key breadbaskets—have contributed to a yearslong spike in global hunger.
As a result of unmitigated greenhouse gas pollution, heatwaves are projected to become increasingly common, longer-lasting, and more severe in the coming years—providing even less time for recovery between events and leading to greater cumulative harm.
"People are generally isolated from the effects of the weather on which we all depend. We go to shops to buy food—we don't grow it ourselves," Marsham continued. "But if you talk to farmers anywhere in the world, they are extremely aware of what the weather is doing, and the impacts on their farming."
Meanwhile, as carbon dioxide and methane emissions continue to propel global warming, oceans absorb an estimated 90% of the excess heat trapped in the planet's atmosphere. This is accelerating ocean warming at a ferocious pace, especially in 2023, frightening experts in the field.
Not only do higher ocean temperatures put millions of people at risk of accelerated sea-level rise and turbocharged extreme weather, but they also disrupt the marine ecosystems that supply one-fifth of the world's protein. Just two years ago, a heatwave in British Columbia killed more than 1 billion intertidal animals.
Daniela Schmidt, a professor of earth sciences at the University of Bristol in England, told The Guardian on Friday: "We often think about impacts on ecosystems on land because it's easy to see—the plants wilt and animals get too hot. But people generally don't think about marine heatwaves. That's what really worries me—that unseen, silent dying."
As the newspaper noted:
Some of the most vulnerable ecosystems are the ones used to having a stable temperature year-round, such as species in the tropical oceans. Warming of 2°C is expected to essentially wipe out tropical coral reefs. They have the highest biodiversity of any ecosystem globally, and support more than 500 million people worldwide, most of whom are in poor countries.
"I've got young kids," Marsham said. "Whenever you watch Finding Nemo or read a book about coral reefs, you can't help but feel that, on some level, you're selling them a lie. Unless we act fast, those systems are going to disappear. Some people might not care about coral reefs, but there's no part of the globe that is immune to the impacts of climate change."
Schmidt added: "Not everything has to have a financial value. You need plants for every breath you take. It's the oxygen you breathe—we tend to forget that."
Friday's warnings echo recent peer-reviewed research about the specter of concurrent crop losses in the world's top food-growing zones due to climate breakdown. According to a paper published in Nature Communications earlier this month, most existing climate models tend to underestimate the mortal danger posed by "simultaneous harvest failures across major crop-producing regions."
It is far from the only study published recently to sound the alarm about the relationship between heatwaves and hunger. Research released in June assessed "a worst-case scenario in which extreme weather hits two breadbasket regions in the same year," as NBC Newsreported at the time.
Another paper from last August noted that "extreme heat not only damages agricultural yields and leads to supply drops and food insecurity in the long-term but also affects people's short-term ability to generate income from labor and purchase food."
Scientists said Thursday that newly arrived El Niño conditions are projected to make 2024 even hotter than this year.
"Without global action to address climate change, we will see unprecedented levels of hunger," the U.K. arm of the United Nations World Food Program tweeted Friday, noting The Guardian's report.
Despite mounting evidence of the climate emergency's disastrous consequences, fossil fuel giants—which raked in hundreds of billions of dollars in profits last year after knowingly suppressing warnings about the climate crisis for decades—plan to expand drilling operations in the coming years. Policymakers have shown little willingness to stop them, as COP27 ended in November with no commitment to phase out coal, oil, and gas.
Referring to the study published earlier this month in Nature Communications, journalist George Monbiot argued last week that "the struggle to avert systemic failure is the struggle between democracy and plutocracy."
"It always has been," he added, "but the stakes are now higher than ever."
