Donald Trump has long railed against emissions-cutting policy as an expensive “hoax” and “scam”. But the climate crisis itself comes with a major price tag for Americans, a new study shows.

Previous research has found that global heating has driven up utility costs, home insurance premiums and healthcare bills. But according to the new study, published in the Proceedings of the National Academy of Sciences journal, it has also slashed US incomes by more than a tenth since 2000 – a severe national economic jolt.

“This study shows that climate change is not just something for the future economy – it is already here,” Derek Lemoine, lead author of the study, told the Guardian.

More on the research and what it means for Americans after this week’s most important reads.

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In focus

Donald Trump speaking at a rally in Oaks, Pennsylvania, during his presidential campaign in October 2024. Photograph: Alex Brandon/AP

Trump has repeatedly spoken out about the costs of tackling the climate crisis. He has dismissed renewables as “too costly”, erroneously called wind the “most expensive energy there is” and decried efforts to combat global heating as an expensive “con job”.

Much of the prevailing narrative around going carbon neutral has also focused on the massive upfront investment needed, and the costs that could be passed on to households and businesses.

But Lemoine’s research shows that leaving global heating unchecked is already proving costly. Rising temperatures have been quietly chipping away at Americans’ earning power for more than two decades – the damage showing up in small, steady losses that add up over time, rather than one dramatic collapse.

To determine the impact of the climate crisis on US incomes, Lemoine used climate models to examine what temperatures would have looked like in a world without human-caused heating, comparing those estimations to actual daily temperature records. Then, he examined US income data from 1969 to 2019, to assess how the changing numbers of hot and cold days affected wealth on a county-wide and national scale.

The results are startling: in a world without global heating, incomes would be on average 12% higher today than they were at the start of the millennium.

While the study did not determine exactly why higher temperatures are associated with lower incomes, previous research can shed light on the potential causes. Hotter temperatures, researchers have long warned, slash crop yields, increase instances of illness and injury, and limit how many hours people can safely work, especially in construction, agriculture and manufacturing.

Crucially, income losses don’t stay local. The US economy is tightly interconnected, so temperature changes in one region can affect prices, trade and demand elsewhere. More heat in places such as California and Arizona, for instance, can shrink crop yields and lead to road closures due to smoke from increased wildfires, making cargo delivery difficult. And those effects can ripple outward, making food more expensive, or materials harder to get hold of, influencing incomes across the country.

When warming is widespread rather than isolated, those effects also become much larger, said Lemoine. “In a connected world, the effects of climate change will spill over man-made borders,” he said.

This shows that solutions are necessary at a national and global level, Lemoine said. “Adapting to climate change involves not just adapting to changes in weather where you live, but also adapting to changes in weather everywhere else in the country and globe.”

Right now, the US appears to be moving in the wrong direction. Just this month, Trump pulled the country out of the UN Framework Convention on Climate Change, the world’s most important climate treaty – another signal of disdain for multilateralism and all attempts to curb emissions. He has also rolled back dozens of environmental rules, and his administration soon plans to scrap a 16-year-old landmark legal finding, which underpins almost all national climate policy and allows the Environmental Protection Agency to limit planet-heating pollution from cars and trucks, power plants and other industrial sources.

Lemoine’s research is just one part of a growing pile of evidence showing that a deregulatory, anti-climate agenda could hurt not just the planet but Americans’ bank balances, as well as delivering even greater losses across the national economy.

Activists are taking note and increasingly attempting to make the link between climate policy and economic problems. In New York City, for instance, Zohran Mamdani, the new mayor, who identifies as a democratic socialist, is perusing affordability-first environmental policies, including making bus travel free to help reduce car use and save commuters money. Seattle’s new mayor, Katie Wilson – also a democratic socialist – says that she will boost social housing while pursuing green retrofits to lower energy bills and slash planet-heating pollution.

Stevie O’Hanlon, co-founder of the youth-led Sunrise Movement, told the Guardian this month: “People increasingly understand how climate and costs of living are tied together.”

Whether Trump will ever reach the same understanding and help the US reverse the damage uncovered by Lemoine’s research remains to be seen.

Read more:

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Economic damage from climate change six times worse than thought – report

Tackling climate crisis will increase economic growth, OECD research finds