These are the economies that climate change will hit hardest

Unmitigated climate change will make the United States poorer and more unequal, predict researchers. The poorest third of counties could sustain economic damages costing as much as 20 percent of their income if warming proceeds unabated.

States in the South and lower Midwest, which tend to be poor and hot already, will lose the most, with economic opportunity traveling northward and westward. Colder and richer counties along the northern border and in the Rockies could benefit the most as health, agriculture, and energy costs are projected to improve.

“Unmitigated climate change will be very expensive for huge regions of the United States,” says Solomon Hsiang, associate professor of public policy at the University of California, Berkeley. “If we continue on the current path, our analysis indicates it may result in the largest transfer of wealth from the poor to the rich in the country’s history.”

“Increasingly extreme heat will drive up violent crime, slow down workers, amp up air conditioning costs, and threaten people’s lives.”

Researchers used state-of-the-art statistical methods and 116 climate projections to price the impacts of climate change the way the insurance industry or an investor would, comparing risks and rewards.

The team of economists and climate scientists computed real-world costs and benefits: how agriculture, crime, health, energy demand, labor, and coastal communities will be affected by higher temperatures, changing rainfall, rising seas, and intensifying hurricanes.

“In the absence of major efforts to reduce emissions and strengthen resilience, the Gulf Coast will take a massive hit,” says Robert Kopp, professor of Earth and planetary sciences at Rutgers University.

“Its exposure to sea-level rise—made worse by potentially stronger hurricanes—poses a major risk to its communities. Increasingly extreme heat will drive up violent crime, slow down workers, amp up air conditioning costs, and threaten people’s lives.”

If emissions growth is not slowed, then the resulting 6 to 10 degrees Fahrenheit (3 to 5 degrees Celsius) of warming above 19th century levels projected for the last two decades of this century will have costs on par with the Great Recession—except they will not go away afterwards and damages for poor regions will be many times larger.

“The ‘hidden costs’ of carbon dioxide emissions are no longer hidden, since now we can see them clearly in the data,” says Amir Jina, a postdoctoral scholar of economics at the University of Chicago. “The emissions coming out of our cars and power plants are reshaping the American economy. Here in the Midwest, we may see agricultural losses similar to the Dust Bowl of the 1930s.”

Published in Science, the study is the first of its kind to price warming using data and evidence accumulated over decades. From this data, the team estimates that for each 1 degree Fahrenheit (0.55 degrees Celsius) increase in global temperatures, the US economy loses about 0.7 percent of Gross Domestic Product, with each degree of warming costing more than the last.

This metric can help the country manage climate change as it does other systematic economic risks—for example, the way the Federal Reserve uses interest rates to manage the risk of recession.

Researchers used 29,000 simulations of the national economy for the project.

“For the first time in history, we can use these tools to peer ahead into the future,” says James Rising of UC Berkeley. “We are making decisions today about the kinds of lives we and our children want to lead. Had the computing revolution come 20 years later, we wouldn’t be able to see the economic hole we’re digging for ourselves.”

Other coauthors are from Princeton University; the economic analysis firm Rhodium Group; and the risk modeling and data analytics company RMS.