A major new analysis issued Wednesday by the nation’s leading scientific advisory body, the National Academies of Science, Engineering, and Medicine, found that the evidence linking rising emissions to negative human health outcomes is “beyond scientific dispute.”
The timing of the report matters: It comes as the Environmental Protection Agency prepares to enter a new phase in its efforts to reverse a landmark scientific determination that gives the federal government the legal authority regulate greenhouse gas emissions.
The Trump administration wants to roll back the 2009 endangerment finding, which determined that carbon dioxide, methane and other greenhouse gases threaten human health and can be regulated under the Clean Air Act.
Because the endangerment finding forms the basis for so many other rules, some conservatives have seen rolling it back as a way to knock down multiple climate regulations at once. Announcing plans to revoke the finding in July, Lee Zeldin, the E.P.A. administrator, called it “the largest deregulatory action in the history of the United States.”
Put another way: If the endangerment finding is a tablecloth, rules limiting power plant and vehicle emissions are glasses, plates and silverware sitting on top of it. The E.P.A. could gather the corners of the tablecloth and cart everything to the trash in one haul.
One of the Trump administration’s arguments to repeal the endangerment finding amounts to an assertion that the science has changed since 2009, and the evidence no longer supports the conclusions that underpin rules limiting emissions from cars and power plants.
But as Brad Plumer noted, the new National Academies report found the opposite: Evidence that rising greenhouse gas levels can threaten human health has only grown stronger in the years since the original determination.
Why does the E.P.A. regulate greenhouse gases?
In 2007, a Supreme Court ruling found that the Clean Air Act requires the E.P.A. to regulate pollutants that harm human health by warming the planet. The agency issued the endangerment finding that greenhouse gases harmed public health in 2009.
In the months that followed, the agency began issuing new rules that placed limits on greenhouse gas emissions from cars, power plants and other industrial sources.
The Trump administration considered trying to roll back the endangerment finding during his first term, but ultimately did not move forward.
The finding has been challenged in more than 100 lawsuits but has been upheld in appellate courts. As recently as January, business groups that had opposed the rule in the past seemed to have given up. The Chamber of Commerce told the Times that it regarded the finding as “settled law.”
So why is the Trump administration challenging it now?
“As we saw in the 16 years since the endangerment finding was made, many of the extremely pessimistic predictions and assumptions E.P.A. relied upon have not materialized as expected,” said Brigit Hirsch, an agency spokeswoman, in an emailed statement. She added that the agency welcomed public comments on the proposal to repeal the finding through Monday.
Any repeal of the finding would have to survive other legal challenges. And others think there’s a more strategic factor influencing the administration’s moves. “They think they have a good chance of succeeding because the Supreme Court in recent cases has significantly curbed agency authority,” said Sharmila Murthy, a professor of law and public policy at Northeastern University.
Dueling climate science assessments
The E.P.A. justified its plans to roll back the endangerment finding in part by citing a July report commissioned by the Energy Department, which argued that the threat of climate change is overblown. The Energy Department hired five scientists who have questioned the severity of the effects of climate change to put together the report. More than 85 scientists later condemned the report, saying it was rife with errors and misrepresentations.
The National Academies report, by contrast, found that the evidence is stronger than ever that rising emissions pose risks to public health.
Some experts told Plumer that they saw the Trump administration’s attempt to attack the science underlying the endangerment finding as a strategic misstep because it could backfire.
The E.P.A. is required to consider all public comments as it formulates its final determination, and failing to adequately respond to evidence supporting the link between emissions and health effects could open up legal vulnerabilities for the agency.
What if the endangerment finding gets repealed?
If the regulations built on the endangerment finding are rolled back, emissions from power plants and vehicles in the United States are expected to continue to decline, but they’ll do so far more slowly than they would have if limits on emissions had remained in place.
An analysis commissioned by the Natural Resources Defense Council found that emissions from U.S. vehicles are expected to decrease by 40 percent by 2050. But if the E.P.A.’s rules regulating vehicle emissions are struck down, they will decrease by only 10 percent, the report found.
“That’s a huge difference for the largest source of our greenhouse gas emissions here in the U.S.,” said Kathy Harris, the organization’s director of clean vehicles.
The power sector is expected to follow a similar trajectory. Current rules would result in a 41 percent emissions reduction in the power sector by 2032. Without the rules built on the endangerment finding that reduction would be 20 percent.
Our oceans
Corals won’t survive a warmer planet, a new study finds
If global temperatures continue rising, virtually all the corals in the Atlantic Ocean will stop growing and could succumb to erosion by the end of the century, a new study finds.
The analysis of over 400 existing coral reefs across the Atlantic Ocean estimates that more than 70 percent of the region’s reefs will begin dying by 2040 even under optimistic climate warming scenarios.
And if the planet exceeds 2 degrees Celsius of warming above preindustrial temperatures by the end of the century, 99 percent of corals in the region would meet this fate.
The implications are grave. Corals act as the fundamental building blocks of reefs, providing habitat for thousands of species of fish and other marine life. — Sachi Kitajima Mulkey
In one number
An estimated 70,000 deaths per year
If the planet continues to warm at its current rate, exposure to wildfire smoke will kill an estimated 70,000 Americans each year by 2050, according to new research.
The results are some of the strongest evidence yet that climate change endangers people in the United States, said Marshall Burke, an environmental economist at Stanford University who contributed to the study. For Americans, “the impacts are much larger than anything else that has been measured,” Dr. Burke said.
Wildfire smoke, intensified by rising temperatures, is on track to become one of America’s deadliest climate disasters, causing as many as two million deaths over the next three decades, the analysis found. One public health expert called the report a “wake-up call.” — Sachi Kitajima Mulkey and Harry Stevens
In their own words
“When we don’t measure things, it makes it much harder to claim that there is a problem and that the government has some kind of responsibility to help alleviate it.”
That’s from Sarah Pralle, an associate professor of political science at Syracuse University, who spoke to Maxine Joselow for an article about the Trump administration’s moves to stop collecting some forms of climate data.
The administration has moved to stop getting planet-warming emissions data from industrial plants, and various agencies have stoped collecting other types of climate data that have been seen as crucial to understanding a dangerously warming planet.
More climate news from around the web:
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“China’s vast, uncontrolled squid-fishing effort in the unregulated waters off South America is putting marine ecosystems at risk of depletion and leaving crew members vulnerable to physical abuse, overwork and even death,” The Washington Post writes, citing a new report by the Environmental Justice Foundation.
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Carbon dioxide emissions from India’s power sector fell by 1 percent in the first half of 2025 compared with the same period last year, according to an analysis by Carbon Brief. That’s only the second decline in nearly 50 years, the analysis found.
Claire Brown covers climate change for The Times and writes for the Climate Forward newsletter.
The post Trump’s Climate Rollback Takes on a Key Scientific Finding appeared first on New York Times.
