The Brief

The Trump administration announced its plan today to overturn a key 2009 Environmental Protection Agency finding that underpins much of the federal government's actions to rein in climate change.

The EPA argues it doesn't have the legal authority to regulate greenhouse gases. The agency proposes to undo the government's "endangerment finding," a determination that pollutants from developing and burning fossil fuels, such as methane and carbon dioxide, can be regulated under the Clean Air Act.

"With this proposal, the Trump EPA is proposing to end sixteen years of uncertainty for automakers and American consumers," EPA administrator Lee Zeldin said in an agency press release.

The EPA also plans to eliminate rules to reduce climate pollution from cars and trucks. Transportation is the largest source of direct greenhouse gas emissions in the United States.

The announcement, made by Zeldin at a car dealership in Indiana, is for now only a proposal. Climate advocates vow to challenge it, first in comments during the process to finalize the proposed rule on the endangerment finding and then in court, if necessary.

"As Americans reel from deadly floods and heat waves, the Trump administration is trying to argue that the emissions turbocharging these disasters are not a threat," said Christy Goldfuss, executive director of Natural Resources Defense Council. "It boggles the mind and endangers the nation's safety and welfare."

The administration's effort comes in the wake of the hottest year humans have ever recorded on Earth, dangerous flooding in communities across the U.S., climate-fueled wildfires that destroyed thousands of homes in Los Angeles and hotter ocean temperatures that made Hurricane Helene stronger and more likely to cause damage inland.

If the decision is upheld, it would speed President Trump's efforts to end former President Biden's ambitious climate agenda, and make it more difficult for future administrations to limit the human-caused greenhouse gas pollution that's heating the planet.

A cornerstone of U.S. climate action

In 2007 the Supreme Court found in Massachusetts v. EPA that the agency is required to regulate carbon dioxide and other greenhouse gas emissions under the Clean Air Act. Then in 2009 the EPA, during the Obama administration, declared that greenhouse gases in the atmosphere were a hazard to people.

The endangerment finding is the basis for rules regulating climate pollution from coal and gas-fired power plants, car and truck exhaust, and methane from the oil and gas industry.

The EPA has repeatedly reaffirmed the 2009 endangerment finding. In 2022 Congress included language in the climate-focused Inflation Reduction Act that labels greenhouse gases as pollutants under the Clean Air Act. That makes abandoning the finding more difficult. Still, President Trump has made doing that a priority.

On the first day of his second term, Trump signed an executive order asking the EPA administrator to submit recommendations "on the legality and continuing applicability" of the endangerment finding. That echoes recommendations laid out in the Heritage Foundation's Project 2025, a conservative plan that aims to limit the government's ability to regulate climate pollution.

Zeldin first announced the EPA's intention to eliminate the endangerment finding in March, in what the agency called the "most consequential day of deregulation in U.S. history."

"We are driving a dagger straight into the heart of the climate change religion to drive down cost of living for American families, unleash American energy, bring auto jobs back to the U.S. and more," Zeldin said in a news release at the time.

The Trump administration's position

The Trump administration argues the EPA, under then-President Barack Obama, established the endangerment finding in "a flawed and unorthodox way" and "did not stick to the letter of the Clean Air Act."

In seeking to reverse the endangerment finding, the Trump EPA is making a legal argument that previous administrators overstepped their legal authority and "imposed trillions of dollars of costs on Americans." The agency repeats past Republican arguments that the 2007 Massachusetts v. EPA decision "explicitly did not hold that EPA was required to regulate these emissions from these sources." And the EPA argues that more recent Supreme Court decisions raise further questions about the legality of the 2009 endangerment finding.

The U.S. is the largest historical emitter of man-made climate pollution and, under the 2015 Paris climate agreement, has agreed to contribute to the global effort to reduce emissions and limit warming. Trump has signed a directive to have the U.S. withdraw from that agreement.

"This cynical one-two punch allows Trump's Flat Earth EPA to slam the brakes on reducing auto pollution and ignore urgent warnings from the world's leading scientists about the need for climate action," wrote Dan Becker of the Center for Biological Diversity, in a statement to NPR. "By revoking this key scientific finding Trump is putting fealty to Big Oil over sound science and people's health."

In 2024, Trump suggested oil executives should raise $1 billion for his presidential bid because he would roll back environmental rules.

"NRDC's lawyers and scientists are not going to let that happen without a fight. If EPA finalizes this illegal and cynical approach, we will see them in court," Goldfuss wrote in a statement.

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Four million acres of California’s wildest backcountry could soon be opened to paving roads and logging.

The Trump administration announced last week that it’s pushing forward with a proposal to scrap a 2001 rule that blocks logging, road building and other construction in parts of national forests. The administration argues repealing the so-called “roadless rule” is key to managing vegetation to better prevent wildfires on public lands.

Environmental advocates and other groups worry rescinding the rule would harm pristine habitat and the wildlife it supports, and open up more public land to industrial activities and human access that can cause more wildfires.

And locals are worried about losing access to some of the last protected natural lands in the region.

“What we're dealing with here in the roadless rule is the protection of the backcountry,” said David Browning, president of the Orange County Mountain Bike Association, “where you can actually go out and be having an experience where you don't hear traffic, where you don't see buildings, where you actually remember what it was like before all of us got here.”

In Southern California, large swaths of the Los Padres, Angeles, San Bernardino and Cleveland national forests would lose protections.

Browning, who spoke with All Things Considered host Julia Paskin on Monday, said he’s particularly concerned about the Santa Ana Mountains, where much of Orange County’s backcountry biking trails exist within a roadless area that could be opened to construction.

“Our mission is to protect and expand trail access, and so our entire agenda is to make sure that in a highly populated county, like Orange, that we have available the outdoors to be able to go and enjoy,” he said.

Browning takes issue with the wildfire argument — he pointed to the 2024 Airport Fire, which was sparked when heavy equipment operated by Orange County employees struck a rock. They were moving large boulders that day to, in part, block vehicles from getting into a dry brush area and potentially starting a fire. Browning said the “roadless rule” prevents such access that could increase the risk of fire. A recent peer-reviewed study supports that, finding that although roads are important for managing a fire once it ignites, they’re also more likely to be a place where a fire starts.

Though addressing wildfires and protecting public lands have become heavily politicized under the Trump administration, Browning thinks most locals probably aren’t as divided.

“ I don't think this is a party issue,” he said. “We want to hold onto the outdoors and protect them as best we can.”

There unfortunately isn’t much respite in sight for heat-weary Southern Californians.

Forecasters say this week’s heat wave is likely to be the hottest so far this summer. Extreme heat warnings will be in effect from the National Weather Service for almost the entire region from Tuesday morning through Friday evening.

Temperatures will peak between Tuesday and Thursday.

Highs in downtown Los Angeles are expected to reach around 100 degrees, and the warmest inland valleys will get up to 112. L.A. County beaches will hit the high 80s.

Forecasters have also issued Red Flag Warnings for the interior mountains and foothills of Los Angeles, Ventura and Santa Barbara counties. Gusty winds and low humidity at higher elevations mean fires could spark and spread quickly.

At lower elevations, humidity continues to make the heat feel more sweltering and make it harder to cool down, especially at night. Nighttime temperatures will only get down to the 70s in most places, including along the coast.

A slight cooldown is expected this weekend, though forecasters say temperatures will stay above normal into next week.

The extreme heat this week poses an especially high risk of heat-related illness for people over 65, young children, people who work or spend a lot of time outside and those without access to air conditioning.

Driving the heat

Several factors are behind this week’s heat wave, many of which have also been behind the rest of this summer’s consistently hot weather.

The main driver is a high pressure air system hovering over the southwestern U.S., trapping warm air, compressing it and warming it further, and blocking cooler air from entering the region.

Offshore winds are also pushing warm inland air toward the coast, preventing cooler onshore winds from blowing inland.

“That blocks our natural air conditioning off the ocean from coming in as early as it normally does,” said Weather Service meteorologist Mike Wofford. “So as long as that cool air stays offshore, it heats up on land.”

The offshore winds are not strong enough, however, to significantly dry out the air in the L.A. Basin and cut down on the humidity.

“That's probably going to be around for the whole summer because you’ve got all this warm ocean water that's feeding into that,” Wofford said.

Warmer seawater evaporates faster, adding to moisture in the air and increasing humidity across the region, especially along the coasts.

Air quality warnings

Along with the heat this week, many Southern Californians also have smog to worry about.

The South Coast Air Quality Management District issued an ozone advisory on Monday for inland areas of Los Angeles and Orange counties, much of Riverside County and parts of San Bernardino County. It will remain in effect through Friday evening.

The multi-day smog event is in part driven by the heatwave.

Officials say ozone pollution may reach unhealthy levels or higher in the Santa Clarita Valley, parts of the San Gabriel and San Bernardino valleys, and portions of the San Bernardino Mountains.

Under unhealthy levels, it’s possible for anyone to experience adverse health effects like difficulty breathing and throat irritation. Sensitive populations could experience more serious effects.

Levels are expected to be unhealthy for sensitive groups in the San Fernando Valley, Perris Valley, Mission Viejo, Lake Elsinore, Corona, Hemet, Riverside and Pasadena.

Officials advise certain vulnerable groups — including people with heart or lung disease, those with asthma, pregnant women, children and people over 65 — to limit their time outdoors.

Officials predict that ozone levels will be lower along the coast.