Clean Air—and Science—is Under Attack

I live in the pristine mountains of Vermont. As a distance runner and someone who loves the outdoors, good air quality is something I’ve always taken for granted. Until recently. Over the last few years, increased heat and resulting dry conditions have caused unprecedented wildfires in nearby Canada that have sent smoke and harmful pollution into our air.

As such, the number unhealthy air days has increased and Vermont’s queen city, Burlington, has dropped off the list of cities with some of the cleanest air. For a growing number of warm summer days, outside activity has become dangerous for sensitive groups and, on bad days, for everyone. It has also increased visible haze, veiling the scenic backdrops Vermonters love.

Air pollution is not the only recent climate change related risk threatening lives and health. The region now sees 50% more precipitation than it did in 1995. With steep hills and narrow valleys, this means flooding. Hurricane Irene devastated countless towns in 2011. A 2023 flood placed the state’s capital under water and 2024 flooding almost submerged the capital again and washed away buildings and homes in a nearby village. Based on disaster declarations, Washington County—home to Montpelier—is now tied for the second-most disaster-prone county in the nation.

My little city of Montpelier, Vermont is not unique. Unprecedented floods, fires, and heat waves have devastated communities from Asheville to central Texas to Los Angeles. All of which makes it a puzzling time for the entity entrusted to protect the environment and public health—the Environmental Protection Agency—to decide that the emissions that cause climate change are no longer something it needs to concern itself with.

The Endangerment Finding

In 2007, the U.S. Supreme Court ruled in Massachusetts v. EPA, 549 U.S. 497 (2007) that the term “air pollutant” in the federal Clean Air Act (CAA) encompasses greenhouse gases that cause warming such as carbon dioxide and methane. In the case, the Court rejected an argument by the EPA that the CAA did not authorize it to regulate gases that cause climate change.

Instead, in a 5-4 decision, the Court concluded that it was “unambiguous” that “greenhouse gases fit well within the Clean Air Act’s capacious definition of ‘air pollutant.'” Since the Court concluded that the EPA had authority to regulate GHG emissions, the EPA was obligated under the Act to determine whether GHGs “cause, or contribute to, air pollution which may reasonably be anticipated to endanger public health and welfare.”

In 2009, after an exhaustive review of the overwhelming science, the EPA concluded that six GHGs endanger public health and public welfare. It also concluded that the GHG emission from new motor vehicles “cause or contribute” to climate change. When this finding was challenged, a federal appeals court found that the EPA’s conclusions were “supported by substantial evidence.”

Since 2009, the endangerment finding has been the linchpin of federal efforts to reduce harmful GHG emissions across multiple sectors, primarily the transportation and power sectors where most of the U.S. GHG emissions occur. Both the first Trump Administration and the Biden Administration rejected petitions to overturn the finding. Moreover, industry—even the fossil fuel industry—has generally come to accept the finding.

The EPA Wants to Rescind the Finding

Despite the overwhelming science, legal directive from the Supreme Court, and acceptance by industry, the second Trump Administration is aggressively moving to rescind this scientifically supported finding, mocking it as “the holy grail of the climate change religion.” It is also proposing to repeal all GHG emission standards for vehicles established since the finding issued in 2009.

Its rationales are both expected and surprising. Primarily, the EPA argues that the Clean Air Act does not grant it the authority to regulate pollutants unless they contribute to local or regional exposures. It is also contending that it cannot regulate pollution where the link between the pollution emitted and the harms caused appears attenuated—in essence arguing that because the link between emissions from traffic and the harms of climate change are not direct because other factors and emissions lead to climate change as well, EPA has no duty to regulate these emissions.

As the proposal puts it, “emissions from new motor vehicles and new motor vehicle engines in the United States do not have a sufficiently close connection to the adverse impacts identified in the Endangerment Finding to fit within the legal meaning of ‘cause’ or ‘contribute.’” This argument, some legal experts have alleged, is effectively a recycling of the failed argument that the EPA lost in Massachusetts v. EPA.

Given that many legal scholars feel that the EPA is on thin legal ground, it has concocted a stew of other rationales, likely hoping at least one will find a receptive ear with the courts.

These arguments include: climate change science is uncertain (which a recently-released Department of Energy report tries to bolster); there was not direction from Congress to regulate GHG emissions; technology does not exist that would meaningfully address the impacts of GHG emissions; eliminating emissions from motor vehicles would be futile in meaningfully addressing climate change; and that more expensive new vehicles would result in keeping older, higher emitting cars on the road because people would be deterred from buying new cars due to higher prices.

What Can We Do?

Assuming the rescission is finalized, it will almost certainly face stiff and swift challenges in court. As indicated above, this move by the EPA is on tenuous legal and scientific grounds and the agency must convince judges that its 180 turn after 16 plus years of increasingly strong science and notable harms is not arbitrary.

If the EPA is successful in fending off challenges—and it bears noting that of the nine justices who decided Massachusetts v. EPA, the only three still on the Court were in the dissent—the overturning of the endangerment finding would undo GHG vehicle emissions standards and many, if not most, other the EPA actions to curb harmful GHG emissions.

It will also cause some immediate uncertainty—which may be more difficult for industry to navigate than a predictable set of federal regulations. In the 2011 case AEP v. Connecticut, the Supreme Court relied on the EPA’s authority to regulate GHS to find states were precluded from holding emitters liable under state common law for environmental harms from climate change.

Overturning that authority could expose emitters to potentially steep liability under state common law. It may also open the door for states like California to directly regulate tailpipe and other emissions, which could create a patchwork of regulations for industry to keep pace with.

We cannot afford the confusion or the delay. Each fraction of a degree of warming poses risks to people, communities, and wildlife. It is paramount that Congress not leave this important issue to the courts and vacillate the EPA regimes. It is past time for clear direction from Congress to ensure a just, clean, and prosperous transition to a clean energy future that accounts for carbon pollution and protects us from its growing harms.

Your voice is important in our fight to protect human health, the health of wildlife, and our environment. The EPA is required to accept comments on their proposal from the public. Take action now and tell the EPA they cannot rescind the Endangerment Finding.