Q&A on the Trump EPA’s Effort to Curtail Regulation of Greenhouse Gas Emissions

The Environmental Protection Agency is holding nationalist hearings this week connected its effort to undo the ineligible instauration for its regularisation of greenhouse gases, the heat-trapping gases that origin clime change. In a large argumentation displacement announced successful precocious July, the Trump medication EPA said it would rescind the alleged “endangerment finding,” which allows the bureau to modulate specified emissions, arguing that ineligible and technological developments warrant a reconsideration. At the aforesaid time, the EPA has projected to undo limits connected greenhouse state emissions from vehicles.

The endangerment finding, which the EPA issued successful 2009 nether President Barack Obama, affirmed a well-established technological finding: that existent and aboriginal amounts of greenhouse gases specified arsenic c dioxide and methane successful the ambiance “threaten the nationalist wellness and payment of existent and aboriginal generations.” In a related finding, the Obama EPA asserted that greenhouse state emissions from caller centrifugal vehicles lend to these harms.

The findings required the EPA to enactment limits connected conveyance greenhouse state emissions nether the Clean Air Act, which tasks the bureau with regulating emissions that “cause, oregon lend to, aerial contamination which whitethorn reasonably beryllium anticipated to endanger nationalist wellness oregon welfare.”

The endangerment uncovering besides underlies consequent greenhouse state regulations, including those connected powerfulness plants and lipid and state facilities. In its projected rule connected conveyance emissions, the EPA stated that it is separately reconsidering different greenhouse state emissions standards.

There’s no question successful the climate subject community that human-caused clime alteration threatens nationalist health. The technological ground of the endangerment uncovering was “extensive” successful 2009 and “has been reinforced adjacent further with probe not lone astir the clime system, but besides astir the impacts of clime change,” Noah Diffenbaugh, who studies the impacts of clime alteration astatine Stanford’s Doerr School of Sustainability, said during a July 31 telephone with reporters.

While the EPA’s proposed rule challenges the technological ground of the endangerment finding, claiming “substantial uncertainties,” the agency’s superior arguments for rescinding the uncovering and related conveyance emissions standards are legal.

Below, we reply questions astir the EPA’s connection and what ineligible and clime experts accidental astir it.

Under the national rule-making process, the EPA is seeking nationalist comment connected its projected regularisation done Sept. 22, and nationalist hearings began Aug. 19. The bureau must consider and respond to important nationalist comments earlier issuing a last rule. Legal experts say litigation challenging the regularisation is definite to follow, with the tribunal conflict perchance lasting respective years.

What is the applicable interaction of the EPA’s decision?

The EPA’s projected regularisation takes purpose specifically astatine greenhouse state emissions from caller vehicles. But rescinding the endangerment uncovering has implications for the agency’s quality to modulate greenhouse state emissions successful general.

The EPA has regulated greenhouse state emissions from vehicles opening with exemplary twelvemonth 2012. The latest rules, made nether the Biden administration, were acceptable to statesman to instrumentality effect successful 2027.

The projected regularisation would not affect different tailpipe emissions standards for pollutants too greenhouse gases, nor substance system standards. However, the One Big Beautiful Bill Act, signed into instrumentality July 4, ended penalties for not gathering substance system standards, called Corporate Average Fuel Economy standards. Meanwhile, Trump successful June signed legislature resolutions rescinding California’s waivers to acceptable its ain emissions standards. States person challenged this determination successful court.

The caller regularisation would not straight undo the EPA’s regulations connected sources of greenhouse state emissions beyond vehicles. But if the EPA prevails successful its statement that it lacks the authorization to modulate greenhouse gases, it would supply a ground for the EPA to extremity regularisation of these emissions from different sources.

The EPA nether the Obama and Biden administrations had antecedently attempted to modulate greenhouse state emissions from powerfulness plants. The Trump EPA is separately attempting to undo these regulations, which ne'er went into effect. The endangerment uncovering besides underpins regulations limiting methane emissions from lipid and state facilities, whose compliance deadlines the EPA recently delayed.

In the abbreviated term, the medication “won’t enforce” greenhouse state regulations, Pat Parenteau, an emeritus prof astatine Vermont Law School’s Environmental Law Center, told us.

Jody Freeman, manager of the Environmental and Energy Law Program astatine Harvard Law School and an advisor successful the Obama White House, besides told Heatmap News that “basically, for the remainder of President Trump’s term, you truly shouldn’t expect to spot enforcement oregon enactment connected national clime rules.”

“Could a aboriginal medication reconstruct each of this?” Parenteau said, referring to regularisation of greenhouse gases by the EPA. “The reply determination is yeah, depending connected what the Supreme Court does.”

If the EPA does triumph its main statement that it doesn’t person the authorization to modulate greenhouse state emissions, “that is going to interaction aboriginal administrations,” Parenteau said, perchance requiring them to spell done Congress to found aboriginal limits.

“The ineligible risks of finalizing this connection are considerable,” a trio of attorneys from Harvard Law School’s Environmental & Energy Law Program wrote successful an Aug. 12 ineligible analysis. “However, if EPA proceeds with its superior connection to rescind the Endangerment Finding based connected its caller mentation of the Clean Air Act and courts uphold it, it volition hindrance aboriginal administrations and forestall national regularisation of greenhouse state emissions from the large US sources.”

A afloat triumph for the EPA could unfastened up caller avenues for states to modulate greenhouse state emissions, since states could reason determination were nary longer national standards preempting others.

Further, companies being sued by organizations and states for the harms of emissions from fossil fuels person argued that the EPA’s regulatory authorization preempts these suits. A afloat repeal of the endangerment uncovering could unfastened up companies to liability, Parenteau and different ineligible experts said.

What is EPA’s main ineligible statement for rescinding this finding?

When we reached retired to the EPA astir the projected rule, a spokesperson told america via email: “The Endangerment Finding is the ineligible prerequisite utilized by the Obama and Biden Administrations to modulate emissions from caller centrifugal vehicles and caller centrifugal conveyance engines. Absent this finding, EPA would deficiency statutory authorization nether Section 202(a) of the Clean Air Act (CAA) to prescribe standards for greenhouse state emissions.”

In the proposal, the bureau contends that the Clean Air Act lone applies to section and determination pollutants, not greenhouse state emissions; that the bureau antecedently should person considered the publication of idiosyncratic classes of vehicles and greenhouse gases to planetary clime change; and that the bureau antecedently did not decently see the outgo oregon effectiveness of regulations connected vehicles.

“It’s a mashup,” Parenteau told us. “They’re trying to springiness the courts, and peculiarly the Supreme Court, a smorgasbord of arguments hoping that thing volition stick.”

The EPA led with the statement that greenhouse gases bash not legally suffice arsenic pollutants that endanger well-being, arsenic defined by the Clean Air Act. The EPA said that the applicable conception of the Clean Air Act “does not authorize the EPA to prescribe emanation standards to code planetary clime alteration concerns.”

Instead, the EPA argued, aerial contamination “is champion work successful discourse arsenic referring to section oregon determination vulnerability to unsafe aerial pollution, accordant with our longstanding signifier earlier 2009.” The bureau went connected to say that aerial pollutants governed by the Clean Air Act “are those that origin oregon lend to aerial contamination for which the aerial contamination itself, done section oregon determination vulnerability to humans and the environment, endangers nationalist wellness oregon welfare.” This could see a substance, specified arsenic c monoxide, which is straight harmful to humans, the bureau said, oregon a substance that interacts with sunlight oregon different chemicals to make aerial pollution, specified arsenic successful the lawsuit of the chemicals that interact to origin acerb rain. In contrast, the bureau said, the statement that greenhouse gases endanger nationalist wellness and payment relies connected excessively galore steps to get astatine these harms, and the harms alteration successful severity by region.

The EPA besides argued that, successful issuing a wide endangerment uncovering considering a substance of greenhouse gases, the Obama EPA improperly “severed” the endangerment uncovering from the circumstantial acceptable of vehicles and gases the bureau was trying to regulate. It is not capable to broadly reason that greenhouse gases endanger nationalist health, the EPA argued, saying the Obama medication needed to beryllium endangerment for each greenhouse state and each root of the emissions.

What does the EPA mention for its technological argument?

As a secondary argument, the EPA took aim astatine the technological ground for the endangerment finding, successful galore cases citing a caller report from the Department of Energy that made a series of mendacious and misleading claims to minimize the harms of clime change. The DOE is besides soliciting public comments connected its clime alteration study with Sept. 2 arsenic the deadline.

DOE Secretary Chris Wright hand-picked the authors — 4 scientists and 1 economist with a past of disputing the statement connected clime subject — to form a “Climate Working Group.”

More than a twelve researchers whose findings were cited successful the study person said their work was misused, taken retired of discourse oregon cherry-picked. Scientists are present working connected a much elaborate effect to the 151-page report.

In its projected rule, the EPA argued that the Obama medication had been “unduly pessimistic” astir warming and the wellness impacts of utmost heat. The EPA besides questioned the reliability of anterior conclusions connected topics specified arsenic utmost upwind and oversea level rise, portion arguing that the EPA should person considered benefits of accrued c dioxide. As we person said, clime scientists concluded that the wide ground for the uncovering that greenhouse state emissions endanger quality well-being has successful information strengthened since the archetypal endangerment finding.

In April, the Trump medication dismissed hundreds of experts who had been moving to compile the sixth National Climate Assessment, a papers mandated by Congress, and subsequently deactivated the website that had hosted the anterior reports. Wright astir precocious said the medication was updating these already-published reports. The National Academies of Sciences, Engineering, and Medicine announced connected Aug. 7 that it would behaviour its ain reappraisal focused connected grounds since 2009 “on whether greenhouse state emissions are reasonably anticipated to endanger nationalist wellness and payment successful the U.S.,” with a planned merchandise successful September.

We asked the EPA astir its effect to technological concerns related to the DOE study and whether it would see the NASEM study arsenic it revised its projected rule. “EPA’s connection is ineligible successful nature,” the spokesperson told us, earlier elaborating connected the ineligible argument. “The bureau considered a assortment of sources and accusation successful assessing whether the predictions made, and assumptions used, successful the 2009 Endangerment Finding are close and accordant with the limits connected EPA’s authority” nether the Clean Air Act, the spokesperson said.

“The Climate Working Group and the Energy Department look guardant to engaging with substantive comments pursuing the decision of the 30-day remark period,” a DOE spokesperson told america via email, successful effect to a question astir criticisms from radical whose enactment was cited successful the DOE report.

What bash ineligible experts say?

The existent EPA’s ineligible statement is astatine likelihood with a 2007 Supreme Court ruling successful a lawsuit called Massachusetts v. EPA, a variety of climate lawyers person said. In that case, the justices ruled that greenhouse state emissions qualified arsenic aerial contamination that could beryllium regulated nether the Clean Air Act and that the EPA needed to measure whether the emissions contributed to clime change. The ruling led the EPA to contented the endangerment uncovering and modulate greenhouse state emissions, opening with the conveyance emissions rules.

The existent EPA has argued that previously, the EPA misconstrued the findings of the Supreme Court and that the ruling “did not necessitate the Agency to find that [greenhouse gases] are taxable to regulation” nether the applicable conception of the Clean Air Act.

“This section and determination connection [in the projected rule] is not thing you find successful the Clean Air Act and conflicts with the Act’s intent of protecting the public’s wellness and welfare,” Greg Dotson, who leads the Energy Law and Policy Project astatine the University of Oregon School of Law, told Yale Climate Connections. “Additionally, it runs antagonistic to galore Supreme Court cases implicit the past 20 years.”

The EPA is “counting connected the Supreme Court not applying precedent oregon conscionable overruling it,” Parenteau said. “That’s a large leap. That’s a large ask.”

The Harvard Environmental & Energy Law Program investigation pointed out that the Obama EPA did successful information look astatine impacts of clime alteration successful the U.S. — and that to the grade it looked astatine planetary effects of clime change, it was to recognize however they would impact the well-being of Americans. “EPA misrepresents the 2009 Endangerment Finding erstwhile it asserts that it failed to amusement section endangerment,” the lawyers wrote.

The Harvard investigation besides contended that, contrary to the EPA’s ineligible claim, the Clean Air Act supports “looking astatine sources and emissions successful combination” erstwhile issuing an endangerment finding. Moreover, the investigation said, the EPA did cipher the publication of each conveyance benignant and greenhouse state to emissions successful a supporting papers for the endangerment finding.

“EPA’s intent with this reasoning appears to beryllium to divided US emissions into tiny pieces, fracturing home emissions truthful they look to beryllium a little important stock of planetary emissions,” the investigation said. “This attack would efficaciously prohibit EPA from regulating [greenhouse gas] emissions from the highest-emitting sources successful the US.”

The proscription assemblage contributes 28% of the nation’s greenhouse state emissions, according to the EPA. The U.S. arsenic a state is the second-highest emitter of greenhouse gases wide successful the world, according to the European Commission.

Further, the investigation said, the determination successful Massachusetts v. EPA “makes wide that issuing an endangerment uncovering and processing regulations are 2 chiseled steps,” and it is due to see costs, arsenic the EPA did nether anterior administrations, erstwhile issuing regulations of greenhouse state emissions from circumstantial sources.

The existent EPA said that ineligible developments since Massachusetts v. EPA warrant revisiting the 2009 endangerment finding.

One of these is the overturning of the Chevron doctrine successful 2024. Under this doctrine, courts gave deference to agencies’ interpretations of ambiguous statutes. The EPA argued that the Obama medication had overreached successful claiming the authorization to modulate greenhouse state emissions, saying that “we tin nary longer trust connected statutory soundlessness oregon ambiguity to grow our regulatory power.”

Others argued the overturning of the Chevron doctrine mightiness successful information wounded EPA’s case. Parenteau said the 2024 ruling means the courts bash not request to springiness deference to the agency’s existent mentation of the Clean Air Act.

“They nary longer tin conscionable say, you ought to defer to america nether Chevron” successful interpreting the Clean Air Act, Freeman, the clime lawyer from Harvard, told Heatmap News. Rather, the EPA volition request to person the courts that its mentation of the Clean Air Act is the close one.

The EPA besides cited the 2022 lawsuit West Virginia v. EPA, successful which the Supreme Court ruled that the Obama administration’s Clean Power Plant Plan was invalid. The tribunal cited the major questions doctrine, oregon the thought that an bureau indispensable get wide authorization from Congress earlier asserting a caller regulatory authorization if the contented astatine manus has immense economical and governmental consequences.

The Obama EPA’s determination to modulate greenhouse gases “implicates the ‘major questions doctrine’ due to the fact that it involves questions of large governmental and economical significance, and Congress has not intelligibly fixed EPA authorization to modulate specified pollutants nether the Clean Air Act,” clime lawyer Jeffrey Holmstead, adjunct head of the EPA’s Agency for Air and Radiation nether erstwhile President George W. Bush and subordinate counsel to erstwhile President George H.W. Bush, told E&E News.

But the Harvard ineligible investigation said that the tribunal successful the West Virginia ruling “never questioned EPA’s authorization to modulate greenhouse gases,” but alternatively questioned details of however the bureau was regulating them.

Parenteau argued that the large questions doctrine could wounded the EPA’s argument. He said the EPA’s statement that it does not person the authorization to modulate greenhouse state emissions is itself caller and hugely consequential.

What bash clime scientists say?

The EPA cited the DOE study to minimize the harms of extreme events and sea level rise, and highlight the affirmative impacts of c dioxide connected works growth. It also downplayed evidence of harms from emissions connected agriculture.

As we’ve said, clime scientists person argued that the grounds for the harms of greenhouse state emissions connected nationalist wellness person strengthened implicit time.

In a reappraisal published successful Science successful 2018, researchers wrote that “the lawsuit for endangerment, which was already overwhelming successful 2009, is adjacent much powerfully justified.”

This year, different radical of scientists again reviewed the evidence. The radical successful the aboriginal 2000s had filed an amicus little for Massachusetts v. EPA. “Sixteen years later, the technological grounds supporting the endangerment uncovering is adjacent stronger, with zero countervailing evidence,” the scientists wrote in a commentary published successful June 2025 successful AGU Advances. “Our amicus brief’s predictions of aboriginal clime trends person each travel true, immoderate alarmingly faster than anticipated.” 

The scientists wrote that the “most utmost years” connected grounds for planetary aboveground temperature, planetary water vigor content, arctic oversea crystal retreat, oversea level emergence and water acidity summation person each happened since the 2009 finding.

Further, they said, heat-related deaths are increasing, and woodland and wood fires are becoming much terrible successful Mediterranean climates, starring to fume events. In addition, they said, clime alteration is aiding the dispersed of illness and disrupting agriculture.

Andrew Dessler, a clime idiosyncratic astatine Texas A&M University, has been helping to coordinate scientists’ efforts to respond to the DOE clime report. “The study they produced should beryllium thought of arsenic a instrumentality little from attorneys defending their client, c dioxide,” he wrote in a connection connected societal media. “Their extremity is not to measurement the grounds reasonably but to physique the strongest imaginable lawsuit for CO2’s innocence. This is simply a cardinal departure from the norms of science.”

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The station Q&A connected the Trump EPA’s Effort to Curtail Regulation of Greenhouse Gas Emissions appeared archetypal connected FactCheck.org.