City Files Three Comments Letters, Amicus Brief Opposing EPA’s Proposal to Reverse Landmark 2009 “Endangerment Finding” That Will Roll Back Federal Motor Vehicle Emission Standards Protecting Health and Safety of Americans
Increasing Risk for Natural Disasters Will Threaten Public Health, Safety, Local Economies
Announcement Comes at the Start of “Climate Week NYC”
The City of New York today announced that — as part of a coalition of dozens of cities, counties, and states from across the nation — it has filed three comment letters opposing the U.S. Environmental Protection Agency’s (EPA) proposed reversal of its 2009 “Endangerment Finding.” The landmark 2009 finding holds that greenhouse gas emissions — including those from motor vehicles — drive climate change and endanger public health and welfare. The new proposal — issued on August 1, 2025 — would deny the EPA’s authority to regulate harmful air pollution that contributes to climate change, harms public health, and would eliminate all existing EPA vehicle emission standards.
Additionally, earlier this month, the City of New York and a coalition of 19 attorneys general filed an amicus brief in the U.S. District Court for the District of Massachusetts in Environmental Defense Fund v. Wright, supporting the plaintiffs in a case challenging the authority of the Climate Working Group, convened by the U.S. Department of Energy in violation of Federal Advisory Committee Act requirements, to prepare a report that purports to undermine the scientific consensus on climate change.
This announcement builds on the work the Adams administration has done to address climate change and comes at the start of “Climate Week NYC,” the world’s biggest climate event of its kind. In 2024, Mayor Adams introduced the city’s first-ever climate budgeting publication through the city’s Fiscal Year 2025 Executive Budget. Climate budgeting is a process that incorporates science-based climate considerations into the city’s budget decision-making process by evaluating how actions and spending today contribute to meeting longer-term climate targets and needs. New York City is the first big city in the United States to adopt climate budgeting, joining other global cities, such as London, Oslo, and Mumbai, to utilize the process.
“New York City is no stranger to the devastating effects of natural disasters. With more extreme weather events hitting the five boroughs more often, for our safety and to protect our economy, we must be prepared for the effects of climate change, including by putting in place stronger federal regulations of greenhouse gases,” said Mayor Adams. “Attempts to undermine this scientific consensus should not be the basis for undoing important regulations that mitigate future environmental damage that threatens lives, brings harm to our communities, and hampers our economies. We are proud to stand with our partners from across the nation in taking multiple actions supporting long-held scientific findings that protect against environmental disasters in our communities.”
“More than a decade ago, the EPA formally determined that greenhouse gases threaten the public health and welfare of the American people, and that emissions from motor vehicles and engines contribute to the greenhouse gas pollution that threatens public health and welfare,” said New York City Corporation Counsel Muriel Goode-Trufant. “Now, over the span of a few months, the U.S. Department of Energy and the EPA have sought to manufacture a basis to reject this overwhelming scientific consensus, endangering all Americans and all New Yorkers.”
The 2009 Endangerment Finding was the direct result of the landmark 2007 U.S. Supreme Court opinion in Massachusetts v. EPA, which confirmed the EPA’s authority under the Clean Air Act to regulate greenhouse gas emissions that threaten public health and welfare. In direct response to that opinion, and after more than two years of scientific review, the EPA determined, in 2009, that greenhouse gas emissions from motor vehicles contribute to air pollution that harm public health and welfare.
2009 Endangerment Finding Comment Letter
In their letter submitted to the EPA today, the coalition argues that rescinding the 2009 Endangerment Finding would violate settled law, Supreme Court precedent, and scientific consensus, endangering the lives of hundreds of millions of Americans, particularly those in communities disproportionately impacted by environmental harms.
Scientific research has proven that every region of the country is experiencing harms of climate change and motor vehicle pollution, including changes in temperature, precipitation, and sea level rise. Extreme summer heat — driven by climate change — is leading to increased rates of heat-related illnesses and deaths, particularly among vulnerable populations like children, the elderly, low-income individuals, and workers. Increasing rates of natural disasters — like wildfires, hurricanes, flooding, and droughts — not only have a devastating effect on public health and safety, but on state and local economies as well.
Climate change poses existential risks to New Yorkers’ health and safety. Sea level rise in New York City is putting communities and infrastructure at risk of regular flooding. Extreme weather events — such as Superstorm Sandy in 2012 and Hurricane Ida in 2021 — can result in injury and loss of life due to exposure, interrupted utility service, or lack of access to emergency services. Additionally, warming temperatures exacerbate or introduce health problems. On average, more than 500 New Yorkers die prematurely because of extreme heat in New York City each year.
Not only does the EPA’s proposed reversal ignore those facts, but it also violates the EPA’s legal obligations under the federal Clean Air Act to regulate greenhouse gas emissions to address climate change.
The coalition argues, in today’s letter, that the EPA’s new legal interpretations are inconsistent with the Clean Air Act and binding Supreme Court precedent, and that the proposal would mark a drastic reversal of its own longstanding findings without any explanation grounded in science. To make matters worse, the Climate Working Group report on which the EPA relies is substantively flawed, yet the EPA blindly accepts its findings and disregards the scientific consensus, which was just reaffirmed by the National Academies of Sciences, Engineering, and Medicine last week.
In filing this comment letter, the coalition urges the EPA to abandon its proposal to rescind the 2009 Endangerment Finding.
Motor Vehicles Comment Letter
In withdrawing the 2009 Endangerment Finding, the EPA also proposes to repeal all existing federal greenhouse gas emissions standards for all motor vehicle classes and all years. In a second letter submitted to the EPA today, the coalition explains that this unprecedented disruption to the regulatory norms of the last 15 years will harm states and local governments’ residents, industries, natural resources, and public investments.
Regulatory enforcement for greenhouse gas emissions is also crucial to vehicle affordability, consumer choice, and to the success of the American automotive industry. The greenhouse gas program for vehicles incentivizes automakers to innovate and create better cars, saving drivers hundreds of billions of dollars in fuel and maintenance costs, and helps support domestic manufacturing and jobs. Repealing that program, as the EPA now proposes, will shutter factories, kill jobs, and wipe out billions of dollars in investments by Congress, states, and local governments to keep the American auto industry thriving and globally competitive.
Climate Working Group Comment Letter
Earlier this month, on September 2, the City of New York joined another coalition of 27 localities from around the nation in filing a comment letter opposing the Climate Working Group report that EPA relied on in its proposed recission of the 2009 Endangerment Finding.
In that comment letter, the coalition identified several legal flaws in the Climate Working Group report. In creating the Climate Working Group, the U.S. Department of Energy selected five widely known climate change skeptics, ignored well-established scientific integrity standards, and failed to comply with the Federal Advisory Committee Act’s procedures, which require the disclosure of all committee-related records and that committee meetings be open to the public.
The report — written in less than two months and filled with inaccuracies, factual omissions, and mischaracterizations of climate science research — attempts to critique decades of peer-reviewed scientific research establishing that the emission of greenhouse gases cause climate change and endanger public health and welfare.
In filing the comment letter, the coalition urged the Department of Energy to withdraw the unlawful and misguided Climate Working Group report.
Joining the City of New York in filing all three comment letters were the attorneys general of Arizona, California, Connecticut, Colorado, Delaware, the District of Columbia, Hawaii, Illinois, Maine, Maryland, Massachusetts, Michigan, Minnesota, New Jersey, New Mexico, New York, North Carolina, Oregon, Rhode Island, Vermont, Washington, Wisconsin, and the chief legal officers of the city and county of Denver, Colorado, Chicago, Illinois, and Martin Luther King Jr. County, Washington.
Climate Working Group Amicus Brief
On August 29, the City of New York and 19 attorneys general from around the nation filed an amicus brief in the U.S. District Court for the District of Massachusetts in Environmental Defense Fund v. Wright, supporting the plaintiffs in their effort to declare the Climate Working Group’s report unlawful.
In their brief, the coalition argued that the Department of Energy violated the Federal Advisory Committee Act by establishing and utilizing the Climate Working Group, and that this violation will harm state and local governments’ strong interest in ensuring that the federal government rely on the best available science to guide its climate policy decisions. In New York City, the New York City Panel on Climate Change uses federal climate data to develop its own reports and mapping tools, which inform many city policies, including the Climate Resilience Design Guidelines and zoning rules related to current and future flood conditions.
On September 17, the district court held that the federal government is not exempt from the Federal Advisory Committee Act.
Joining the City of New York in filing this amicus brief were the attorneys general of California, Colorado, Connecticut, Delaware, the District of Columbia, Hawaii, Illinois, Maine, Maryland, Massachusetts, Michigan, Minnesota, New Jersey, New Mexico, New York, Oregon, Vermont, Washington, and Wisconsin.
In addition to the actions described above, Elijah Hutchinson, Executive Director of the New York City Mayor’s Office of Climate and Environmental Justice, testified before EPA on August 21 to oppose its proposed recission of the 2009 Endangerment Finding and motor vehicle greenhouse gas standards.
These four actions build on the numerous actions the Adams administration has taken to protect New Yorkers from the effects of climate change. Just last week, Mayor Adams broke ground on a $218 million public safety project to protect Red Hook from coastal flooding and save hundreds of millions of dollars for residents in lost property costs. And, as announced in the Mayor’s Management Report last week, in Fiscal Year 2025, the city saw major environmental gains and savings, largely due to composting and recycling. Overall recycling tonnage increased 4 percent, and the diversion rate of recyclables rose for a third consecutive year to 21.8 percent, the highest since Fiscal Year 2011. Tons of refuse disposed to landfills decreased to the lowest level in at least 15 years, largely due to the tons of organic waste that were diverted, which increased nearly 29 percent. In 2023, Mayor Adams celebrated the passage of the “City of Yes for Carbon Neutrality” proposal, a historic set of citywide zoning changes that will facilitate climate action, clean energy, and resiliency.
