On February 12th, 2026, the U.S. Environmental Protection Agency (EPA) finalized its rescission of the 2009 Greenhouse Gas Endangerment Finding. This action by the Trump administration reversed the scientific determination that greenhouse gases (GHGs) threaten public health and welfare, effectively removing the legal basis for federal regulations on GHG emissions from vehicles, power plants, and other sources. This has received a great deal of press coverage, but to really understand the implications, it is helpful to understand the gestation and evolution of the Endangerment Finding. And for that there is no one better in the world to guide us through the political and legal history, and the path going forward, than my colleague, Jody Freeman, the Archibald Cox Professor of Law at Harvard Law School. Our conversation is featured in the latest episode of my podcast series, “Environmental Insights: Discussions on Policy and Practice from the Harvard Environmental Economics Program.” Listen to our conversation here.
When the Trump administration announced in July 2025 its intention to rescind the Endangerment Finding, it based that upon both legal and scientific grounds, in particular an exceptionally flawed study authored by five rather prominent climate skeptics and published by the U.S. Department of Energy. Apparently the administration came to realize that the claimed scientific basis for rescission would be challenged successfully in court, and so when the recission was actually finalized a couple of weeks ago, the administration explicitly excluded the scientific grounds (and the DOE study), presumably realizing they would lose in court. Instead, the recission is being justified on purely legal grounds. For example, the argument is made that the Clean Air Act “does not authorize the Agency to prescribe emission standards in response to global climate change concerns.” Also, the claim is made that the 2022 Supreme Court decision striking down the Obama power plant rule prohibits EPA from regulating global pollutants. These legal arguments mean that future administrations cannot limit GHG emissions without new legislation by Congress. So, clearly, Professor Freeman is a perfect person to unpack all of this.
I began our conversation by asking about the history of the Endangerment Finding, which Jody Freeman explained emerged from the verdict in the 2007 Massachusetts vs. EPA Supreme Court case in which the court ruled that GHGs are pollutants that could be covered by the Clean Air Act if EPA found that these gases “endanger public health and welfare.”
“The Obama administration took the scientific analysis that EPA had already done, updated it, and made the endangerment finding for greenhouse gases,” she notes. “The first set of standards was for emissions from new cars and trucks under section 202 of the law. Interestingly, that is the section that the Trump administration now is claiming it does not have the authority under to make this endangerment finding or set these car [fuel efficiency] standards.”
Freeman explains that the Trump administration is also contending that it would be futile to regulate greenhouse gas emissions from vehicles because the emissions from new cars and trucks are a very small fraction of overall emissions.
“This really is a rehash of the losing arguments in Massachusetts versus EPA,” she points out. “They look slightly different. They’re articulated slightly differently, but the heart of it is the same. So, in my view, they’re really taking another run at the losing side of the argument.”
The administration’s strategy, Freeman suggests, is based on the calculation that today’s Supreme Court will likely be much more sympathetic to their arguments than was the Court as it existed in 2007.
“It’s a risky thing for this administration to now take a run at it, but I speculate that their thinking is, well, we have three justices on the Supreme Court… who were in the dissent in Mass. versus EPA, including the Chief Justice, and all of the members of the majority from Massachusetts versus EPA are gone… and we have a new conservative Supreme Court, maybe we can pick up a couple of other votes and it’s worth taking a run at it,” she says.
Not surprisingly, Freeman finds it difficult to predict how the high court will rule, but she provides several possibilities.
“I can imagine a place where the Supreme Court might land where it doesn’t quite say that EPA lacks authority to regulate global pollution because that would contradict what it said in Mass. versus EPA, but it’s possible they would find something in the language of contribution to rule for the administration. I don’t think that would be the right reading of the law, but I certainly think EPA is hoping for it.”
But either way, Freeman argues, it will likely be several years before a final verdict is rendered.
“Even if this does reach the Supreme Court, it will be quite some time, and it will pretty much run out the clock on the administration,” she says. “So, we’re not going to see any greenhouse gas rules likely from this administration between now and the time they leave office.”
Finally, should the high court eventually rule for the administration, Freeman explains, the federal government would be virtually powerless to regulate emissions.
“That would knock out the Clean Air Act as a source of federal climate regulations because if they can’t make an endangerment finding [applicable] for cars and trucks, then they can’t make an endangerment finding anywhere in the Clean Air Act [in order to] regulate global pollution. So, if the court were to go for that argument, then Congress would need to amend the law to restore EPA’s authority to set greenhouse gas standards.” Sobering but honest thoughts.
For this and much, much more, I encourage you to listen to this 73rd episode of the Environmental Insights series, with future episodes scheduled to drop each month. You can find a transcript of our conversation at the website of the Harvard Environmental Economics Program. Previous episodes have featured conversations with:
- Gina McCarthy, former Administrator of the U.S. Environmental Protection Agency
- Nick Stern of the London School of Economics discussing his career, British politics, and efforts to combat climate change
- Andrei Marcu, founder and executive director of the European Roundtable on Climate Change and Sustainable Transition
- Paul Watkinson, Chair of the Subsidiary Body for Scientific and Technological Advice (SBSTA) within the United Nations Framework Convention on Climate Change
- Jos Delbeke, professor at the European University Institute in Florence and at the KU Leuven in Belgium, and formerly Director-General of the European Commission’s DG Climate Action
- David Keith, professor at Harvard and a leading authority on geoengineering
- Joe Aldy, professor of the practice of public policy at Harvard Kennedy School, with considerable experience working on climate change policy issues in the U.S. government
- Scott Barrett, professor of natural resource economics at Columbia University, and an authority on infectious disease policy
- Rebecca Henderson, John and Natty McArthur University Professor at Harvard University, and founding co-director of the Business and Environment Initiative at Harvard Business School.
- Sue Biniaz, who was the lead climate lawyer and a lead climate negotiator for the United States from 1989 until early 2017.
- Richard Schmalensee, the Howard W. Johnson Professor of Management, and Professor of Economics Emeritus at the Massachusetts Institute of Technology.
- Kelley Kizier, Associate Vice President for International Climate at the Environmental Defense Fund.
- David Hone, Chief Climate Change Adviser, Shell International.
- Vicky Bailey, 30 years of experience in corporate and government positions in the energy sector.
- David Victor, professor of international relations at the University of California, San Diego.
- Lisa Friedman, reporter on the climate desk at the The New York Times.
- Coral Davenport, who covers energy and environmental policy for The New York Times from Washington.
- Spencer Dale, BP Group Chief Economist.
- Richard Revesz, professor at the NYU School of Law.
- Daniel Esty, Hillhouse Professor of Environment and Law at Yale University.
- William Hogan, Raymond Plank Research Professor of Global Energy Policy at Harvard.
- Jody Freeman, Archibald Cox Professor of Law at Harvard Law School.
- John Graham, Dean Emeritus, Paul O’Neill School of Public and Environmental Affairs, Indiana University.
- Gernot Wagner, Clinical Associate Professor at New York University.
- John Holdren, Research Professor, Harvard Kennedy School.
- Larry Goulder, Shuzo Nishihara Professor of Environmental and Resource Economics, Stanford University.
- Suzi Kerr, Chief Economist, Environmental Defense Fund.
- Sheila Olmstead, Professor of Public Affairs, LBJ School of Public Affairs, University of Texas, Austin.
- Robert Pindyck, Bank of Tokyo-Mitsubishi Professor of Economics and Finance, MIT Sloan School of Management.
- Gilbert Metcalf, Professor of Economics, Tufts University.
- Navroz Dubash, Professor, Centre for Policy Research, New Delhi.
- Paul Joskow, Elizabeth and James Killian Professor of Economics emeritus, MIT.
- Maureen Cropper, Distinguished University Professor, University of Maryland.
- Orley Ashenfelter, the Joseph Douglas Green 1895 Professor of Economics, Princeton University.
- Jonathan Wiener, the William and Thomas Perkins Professor of Law, Duke Law School.
- Lori Bennear, the Juli Plant Grainger Associate Professor of Energy Economics and Policy, Nicholas School of the Environment, Duke University.
- Daniel Yergin, founder of Cambridge Energy Research Associates, and now Vice Chair of S&P Global.
- Jeffrey Holmstead, who leads the Environmental Strategies Group at Bracewell in Washington, DC.
- Daniel Jacob, Vasco McCoy Family Professor of Atmospheric Chemistry & Environmental Engineering at Harvard.
- Michael Greenstone, Milton Friedman Distinguished Service Professor of Economics, University of Chicago.
- Billy Pizer, Vice President for Research & Policy Engagement, Resources for the Future.
- Daniel Bodansky, Regents’ Professor, Sandra Day O’Connor College of Law, Arizona State University.
- Catherine Wolfram, Cora Jane Flood Professor of Business Administration, Haas School of Business, University of California, Berkeley, currently on leave at the Harvard Kennedy School.
- James Stock, Harold Hitchings Burbank Professor of Political Economy, Harvard University.
- Mary Nichols, long-time leader in California, U.S., and international climate change policy.
- Geoffrey Heal, Donald Waite III Professor of Social Enterprise, Columbia Business School.
- Kathleen Segerson, Board of Trustees Distinguished Professor of Economics, University of Connecticut.
- Meredith Fowlie, Professor of Agricultural and Resource Economics, U.C. Berkeley.
- Karen Palmer, Senior Fellow, Resources for the Future.
- Severin Borenstein, Professor of the Graduate School, Haas School of Business, University of California, Berkeley.
- Michael Toffel, Senator John Heinz Professor of Environmental Management and Professor of Business Administration, Harvard Business School.
- Emma Rothschild, Jeremy and Jane Knowles Professor of History, Harvard University.
- Nathaniel Keohane, President, C2ES.
- Amy Harder, Executive Editor, Cypher News.
- Richard Zeckhauser, Frank Ramsey Professor of Political Economy, Harvard Kennedy School.
- Kimberly (Kim) Clausing, School of Law, University of California at Los Angeles
- Hunt Allcott, Professor of Global Environmental Policy, Stanford Doerr School of Sustainability.
- Meghan O’Sullivan, Jeane Kirkpatrick Professor of the Practice of International Affairs at Harvard Kennedy School.
- Robert Lawrence, Albert Williams Professor of International Trade and Investment, Harvard Kennedy School.
- Charles Taylor, Assistant Professor of Public Policy, Harvard Kennedy School.
- Wolfram Schlenker, Ray Goldberg Professor of the Global Food System, Harvard Kennedy School.
- Karen Fisher-Vanden, Professor of Environmental & Resource Economics, Pennsylvania State University
- Max Bearak, climate and energy reporter, New York Times
- Vijay Vaitheeswaran, global energy and climate innovation editor, The Economist
- Joseph Aldy, Teresa & John Heinz Professor of the Practice of Environmental Policy, Harvard Kennedy School
- Nicholas Burns, Roy and Barbara Goodman Family Professor of the Practice of Diplomacy and International Relations, Harvard Kennedy School
- Elaine Buckberg, Senior Fellow, Salata Institute for Climate and Sustainability, Harvard University
- Anna Russo, Junior Fellow, Harvard University
- John Podesta, Advisor to Presidents Clinton, Obama, and Biden
- Catherine Wolfram, William Barton Rogers Professor of Energy Economics, MIT Sloan School of Management
“Environmental Insights” is hosted on SoundCloud, and is also available on iTunes, Pocket Casts, Spotify, and Stitcher.
