In my previous blog essay (November 28, 2025), I offered my thought on Key Takeaways from COP30 in Belém, and today I’m pleased to provide insights from energy economist Catherine Wolfram, who shared her thoughts on the 30th Conference of the Parties of the United Nations Framework Convention on Climate Change (COP30) and on the prospects for climate coalitions to significantly reduce CO₂ emissions, 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.
Wolfram, the William Barton Rogers Professor of Energy Economics at the MIT Sloan School of Management, spent several days at COP30 in Belém, Brazil last month, and concluded that although the negotiators did not close the conference with a strong statement about phasing down fossil fuel use, there were some quite positive aspects of COP30, including the fact that no other countries joined the U.S. in withdrawing from the Paris Climate Agreement.
“I think in some ways Brazil pulled a victory from the jaws of defeat in that way,” she says. “Not having the U.S. there really hurt things [because] the U.S. is usually a force against the Saudi Arabias and the Russias and can help get stronger statements on phasing out fossil fuels or climate ambition, whatever it is into the text. And so that was one of the results of not having the U.S. there. But as I say, not by any means the worst result that we could have seen.”
Catherine, who co-leads the Global Climate Policy Project at Harvard and MIT (GCPP), observes that Brazil’s Open Coalition on Compliance Carbon Markets, launched in Belém during the COP, aligns very well with the research being conducted by GCPP.
“While the COPs and the Paris Climate Agreement are important, we need more. We need to be thinking about additional ways to push forward at a global scale on climate. And so, [researchers at GCPP] have several projects thinking about geoengineering, thinking about climate finance, thinking about industrial policy, but the project where we’ve had the most impact and made the most progress so far is the project on climate and trade. So yes, as you say, we were absolutely thrilled to see Brazil’s declaration on the Open Coalition on Compliance Carbon Markets.”
Wolfram and her team at GCPP recently released a detailed report intended to help policymakers envision what a climate coalition could look like.
“One of our scenarios was the conventional scenario [in which] every country to join the coalition would have to have a minimum carbon price, and there would be one minimum. But then another scenario that we outlined…allowed for graduated admission criteria. So, the low- and middle-income countries could get into the coalition at say one third the carbon price that a high-income country would need to get into the coalition and middle-income countries could join for two thirds,” she explains. “I do think that it helps recognize fairness issues and fairness challenges so that you’re letting low- and middle-income countries essentially use more of the remaining carbon budget if they have a lower carbon price to get in. And I think it helps make this a little bit more realistic than some of the stricter interpretations of the climate club where everyone has to have the same price.”
In order to entice low- and middle-income countries to join a climate coalition and set prices on carbon, Catherine says that there need to be additional levers in place to support them.
“We thought about a kind of targeted climate finance. We thought about having free trade and the inputs to decarbonization… I think the other thing that we did to try to make this actionable and have some chance of getting off the ground in the near term was to focus on a couple industries,” she says. “There’s the European Union Carbon Border Adjustment Mechanism (CBAM) that’s starting in several weeks, and that is initially targeting the aluminum, steel, fertilizer, and cement industries. And so, in our report, we imagined that coalition membership initially just requires carbon prices for those industries.”
The CBAM model can be a very effective tool for inciting climate action on a national or regional level, Wolfram argues.
“Turkey is a prime example. Turkey has explicitly said that because of the CBAM, they themselves are pursuing an emissions trading system. And they’re even thinking about enacting a CBAM. Once you’re charging carbon prices to your domestic industry, it makes sense to think about leveling the playing field for them and making sure that imports face that carbon price as well,” she says. “There are other examples of countries that have either introduced carbon prices or expanded their carbon pricing systems. For instance, China, a huge, huge emitter, especially in the CBAM sectors, expanded their carbon pricing system from covering just the electricity sector to covering also steel, aluminum, and cement… And Brazil, India, lots and lots of countries are planning to implement carbon prices.”
For this and much, much more, I encourage you to listen to this 72nd 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
“Environmental Insights” is hosted on SoundCloud, and is also available on iTunes, Pocket Casts, Spotify, and Stitcher.
