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Climate Rollbacks Could Trigger a Wave of Lawsuits

April 29, 2026 / 11:49

This episode discusses the Trump Administration's repeal of the endangerment finding, its implications for the EPA, and potential public nuisance lawsuits against power plant owners.

Sarah Light, a Professor of Legal Studies and Business Ethics at the Wharton School, explains how the endangerment finding allows the EPA to regulate air pollutants under the Clean Air Act. The repeal could prevent the EPA from issuing regulations related to greenhouse gas emissions.

Light uses an analogy of a hotel room key to illustrate how the endangerment finding enables the EPA to take regulatory action. Without it, the agency may lack the authority to address greenhouse gas emissions effectively.

The conversation also covers ongoing litigation against fossil fuel companies by states and cities, which may gain momentum if the repeal is upheld. Light notes that the absence of a comprehensive federal statute could lead to increased tort litigation.

Finally, the episode touches on the potential for significant court filings and motions in the coming months, with the possibility of the Supreme Court being involved in future decisions related to climate regulation.

TLDR

The episode covers the Trump Administration's repeal of the endangerment finding and its potential impact on EPA regulations and climate lawsuits.

Episode

11:49
00:00:00
The push by the Trump Administration away from climate regulation continues with the repeal of the endangerment finding.
00:00:07
It's what led the EPA to take action to curb emissions on various pollutants,
00:00:11
doing so under the Clean Air Act. But by making this determination, it may actually open the door to
00:00:18
potentially a wave of public nuisance lawsuits against power plant owners. To discuss this, a pleasure to be joined once again by Sarah Light,
00:00:27
who's a Professor of Legal Studies and Business Ethics here at the Wharton School.
00:00:31
Sarah, great to catch up with you again. How are you? I'm doing great, Dan. Thanks so much for inviting me today.
00:00:37
I'm always happy to chat with you. Thank you. What is it that the administration, I guess let's start there, sees as a
00:00:45
benefit by taking this action in the first place? Great. So in order to answer that question, if you'll permit me, I want to just give
00:00:52
you a little bit of background about how the Clean Air Act works. So the Clean Air Act, you know, is a federal law that allows the
00:01:00
government through the EPA to issue regulations to address air pollutants, largely from stationary sources of emissions, like power plants or industry,
00:01:11
as well as from mobile sources like vehicles, trucks, cars, SUVs. Certain pollutants were designated kind of early on. You know, methane, carbon
00:01:24
monoxide, nitrogen oxides, but the statute gives the administration some degree of
00:01:30
flexibility to determine later on, you know, with more scientific knowledge, that a different substance constitutes an air
00:01:39
pollutant that endangers public health and welfare. And before the EPA is allowed to issue any regulations addressing that air pollutant,
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it must make what's called an endangerment finding. So back in, you know, the 2000s, under the Obama Administration,
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the EPA issued this endangerment finding concluding that greenhouse gas emissions,
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the six greenhouse gases under the Kyoto Protocol at the time, constituted air pollutants under the Clean Air Act that cause or contribute
00:02:10
to air pollution that endangers public health and welfare. Okay, so the analogy that I like to give is, have you ever been in a hotel room?
00:02:20
And when you go into the hotel room, you walk in, and you try to turn on the lights, and you can't turn on the lights. You
00:02:26
have to put your key into a slot by the door. Right. And once you put your key into the slot, then you can turn the lights on.
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- Right. - Right. So the endangerment finding is the EPA putting its key in the slot that then
00:02:41
allows it to issue regulations to address that air pollutant. So in 2009, the EPA issued the endangerment finding, lots of scientific
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evidence demonstrating this, you know, harm to human health and the environment.
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And then subsequently, the EPA issued regulations to address greenhouse gas emissions from power plants, to address greenhouse gas emissions from motor vehicles.
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Okay. So I realize I'm going on for a while, but I hope this is helpful background. - No, yeah.
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Feel free to interrupt me at any time. So subsequently, the Obama Administration issues
00:03:19
greenhouse gas regulations for power plants and cars. Trump is elected. He leaves the endangerment finding in place, but issues
00:03:28
weaker regulations for power plants and for cars. Biden comes into power, stronger regulations for power plants and vehicles,
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and then Trump two comes in. And instead of just trying to repeal the regulations that the Biden Administration
00:03:49
adopted, they're going kind of for the nuclear option. - Right. Which is taking the key out of that slot by the door at the hotel.
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So if the endangerment finding repeal is upheld by the courts, that essentially deprives the EPA the ability to issue regulations.
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You can't turn on the lights, you know, somewhere else in the room, if that makes sense.
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So the Trump Administration has taken a different approach this time. They are simultaneously attempting to repeal
00:04:20
the regulations, turning off the lights. Right. So they're taking both steps.
00:04:27
If either one is successful, there will be a loss of regulation. But if the endangerment finding is gone, that basically means the EPA cannot issue
00:04:37
greenhouse-gas-related limitations. And I'll just mention one other thing. The way that the Trump Administration has tried to repeal the endangerment finding
00:04:49
is by focusing on motor vehicles and motor vehicle emissions. Right. - But if it's upheld— - - In part, probably, because of the
00:04:57
California standards, I would think. In part because of the California standards, in part because of the
00:05:02
potential for litigation over power plant emissions and things like that. So— but that's— I think the analogy of the key
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in the hotel room is very helpful to understand. It's like, without this, you can't turn on the regulations.
00:05:18
But it sounds like, and I don't know if this was intentional or not, but that the—
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one of the consequences is, from your comments and the reporting about this, is that this does open the door to potential legal challenges in the court
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system about what some of these electric companies and power plant owners are doing, correct?
00:05:43
That's right. So it's a little bit complicated, but I do think that it raises the
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possibility of significant additional litigation. So throughout this time period, when there's been pressure from
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environmental groups for the EPA to regulate greenhouse gas emissions and pressure from other groups not to regulate greenhouse gas emissions, certain
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government entities like states, cities, you know, the city of Hoboken, the state of— you know, the city of X.
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They have brought tort litigation against power plants and other fossil fuel companies seeking damages, basically saying you have contributed to climate
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change, our our infrastructure is eroding, you profited, you owe us money. It's like any kind of standard tort litigation. You've done me wrong.
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I need compensation. Relatively straightforward. Okay. So because a case like this went up to the Supreme Court and the
00:06:48
Supreme Court basically said, "Look, the Clean Air Act allows for the regulation of greenhouse gas emissions nationwide as a system."
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And so we're not going to have these tort suits being brought by, you know, the city of San Mateo, California and the city of Hoboken, piecemeal around the
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country and have individual judges tell power plants, you know, how much they need to pay or what they need to do.
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So basically, because there's this comprehensive statutory scheme, the Clean Air Act, which allows for the regulation of greenhouse gas emissions,
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we're not going to allow these tort cases to proceed, at least not under federal law.
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Right. After that, everyone tried— you know, it's like a game of whack-a-mole.
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So the entities that were trying to bring these suits started, "Okay, well, we'll bring them under state law.
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We'll bring them under California law, under Rhode Island law, Massachusetts law," etc.
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And it has— those cases have generally proceeded. And they are proceeding in the courts. There have not
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necessarily been judgments against the fossil fuel producers. But the fossil fuel producers are making the same argument.
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They're basically— they basically have been saying, "Look, same deal under state law.
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The Clean Air Act allows for the, you know, regulation of greenhouse gas emissions on a nationwide scale, this shouldn't
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be a bunch of different state tort cases." And the courts are kind of divided a little bit on that.
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But if the Trump Administration is now taking the position that the Clean Air Act
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does not cover greenhouse gas emissions, they are not an air pollutant under the
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Clean Air Act, then we're in a different universe with respect to these state tort
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cases, because there is no comprehensive federal statute that deals with this on a nationwide basis.
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And when there is no comprehensive nationwide federal statute dealing with a particular issue, often tort law,
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and in this case specifically, nuisance law, comes in as a kind of background system to allow parties to address harms to them.
00:08:56
So my view is that it is— that if you repeal the endangerment finding, you open up the potential for tort litigation.
00:09:04
Right, right. And I guess, are we already starting to hear of organizations lining up
00:09:10
potentially to prepare suits against these utility companies and power plant owners?
00:09:16
Well, so there are already suits in play. That's the thing. There are already— there's literally litigation happening right now.
00:09:25
And so, you know, we don't even need new additional suits to be filed to test this.
00:09:31
But we'll see what happens, right? We'll see what happens. What do you expect then to see?
00:09:36
What will we see play out here potentially, in what sounds like it could be months and years
00:09:43
ahead with the litigation we're going to see? Right. So, I hope not years. I hope it's only months. But I do imagine that there will be, you know, significant
00:09:55
motions practice and, you know, filings in the courts as they make the determination about whether to uphold the repeal.
00:10:03
Initially, that decision is being made at the level of the court of appeals, but there's no question that whoever loses is going to take it to the Supreme Court.
00:10:11
Right. Exactly. - And so— so, you know, that's going to— that certainly won't happen this term.
00:10:17
The term ends in June. They've already, you know, taken all the cases, essentially, that they're going to take this year.
00:10:25
So that would be next year. And often the blockbuster cases are the ones that get decided at the end of the term.
00:10:30
So we could be looking at a full year. And how similar then could potentially this kind of framework of litigation be to
00:10:39
what we saw the Supreme Court rule on back in, I guess it was 2011, correct? Yeah, absolutely right.
00:10:46
Well, 2011 was Connecticut versus AEP, right? So that was the case where the state of Connecticut and other governments sued
00:10:54
American Electric Power under the federal common law of nuisance. And the Supreme Court said, you know, "Too bad, so sad."
00:11:01
The Supreme Court is considering a nuisance case in the coming term. That may end up being a vehicle. You know, unclear.
00:11:15
I don't— I can't totally predict what the timing is going to be, but that's the risk.
00:11:20
- Right. - That's the risk, I think. Sarah, always great to talk with you and get some insight on this.
00:11:26
And we will stay in touch as this develops down the road. Thank you. Thanks, Dan.
00:11:31
You got it. Sarah Light, Professor of Legal Studies and Business Ethics here at the Wharton School.

Episode Highlights

  • Endangerment Finding Repeal
    The Trump Administration's repeal of the endangerment finding could halt EPA regulations.
    “If the endangerment finding is gone, that basically means the EPA cannot issue regulations.”
    @ 04m 37s
    April 29, 2026
  • Litigation Potential
    Repealing the endangerment finding may open the door to significant tort litigation.
    “If you repeal the endangerment finding, you open up the potential for tort litigation.”
    @ 09m 01s
    April 29, 2026

Episode Quotes

  • Without this, you can’t turn on the regulations.
    Climate Rollbacks Could Trigger a Wave of Lawsuits
  • I hope it’s only months. But I do imagine significant motions practice.
    Climate Rollbacks Could Trigger a Wave of Lawsuits

Key Moments

  • Legal Challenges Loom05:36
  • Litigation in Progress09:19
  • Future Uncertainty09:49

Tension Over Time

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