Yale Experts Explain Climate Lawsuits

Illustration of the scales of justice with earth on the left and a power plant on the right
August 16, 2023

When 16 young environmentalists won a federal lawsuit against the state of Montana in August, the ruling represented a milestone in climate change law.

The plaintiffs, who range in age from 5 to 22, successfully argued that the state’s refusal to consider climate change impacts before supporting fossil fuel development violated their right a clean environment under the Montana state constitution. Their lawsuit was the first to reach trial among several similar cases in the United States and is likely to bolster other actions seeking to use the legal system to force action on curbing emissions.

With a rapidly warming planet unleashing a host of natural disasters, activists, governments, and average citizens are increasingly asking courts to establish who bears responsibility for reducing emissions and allow recovery of costs associated with climate-related damages. That task was made easier by the Supreme Court’s April decision not to interfere with climate-related lawsuits that are filed under common law in state courts.

In a Q&A, Douglas Kysar, the Joseph M. Field ’55 Professor of Law at Yale Law School and faculty co-director of the Law, Ethics & Animals Program, explains the legal strategies behind recent climate change lawsuits, how the law could be used to protect those most vulnerable to climate disasters, and which cases may have the best chance of success.

What are climate change lawsuits? Who are the plaintiffs and what are they seeking?

Climate change lawsuits could refer to any litigation that involves climate as part of the subject matter. But when people talk about climate change lawsuits, they usually mean efforts to use the litigation process to spur climate mitigation actions or receive adaptation funding. Many cases are being brought by environmental advocacy organizations or governments who anticipate massive costs related to adapting to climate change, and they are suing to try to recover money to support those needs.

What legal claims are the plaintiffs making in these cases?

In the U.S., we’ve not had much legislation that’s specifically designed to target climate change as a problem, so when people turn to the courts you see all different kinds of theories being brought. Lawyers use securities laws to say that companies are deceiving investors by not taking account of climate change risks.  We also see people using existing environmental laws—like the Clean Air Act, Clean Water Act, or the National Environmental Policy Act—to try to force climate action. Finally, we see plaintiffs resorting to the common law—good old-fashioned tort law. The high-profile lawsuits being brought by state and local governments against fossil fuel companies often rely on a common-law cause of action called public nuisance, which is essentially the idea that the fossil fuel companies, by contributing to climate change, have harmed the general right of atmospheric stability.

Which climate lawsuits do you find most interesting, or most likely to yield a significant outcome?

There’s a case being brought by a Peruvian farmer against RWE, which is Germany’s largest electric utility and one of the largest greenhouse gas emitters in all of Europe. The farmer and his village are threatened by a glacial lake that’s increasing rapidly in volume due to runoff from melting glaciers. This lake is at risk of overtopping and causing dangerous, potentially lethal flooding to the village below.

The farmer is suing on a tort theory, saying that RWE’s contributions to climate change mean that the company is proportionately responsible for the cost of mitigating this threat—whether that’s draining the lake or reinforcing levees. RWE’s calculated share of historical global greenhouse gas emissions is estimated by the plaintiff’s experts to be around 0.47%. So when you calculate 0.47% of the estimated cost of mitigating the flood risk, it works out to around 20,000 euros. That may seem like small potatoes but if the plaintiff wins on this theory, it’s not small potatoes because that plaintiff is just one person who is kind of standing in for literally hundreds of millions of potential plaintiffs around the globe who are in a similar situation of facing clear and present dangers from the impacts of climate change. The implications are kind of earth shattering.

Infographic explaining a climate lawsuit by a Peruvian farmer against German energy company RWE

How will courts go about assigning liability for climate change—parsing out what share of the impacts can be attributed to the actions of specific companies or nations?

There are two important questions that need to be addressed in these lawsuits. One is a physical science question: To what extent can we link a climate impact with human-caused greenhouse gas emissions? That’s known as climate attribution and there’s a wonderful network of climate scientists around the world who use models to show the extent to which an extreme event—like a hurricane or heat dome—was made worse or more likely by the human contribution to global warming.

The harder nut to crack is showing that the particular defendants being sued—whether it’s a government, a company, or individuals—are responsible for the human contribution to warming. That is known as source attribution, and there are studies that use historical records such as corporate documents, mining leases, or securities filings to estimate how many tons of carbon can be attributed to particular corporate actors. It’s yet to be seen how courts will react because implicit within those studies is an assumption that the corporate actor is responsible for the emissions over the entirety of the supply chain. There’s a moral and political question about who should bear the responsibility for the end-use combustion of fossil fuels. Is it the government that authorizes and subsidizes the fossil fuel industry? Or the industry itself, which arguably has undue influence over government actors? Or the consumers and other end users who purchase and use the fuels?

Have courts generally accepted the science that climate change is human caused?

Definitely. And that’s one of the most salutary effects of these lawsuits. When you put climate science through the rigor of the litigation process, people can’t just make claims on Twitter. They actually have to prove claims based on reason and evidence and expert testimony.

In the Montana trial, the state embarrassingly listed three expert witnesses who are somewhat notorious climate skeptics. Two of those witnesses were removed from the witness list at the last minute under strange, unexplained circumstances, and the witness that did testify was pretty thoroughly discredited on cross examination.

Some are comparing these climate lawsuits to the Big Tobacco lawsuits. Is that an apt comparison? Should we expect similar outcome here?

It’s a complicated question because the history and the lessons of tobacco litigation are a lot more nuanced than we sometimes hear in popular conversation. There is definite similarity in that the lawsuits are designed to bring pressure to bear on powerful industries that are contributing to massive social harm, and that have escaped regulation through legislative or executive branch oversight.

What really caused the politics of tobacco to change in America was the fact that the lawsuits revealed the extent of corporate deceit. That kind of stigmatization of the industry, I think, is something that the litigants in the climate change lawsuits are trying to achieve by painting corporate actors like Exxon and Chevron as knowing deceivers of the American public—purveyors of harmful products that used manipulative techniques to perpetuate their market despite their knowledge of the harm that it causes.

Are there key differences between the tobacco lawsuits and the climate litigation we’re seeing now?

I think the biggest difference is that the causal chain between the industry’s arguably deceitful actions and the ultimate harmful consequences is a little more complex. With tobacco, you can tell a story that the industry marketed directly to consumers and lied to them about the health impacts of their products, so that consumers remained addicted and suffered harm as a result.

In the climate change context, you have to tell a story that the industry lied to and manipulated the American public at large in order to avoid voters and citizens putting pressure on the government to regulate the industry and stop climate change. So it becomes more like a fraud on democracy than a tighter individualized relationship in which the fraud is between a company and its customer.

In April, the Supreme Court ruled that cities and states could seek to hold energy companies accountable for climate change in state courts, not just federal courts. How significant was that ruling?

It’s hugely significant. Given the current composition of the Supreme Court, which is heavily skewed to the conservative side, it could have been quite imaginable that they would find a way to rule that climate change is of such national and international scope that it should be exclusively governed by federal common law, not state common law.

As a practical matter, it’s significant because we have 50 states and these lawsuits are being filed all over the place. The litigants are hoping to find one judge in one state in one courtroom that sees a path to allowing these cases to go to trial. Once you get to that point—where you’re past preliminary motions and you’re heading toward discovery and trial—it’s a very different balance of power between the litigants. The plaintiffs can start asking for documents and can start constructing a narrative about what the industry knew and how it acted in the face of that knowledge.

We know from experience that the people most affected by climate change may also be the ones with the least access to the judicial system. How can the legal profession ensure that they have a seat at the table going forward?

It’s a challenging issue. Access to justice, unfortunately, is often dependent on having resources and access to networks of power. The flip side, though, is that courts are open. When a person files a lawsuit, the defendant has to answer and the judge has to address the claim, whereas when we call Congress or the executive branch, they don’t have to respond to us. So there’s a way in which the judicial system and the ability to demand a response is democratizing.

We have to make available resources, lawyers, and knowledge to the people who could benefit from that. There’s a very coordinated and ambitious climate litigation community globally, and it’s not just the environmental NGOs and other activist organizations. There’s a sophisticated philanthropic community that’s supporting these actions around the world. And much of their focus is on low-lying small island states or developing countries like Pakistan and other places that are disproportionately threatened by climate impacts. There’s a gross injustice in the sense that those least responsible for climate change are often those most vulnerable to its effects, and these philanthropic organizations are doing their almighty best to try to address that injustice.

As climate suits continue to progress in the months and years ahead, what will you be watching for?

The big question, particularly in the United States, is if one of these lawsuits ever gets past preliminary motions and efforts by the industry to make it go away. If they go to discovery and are heading toward a jury trial, will that cause the industry—including its investors and board members—to feel differently about climate legislation? At that point, the industry may come to the bargaining table and say to Congress, let’s get a comprehensive climate change package passed that might include preemption of state lawsuits. So the quid pro quo would be, the fossil fuel industry will swallow a climate bill at the federal level in exchange for immunity from these tort lawsuits that are threatening them.

That would be one outcome. A counter example is when lawsuits finally started breaking through against the gun industry, the industry went to Congress with its immense power and said, just give us immunity, and they got it without anything in exchange. Essentially, they had so much power over Congress that they took the threat of lawsuits and erased it.

So the big gamble is, will these lawsuits pressure the fossil fuel industry to fundamentally change the nature of their business, or instead cause them to use their immense influence over politicians to get immunity without responsibility?

What is Yale doing on this front?

There are a lot of activities on campus and here at the Law School. One of my favorite examples is a Yale Law graduate named Stuart Beck. He’s a fascinating figure who had a long career as a diplomat for the nation of Palau, a low-lying Pacific island state that’s existentially threatened by sea level rise.

He came to Yale Law School about 10 years ago and led a class in which students from the Law School, School of the Environment, and School of Management contributed to an effort by Palau to advance a case asking the International Court of Justice to give an advisory opinion, under international law, about what nation states owe each other in terms of climate responsibility.

That campaign did not fully succeed because the U.S. State Department opposed it strongly. But it led to a report that our students produced that helped influence a set of principles known as the Oslo Principles. Those principles were cited heavily by a Dutch court that issued one of the first significant climate change rulings holding a government responsible for violating the duty of climate care.

That lawsuit has in turn catalyzed further lawsuits all around the world in dozens of countries. And in the most recent United Nations General Assembly session, the small island state of Tuvalu picked up the baton from Palau and reignited the campaign to request an advisory opinion from the International Court of Justice. This time, the U.S. State Department did not formally oppose it. It went through overwhelmingly in a near unanimous vote at the General Assembly, so the International Court of Justice will likely accept jurisdiction and issue this extremely consequential ruling on climate responsibility.

It’s often difficult to trace exactly what your intervention is contributing to a very complex and global problem like climate change. But in that case, we had a class of Yale Law students and other Yale students who I think helped move the needle on something quite dramatically.