Climate Change is sparking a litigation boom across the globe—both to advance and delay action on climate change—with nearly 70 percent of cases playing out in U.S. courts, a report published Thursday said.
The report, compiled by the U.N. Environment Programme (UNEP) and Columbia Law School’s Sabin Center for Climate Change, said there were 2,180 “climate change” cases between 2020 and 2022.
To be included in the report, a lawsuit must raise material issues of fact or law relative to climate change mitigation (the reduction of greenhouse gas emissions), adaptation (preparing for climate impacts like intense heating and storms) or science (the growing body of attribution science that uses statistical models and weather data to glean insights into how much a particular polluter contributed to an extreme event). The report excludes cases that merely mention climate change or that are only tangentially related to it, like litigation over deforestation or the human health impacts of air pollution.
The report is the third in a series that began in 2017 and is based upon data compiled in the Sabin Center’s Climate Change Litigation Database. Over the course of five years, cases have more than doubled across an expanding number of jurisdictions, jumping from 24 to 65 judicial forums.
That growth is “unprecedented,” according to Maria Antonia Tigre, one of the report’s authors and a senior fellow at the Sabin Center. Tigre and her co-authors wrote that the field of law around climate change is becoming “increasingly well-defined.”
The majority of climate cases are filed by plaintiffs seeking outcomes that are aligned with goals under the Paris Agreement to limit global warming to 1.5 degrees Celsius compared to pre-industrial levels. Those suits are primarily aimed at holding governments accountable to their climate commitments, challenging governmental action or inaction with regard to emissions or adaptation to climate change, affecting corporate and investor behavior, and establishing liability primarily of fossil fuel companies for harm caused by the effects of climate change, such as extreme weather events.
Success in Court
The lawsuits are based on an increasingly wide range of legal bases including human rights laws; administrative laws like environmental impact statements and zoning laws; private law claims such as nuisance, trespass and negligence; corporate laws such as shareholder disclosure obligations and corporate governance; and consumer protection laws targeting “greenwashing” (making misleading claims about actions taken to combat climate change), among others.
Activists’ lawsuits have seemingly paid off, according to the Intergovernmental Panel on Climate Change (IPCC), which last year said in its sixth assessment of climate change that litigation has played a role in affecting “the outcome and ambition of climate governance.”
In 2021, a German court, for instance, invalidated sections of Germany’s Federal Climate Protection Act, finding that the law conflicted with constitutional rights, such as the rights to life and health. In response, the government enacted a new law with steeper emission cuts—and a new lawsuit challenging that law’s sufficiency is currently pending.
The IPCC report, signed off on by 195 governments, also indicated that liability from climate-related litigation has created new risks for financial investments in fossil fuel companies.
The reasons for the uptick in climate cases are various, but include the enactment of new national laws and international commitments, as well as increasing public awareness about climate change impacts and the urgency needed to address it, Tigre said. Other possible causes are improvements in the climate attribution science used to prove causation between polluters and the effects of climate change, as well as the success of prominent cases like the 2021 Milieudefensie et al. v. Royal Dutch Shell litigation in The Hague that required the oil major Shell to cut its emissions by 45 percent compared to 2019 levels by 2030. Shell has since moved its headquarters to the United Kingdom and appealed the ruling.
The Litigious United States
The United States’ surfeit of climate cases—1,522 of the 2,180 indexed—likely comes down to the nations’ history of litigiousness, according to Tigre. But all of that litigation has not necessarily translated into systemic shifts in climate governance within the world’s largest historical greenhouse gas emitter. That’s unlike the Netherlands, Belgium and Germany, where strategic litigation has won court rulings forcing national governments to enact plans that more steeply cut greenhouse gas emissions, the report said.
Instead, a large chunk of the U.S. cases have come from over two dozen state and local governments seeking damages from fossil fuel companies for their products’ contribution to global warming, among other claims. Those cases, which have faced lengthy procedural delays over whether the cases should be heard in federal or state court, are set to move forward after the U.S. Supreme Court ruled in April that the suits should be heard in state courts—where companies could face more plaintiff-friendly juries.
Other notable U.S. climate cases captured in the report are two youth-led lawsuits, Juliana v. United States and Held v. State, that are pending in federal court and Montana state court, respectively. In Juliana, the plaintiffs allege that the U.S. government violated the youths’ constitutional rights to life, liberty and property by failing to control greenhouse gas emissions. In Held, the plaintiffs are asking the court to recognize a human right to a stable climate and to force the Montana state government to enact a plan to reduce climate-warming emissions.
Tigre said it is likely that the current composition of the U.S. Supreme Court has affected American litigants’ strategies since the 6-3 conservative leaning court has indicated it is more business friendly.
In 2022, that dynamic played out when the high court ruled in West Virginia v. EPA that the U.S. Environmental Protection Agency lacked authority under the Clean Air Act to regulate carbon dioxide emissions from power plants. The ruling was widely seen as a blow to the Biden administration’s efforts to reduce U.S. greenhouse gas emissions by 50 percent compared to 2005 levels, a key step toward achieving U.S. commitments under the Paris Agreement.
At the same time, U.S. plaintiffs seeking to force action on climate change have had victories in recent years, including in the 2023 case Friends of the Earth v. Haaland, which ruled that Environmental Impact Assessments (official documents that evaluate the environmental impacts of a law or policy) must consider climate change impacts.
In that case, the D.C. Circuit Court of Appeals overturned an offshore lease sale for oil and gas development in the Gulf of Mexico, finding that the EIA was deficient for not considering the greenhouse gas emissions linked to the sale. At least two other cases (Biological Diversity v. Bernhardt; and Food & Water Watch v. FERC) had similar rulings regarding EIAs. These victories are likely to spur similar future litigation, Tigre said.
Greenwashing and climate-related disclosure litigation have also taken off in U.S. courts, with state and local governments pursuing fossil fuel companies over claims addressing climate change. In one case, the state of Connecticut sued ExxonMobil on grounds that the oil company violated state consumer protection laws by allegedly creating uncertainty about climate science.
Trump, Bolsonaro Trigger Litigation
Much of the uptick in U.S. litigation took place during the Donald J. Trump presidency and was likely in response to governmental backsliding on climate action, according to Andrew Raine, one of the report’s authors and UNEP’s head of International Environmental Law Unit. Researchers noticed a similar trend in Brazil during Jair Bolsonaro’s presidency. New climate litigation in both countries has leveled off under new leftist administrations.
Following the United States, the jurisdictions with the largest number of pending climate change cases are the European Union, Australia, United Kingdom, Germany, Canada and Brazil. Meanwhile, the report lists only two cases out of China, the world’s top greenhouse gas emitter by far, though its per capita emissions are ranked much lower. The dearth of litigation there is partly attributed to the country’s lack of significant climate legislation—Climate Action Tracker lists China’s domestic policies as “highly insufficient” to meet Paris Agreement goals. China’s repressive one-party system also has only very narrow avenues for advocates to challenge governmental actions, has limited public debate related to climate change and courts hold limited power over the government. Asia as a whole has only a small fraction of cases tracked—6.6 percent of worldwide cases excluding the U.S. portion. Tigre said she expects to see an uptick in litigation across the region going forward in part because of a landmark report issued by a Philippines human rights commission in 2022.
The report, released after a seven-year investigation into 47 fossil fuel companies alleged responsibility for human rights abuses, found that the companies engaged in “willful obfuscation and obstruction to prevent meaningful climate action.” The report established that the companies have a legal duty to engage in human rights due diligence and to avoid causing human rights violations through harm to the climate. Though nonbinding, legal experts expect litigants to rely on the report in future lawsuits.
Climate Change and Human Rights
The UNEP-Sabin Center report also captures complaints filed with quasi-judicial bodies like the U.N. Human Rights Committee, which doesn’t have binding authority but is an institution that carries moral and persuasive weight with national governments.
In 2022, the Committee handed down a historic ruling in Daniel Billy and others v. Australia, finding that the Australian government violated the human rights of Indigenous Torres Strait Islanders by failing to adequately protect them from the severe impacts of climate change. The case is part of an emerging body of jurisprudence tying together human rights law and climate change.
Another U.S. based human rights case is pending before the U.N. special procedures by Native American tribes in Louisiana and Alaska over those communities’ climate-caused displacement from their ancestral lands in violation of their rights to life, self-determination, food security and safe drinking water, among other violations.
These types of human rights cases invoking constitutional and international human rights have placed a human face on “here and now” of climate impacts like extreme heat, ocean acidification, sea level rise, biodiversity loss and more intense storms, Tigre said.
The UNEP-Sabin Center report calls the use of human rights “one of the most visible categories of climate cases,” that have catalyzed changes even when plaintiffs do not outwardly prevail. In Sacchi, et al. v. Argentina, et al., for instance, the U.N. Committee on the Rights of the Child rejected on procedural grounds a plea from youths claiming that their governments violated their rights under the Convention on the Rights of the Child by failing to make adequate emission cuts. Despite being dismissed, the petition generated “positive” guidance for pro-climate action plaintiffs: the Committee’s ruling stated, among other things, that governments’ acts or omissions regarding greenhouse gas emissions are “reasonably foreseeable,” contribute to the harmful effects of climate change and have extraterritorial consequences. Future plaintiffs and other courts may rely on that language in mounting new legal challenges. That sort of cross-pollination between different judicial bodies is yet another trend noted in the report.
“Sometimes the law in one jurisdiction doesn’t have the answers to the problems we’re addressing so judges are open to looking at other jurisdictions for answers,” Tigre said.
There are three pending international cases that could catalyze a ripple effect across national courts. Petitions filed over the past year with the International Court of Justice, the International Tribunal on the Law of the Sea, and the Inter-American Court of Human Rights all seek non-binding advisory opinions on legal obligations of nations with respect to climate change, including the obligations to future generations and obligations to address climate change. Depending on the outcome, national court judges could rely on the advisory opinions to force governments and polluting companies to reduce emissions or compensate plaintiffs for climate-related injuries.
The Road Ahead
Looking ahead, the UNEP-Sabin Center report indicates that hot topics in future cases may center around nation’s extraterritorial responsibility for climate change, climate migration, pre- and post- disaster suits related to adaptation, cases brought by vulnerable groups like Indigenous peoples who are disproportionately affected by climate change, and increases in so-called “backlash cases” that seek to delay or discourage actions to prevent and mitigate against global warming.
Between 2010 and 2014, there were at least 14 “backlash” cases filed against governments under international investment laws through a mechanism known as Investor-State Dispute Settlements (ISDS). The cases emanate from government acts that directly or indirectly affect investments of foreign companies, including regulations intended to address climate change. While ISDS lawsuits do not directly challenge climate-related regulations, they have the potential to chill future regulation as governments try to avoid costly litigation—on top of attorneys fees and court costs, ISDS judgements can run into the hundreds of millions or billions of dollars. In Rockhopper v. Italy, an ISDS tribunal ruled in 2022 that the Italian government engaged in unlawful expropriation for denying the British oil and gas company a production concession in an offshore oil field. Rockhopper was awarded about $265 million in compensation.
The IPCC’s latest report also listed ISDS cases as an impediment to future governmental action on climate.
Other backlash cases listed in the report include suits filed against climate activists for acts of civil disobedience, as well so-called “just transition” cases that seek to protect workers and other communities vulnerable to disruptions brought on by the global transition to clean energy, such as communities living near deposits of minerals used in clean energy technologies.
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While the UNEP-Sabin Center report does not evaluate the success rate of various climate lawsuits, a similar report from the London School of Economics’ Grantham Institute found that litigation aimed at advancing climate goals has, on balance, been successful, with 58 percent of 369 cases tracked between 2020 to 2021 having outcomes favorable to climate action.
Lea Main-Klingst, a Berlin-based lawyer with the environmental non-profit ClientEarth, said success in pro-climate action cases encompasses more than just legal victories and includes the role they play in educating the public, developing legal thinking and pressuring governments and corporations to change their behavior.
“A loss in court does not necessarily equate to a lost cause,” Main-Klingst said.
ClientEarth, based in the United Kingdom, has emerged as one of the most active legal groups pursuing public interest litigation in the climate realm. Some of its recent cases include a suit against the Belgian National Bank over the institution’s purchasing of bonds from fossil fuel companies, a shareholder lawsuit against Shell’s board of directors over the company’s management of climate-related risks, and a series of suits filed against the Polish government on behalf of private citizens claiming the government violated citizens’ human rights by exceeding its “fair share” of emissions under the Paris Agreement and Polish law.
Main-Klingst said that the group, in deciding which cases to pursue, analyzes relevant laws, evidence, legal procedures and external context like the applicable science and global legal and geopolitical trends.
“The rule of law and climate litigation are inherently connected,” she said. “It’s about ensuring people have the knowledge and tools to take wrongdoers to court, and providing a means to win and uphold the legal protections our planet and all its inhabitants so desperately need.”