Climate Litigation: When Courts Become the Last Line of Defence

Here's a staggering number: as of June 2025, 3,099 climate-related cases have been filed across 55 countries and 24 international or regional courts. That's up from 884 cases in 2017. The cases have more than tripled in under a decade, and they're reshaping the relationship between law, science, and environmental policy in ways nobody quite predicted.

Welcome to climate litigation—where activists, cities, small island nations, and even Swiss pensioners are dragging governments and corporations into court for failing to take climate change seriously. And surprisingly often, they're winning.

The Urgenda Moment (Or: How the Netherlands Got Sued By Its Own Citizens)

The case that changed everything happened in the Netherlands. In 2013, the Urgenda Foundation—a climate activist group—along with 900 Dutch citizens, sued their own government for failing to protect them from climate change.

Their argument? The Dutch government was violating citizens' human rights by not taking sufficient action to reduce emissions. The government's response? Essentially, "that's a policy question, not a legal one—stay in your lane."

The courts disagreed. In 2015, the District Court ordered the government to cut emissions by at least 25% by 2020 compared to 1990 levels. The government appealed. They lost. They appealed again to the Supreme Court. In December 2019, they lost again.

The Supreme Court ruled that under the European Convention on Human Rights, the Netherlands had a positive obligation to take measures to prevent climate change. This wasn't about vague environmental goals—it was about protecting fundamental rights to life and private life from a "real threat."

As Dennis van Berkel, Urgenda's lawyer, told The Wave, even government lawyers thought the case would be overturned at some point. "But I have to be honest, I do think that if you look at how fast the legal development has gone, and how fast there's now recognition internationally – even the IPCC recognising litigation as a form of governance – that has surprised me."

The Global Domino Effect

Urgenda didn't just change Dutch law. It inspired a wave of similar cases worldwide. Sarah Mead, co-director of the Climate Litigation Network, puts it bluntly: "What was a moral imperative ten years ago has become a legal imperative."

Courts in Germany, France, Ireland, South Korea, and Brazil have all delivered rulings compelling governments to strengthen climate targets. Swiss seniors successfully argued in the European Court of Human Rights that their health was threatened by heatwaves worsened by the climate crisis. Australia was found by the UN Human Rights Committee to have violated international human rights law through climate inaction affecting Torres Strait Islanders.

Even corporations aren't safe. In 2021, a Dutch court ordered Shell to reduce its carbon emissions by 45% from 2019 levels by 2030 to comply with the Paris Agreement. That's not a policy suggestion—that's a court order directed at one of the world's largest oil companies.

The Science Is In the Courtroom Now

One of the most significant shifts has been courts' willingness to engage with climate attribution science—research that links specific extreme weather events to greenhouse gas emissions.

Douglas Kysar, Professor at Yale Law School, explains that there are studies using historical corporate documents, mining leases, and securities filings to estimate carbon emissions attributable to particular companies. "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."

And here's the philosophical question keeping oil executives up at night: who bears responsibility for end-use combustion of fossil fuels? The government that authorises and subsidises the industry? The industry itself? Or consumers who purchase and use the fuels?

Courts are increasingly recognising the scientific basis for climate-related claims. As Inger Andersen, Executive Director of UNEP, notes: "Climate litigation has evolved into a powerful global tool for advancing climate action and accountability."

The Corporate Accountability Wave

Unlike early cases focused on forcing governments to adopt better policies, newer litigation targets companies for greenwashing, misleading climate disclosures, and failure to align business practices with stated commitments.

These cases don't require courts to regulate emissions directly. Instead, they use existing legal doctrines—fraud, consumer protection, fiduciary duty—to impose accountability. It's clever lawyering: you're not asking courts to become environmental regulators; you're asking them to enforce laws already on the books.

As research from Enhesa notes, companies with significant emissions, ESG disclosures, or supply chain risks must now monitor liability trends across jurisdictions. "Regulatory authorities and courts are scrutinising ESG claims more closely than ever."

The Separation of Powers Problem

Not everyone thinks courts should be doing this. Critics argue that climate governance involves political, economic, and scientific judgements better suited to legislatures and executives than judges.

The Dutch government made exactly this argument in Urgenda, claiming the lower court had overstepped the "trias politica"—the Dutch separation of powers. The courts rejected it, but the concern hasn't gone away.

As Professor Douglas Kysar acknowledges, there's a "flip side" to litigation: "Access to justice, unfortunately, is often dependent on having resources and access to networks of power." Though he notes that courts are at least open—when you file a lawsuit, defendants must answer and judges must address claims, unlike calling Congress where nobody has to respond.

The Causation Headache

Climate change results from cumulative global emissions over decades. Attributing specific harms to particular actors is extraordinarily difficult.

Courts have adopted different approaches—from probabilistic causation to shared responsibility models. But a 2023 analysis in the Journal of Environmental Law raises uncomfortable questions about Urgenda's actual mitigation impact. The study found that whilst the case achieved compliance with the court-ordered target, "this is a far more modest outcome than one might have expected," and it didn't appear to have "any structural impact on climate policies" or influence other countries' mitigation targets.

Which raises an important question: is the value of climate litigation in the actual emissions reductions, or in shifting norms and creating legal precedents?

The Anti-Climate Litigation Backlash

It's not all victories for climate activists. The UNEP's 2025 report identifies a concerning trend: anti-climate litigation is on the rise. These are lawsuits aimed at deregulating environmental protections or deprioritising ESG considerations in investments.

"Particularly concerning," the report notes, "is the increase in lawsuits against public opposition to high-emitting projects, which target climate advocates, journalists, and civil society organisations." It's weaponising litigation to silence climate action.

What Happens Next?

Andrew Raine, Deputy Director of UNEP's Law Division, told reporters: "We have seen an accelerating wave of climate litigation in national and sub-national court rooms since we started tracking this seven years ago. This year is particularly significant as litigation has also recently started—for the first time—in international courts and tribunals."

The International Court of Justice issued an advisory opinion clarifying states' obligations on climate change. Small island developing states are driving efforts for advisory opinions from various international bodies. Indigenous peoples are increasingly going to court, arguing climate crisis affects their culture, food, water, and survival.

As Kim Bouwer from Durham Law School notes, priorities differ between developed and developing nations. In the US and Europe, litigation focuses on changing environmental policy. In developing countries, people sue to protect livelihoods—focusing on industry impacts on water quality rather than abstract greenhouse gas targets.

The Uncomfortable Reality

Climate litigation is reshaping how we think about environmental responsibility. Courts are being asked to translate scientific consensus into legal obligations, to balance urgent action against democratic processes, and to attribute responsibility for harms caused by countless actors over decades.

Supporters argue courts provide essential checks when political processes fail. Critics warn that litigation risks fragmenting policy and undermining democratic decision-making.

What's undeniable is that climate litigation reflects a growing demand for accountability—and a recognition that when governments and corporations won't act voluntarily, citizens are willing to drag them into court and make them.

Whether this strengthens environmental protection or strains the limits of what judges can reasonably do remains uncertain. But with over 3,000 cases and counting, one thing is clear: climate change isn't just a scientific problem or a policy challenge anymore.

It's a legal battle. And it's being fought in courtrooms around the world, one case at a time.