London spent the last week of June under a heat dome. Miki and I were lucky to be staying at the Savile Club in Mayfair, a Grade II listed building that legally cannot bolt an air conditioning unit to its facade, so we sat in the warm and slept in the warmer. On the evening of 25 June we walked to the LSE for the launch of the ninth edition of the Grantham Research Institute’s report on Global Trends in Climate Litigation. There is a particular irony in debating the planet’s overheating while quietly overheating in a protected interior, and it framed the report neatly.
The headline number is 3,600 cases across 62 countries, but the number is not the story. The story is that climate litigation has stopped being an activist tactic and become a form of governance, with courts doing what legislatures and boardrooms have been slow to do: turning climate promises into enforceable duties. State obligations are now treated as a matter of legal duty rather than political preference. Three international advisory opinions, from the International Tribunal for the Law of the Sea, the Inter-American Court of Human Rights, and the International Court of Justice, are already trickling into domestic courtrooms, cited in filings and in judges’ reasoning. Cases are being decided at apex level, beyond appeal, and more than half advance climate action.
There is a pattern in where this energy gathers. The largest surge in the dataset comes from Brazil, where the Federal Public Prosecutor’s Office filed close to two hundred actions against more than six hundred deforesters in late 2024, seeking around 240 million dollars in damages. The timing is hard to read as coincidence. It landed in the run up to Brazil hosting COP30 in Belém, on the edge of the Amazon, with the world’s attention turning to the very forests those cases set out to protect. Preparing to host did not manufacture the lawsuits, but the gravitational pull of a global event concentrated the will to bring them. Litigation rises where awareness rises, and awareness rises fastest where the world gathers and holds a single subject in common focus. The cross border citation between judges, and the advisory opinions seeping into national courts, are the same phenomenon at planetary scale, a shared sense of purpose making accountability contagious.
The corporate turn should focus the mind of every board. Climate washing cases, which challenge the gap between a green claim and the underlying conduct, run at roughly a 65 percent success rate. Courts are reaching into private law as well as public duty, with a Swiss court applying human rights reasoning developed against a government to the obligations of a cement company. State owned enterprises and financial institutions have joined the list of defendants, and the newest subject matter reads like a technology briefing, with data centres and the footprint of artificial intelligence now in scope. For anyone in industry, this is no longer somebody else’s problem.
Nowhere is the shift clearer than in the United Kingdom after Finch. Two years ago the Supreme Court ruled in Finch v Surrey County Council that a project’s downstream emissions, produced when the oil is eventually burned, must be assessed before permission is granted. Consents were quashed or thrown into doubt for drilling in Lincolnshire, a coal mine in Cumbria, and the Rosebank and Jackdaw fields. The principle is spreading to new sectors, including data centres and intensive farming, often without a case reaching court. A strong precedent lets others win by pointing at it.
The same day as the launch, a French court decided the long running case against TotalEnergies, ordering the company to supplement its plan within six months to add downstream risk mapping while declining to dictate its transition strategy. That is the pattern in a sentence. Courts will insist you map, disclose and tell the truth about your exposure, but will not, for now, run your strategy for you. The flip side is just as instructive. The Lower Thames Crossing, the country’s second largest infrastructure project, became the first to commit to net zero, its chief executive saying plainly that he chose it to avoid being sued, at a cost of zero to two percent above budget. It is the only large project of its kind not facing a climate challenge, because litigation risk was priced in as a design parameter rather than handled later as a public relations problem.
Strip away the case law and what increased legal action really delivers is accountability. For most of the past decade, climate commitments were policed by soft mechanisms: an annual report, an investor letter, a campaign group’s statement, the occasional awkward headline. Those rely on goodwill and attention, both of which fade. Litigation does not. It attaches a consequence to the distance between what an organisation promises and what it does, on a timetable it does not control, running upward to governments, sideways to companies through private law, and outward to the financiers and state owned enterprises that used to sit comfortably behind their clients. Even cases that lose extract a price, by forcing disclosure and putting the next board on notice. Accountability has stopped being voluntary.
This is where the legal and the reputational collapse into one another, which is the territory this newsletter cares about most. Every net zero pledge, every sustainability claim, every glossy ESG report is now a document that could be read back to you as evidence. Green hushing, going quiet on sustainability to avoid an accusation of greenwashing, is a tell rather than a strategy. Saying less does not protect you, and saying more does not either. Doing what you said you would do is the entire defence.
For readers across the Gulf, 81 percent of these cases still sit in the global north, with the United States far in front, but the direction of travel runs one way. The International Court of Justice has clarified that being a developing economy does not erase the obligation to mitigate, which carries real implications for jurisdictions watching from a distance. The question for any organisation is no longer whether its climate claims will attract scrutiny, but whether they would survive it. Sweating through a London heatwave in a building legally forbidden from cooling itself, the lesson felt unusually physical. The gap between what we promise and how we live is closing, in courtrooms and elsewhere, whether the room is ready or not.
THE SIGNAL
State obligations to act on climate change are increasingly being consolidated as a matter of legal duty, not merely political choice.
Global Trends in Climate Litigation: 2026 Snapshot, Grantham Research Institute, London School of Economics
THE QUESTION
Every climate commitment your organisation has published is now a document that could be read back to you in a courtroom. Would yours survive the reading?