Cease and desist: Climate science is now the law

• The science on climate change has long been settled. Now the law is, too. On Wednesday, the International Court of Justice, the judicial branch of the United Nations, recognised for the first time that there is no way to solve the climate crisis or atone for its devastating consequences without confronting its root cause: the burning of fossil fuels.

Back in 2023, the South Pacific archipelago nation of Vanuatu and other climate-vulnerable countries, with the help of Pacific Island students, secured a United Nations resolution asking the International Court of Justice to clarify what existing international law requires governments to do about climate change and what legal consequences they face if their failure to uphold the law causes serious harm. The court’s conclusion comes on the heels of two other international advisory opinions on climate change and a growing number of national judgments.

Earlier this month, the Inter-American Court of Human Rights declared that the climate crisis is a human rights emergency, triggering human rights obligations for nations and businesses. Its sweeping opinion acknowledged the outsize role the oil and gas sector plays in generating planet-warming emissions, and emphasised the duty of governments to regulate and control these polluters. A 2024 climate opinion from the International Tribunal for the Law of the Sea likewise affirmed that greenhouse gas emissions pollute the marine environment and that countries must prevent environmental harm that affects other countries, whether it comes from public actors or private companies.

The ICJ’s unanimous opinion reinforced these conclusions and broadened their reach, stating that countries must protect citizens from the “urgent and existential threat” of climate change. When a country fails to curb greenhouse gas emissions — whether by producing or consuming fossil fuels, approving new exploration to find them or subsidising the industry — it may be held liable for “an internationally wrongful act,” the court’s 15 judges said.

This makes it much harder for any government or company to say that rules don’t apply to them or they don’t have to act. Read together, these three landmark legal rulings leave no doubt that continuing fossil fuel production and use, let alone expanding it, violates the law. It is a cease-and-desist notice to fossil fuel producers.

Governments, industry and scientists have known for decades that fossil fuels are the principal cause of climate change. Oil, gas and coal account for nearly 90% of carbon dioxide emissions, and science shows that it is impossible to prevent a rise in global temperatures unless new fossil fuel projects are stopped and existing ones shut down. But fossil fuel companies have systematically delayed climate action, first by denying the science, then by derailing the most aggressive regulations and goals with intense lobbying.

Far from putting the brakes on climate-heating emissions, many of the biggest fossil fuel producers are expanding investments in oil and gas, and some, including the US, are even trying to crush the cleaner alternatives such as solar and wind.

The case before the ICJ is part of a growing global movement that is turning to the courts to hold polluters accountable. From the lawsuits brought by a Belgian farmer against the French oil giant TotalEnergies and Indonesian villagers asking a Swiss cement company to pay climate damages, to the dozens of cities and states across the US that have accused the fossil fuel industry of climate deception and harm, a new wave of plaintiffs is edging closer to making polluters pay.

Leading fossil fuel-producing nations, such as the US and Saudi Arabia, will probably argue that this ICJ opinion is unenforceable and thus inconsequential. But no country is exempt from the obligations the court laid out. Their duties to prevent and remedy climate harm are rooted in multiple sources of law, including principles and treaties with which all countries must comply.

The ICJ’s determination of what those laws require in relation to climate change clarifies what countries must do to protect the climate and the liability they face if they don’t. The reasoning may surface in lawyers’ briefs and judges’ decisions in many of the hundreds of pending climate cases around the world, including a growing number of lawsuits against fossil fuel companies. It could bolster the justifications for climate superfund laws such as those adopted in Vermont and New York that seek to make polluters pay their fair share for climate impacts, rather than leaving the public to foot the bill.

Some governments face lawsuits from companies seeking compensation for climate measures that restrict or shut down their oil, gas and coal investment projects, for instance, cases pending in Germany and the Netherlands. The new ruling could strengthen their ability to defend themselves.

The court also said that nations have an obligation under the Paris agreement to limit global warming to 1.5 degrees Celsius since the start of the Industrial Revolution and to ensure that their national climate plans are actually capable of sticking to it. For too long, countries have hidden behind the notion that their climate mitigation measures are voluntary.

No ruling on its own can bring the fossil fuel era to its end; rather, it is the people who use it — in litigation, legislation and negotiations worldwide — who will give it teeth and make its conclusions impossible to ignore.

Now that the court has spoken, the real work begins. Fossil fuel polluters must hear the message loud and clear, in courtrooms and in boardrooms, from town halls to city streets: Cease and desist, pay up and phase out. Unless we hold big polluters to account, the unjust toll of climate change will only mount.

The New York Times