International Climate Change Rulings Show First Signs of Success
In late July, the International Court of Justice (ICJ) released an advisory opinion that, for the first time in the court’s history, laid down states’ legal obligations to slow climate change.
Among the court’s key findings were that states could be judged legally responsible for the consequences of their fossil fuel production, as well as for failing to regulate the CO2 emissions of private actors in their territory. The opinion also established that governments must effectuate adaptation policies: measures that preemptively tackle the harmful effects of future climate change. These include modifying infrastructure in coastal areas to prepare for rising sea levels, implementing natural disaster warning systems, or developing drought-resistant agriculture.
Just two months after the ICJ decision was published, the Canadian Federal Court employed it to rule on a case filed against the Canadian government.
The plaintiffs in Lho’Imggin v. Canada, who represent the Wet’suwet’en First Nation group, have argued that Canada is violating their constitutional and human rights by failing to cut down on greenhouse gas emissions. In 2020, the Court dismissed the case on the grounds that it lacked a legal basis. Among its objections, it considered climate change to be a political, not a legal, issue. But as of September, it has allowed the plaintiffs to amend their claims in light of the new legal backing provided by the ICJ opinion. This means the case will continue to be debated in court.
According to the judges, the plaintiffs could bolster their case by incorporating international customary law into their arguments. The ICJ established that climate change obligations arise not only from international treaties that states have signed, but also from custom: unwritten law consisting of widely accepted norms that emerge from state practice over time. In Canada, customary international law automatically forms part of domestic law, without the need for Parliament to implement a separate piece of legislation affirming it. This aspect of Canada’s legal system could facilitate the application of international norms in the Lho’Imggin and other environmental cases in the country, allowing citizens to frame the rights owed to them by the state in terms of customary obligations.
The Canadian case offers early hope that, in the face of a rapidly deteriorating climate crisis, the ICJ ruling may be more than merely symbolic. According to the most recent report by the World Meteorological Organization, the average concentration of CO2 in Earth’s atmosphere increased more between 2023 and 2024 than during any other year measured by the organization. The world is on track to surpass 1.5 degrees Celsius of warming above pre-industrial levels, the threshold that scientists have deemed the point of no return for the preservation of the global environment as we know it.
Yet, following the initial excitement over the unprecedented nature of the ICJ opinion, analysts have been hesitant to declare a premature victory for the ruling—and understandably so. The consent-based jurisdiction of international courts and the lack of enforcement mechanisms for their rulings are major limitations on their work. This is all the more true in regard to advisory opinions, which aren’t legally binding. Given these challenges, legal analysts predicted that the ICJ ruling’s true importance would be shown at the domestic level, rather than internationally. The opinion could be used to pressure national governments, or otherwise to reinforce lawyers’ arguments and judges’ decisions against environmentally harmful policies.
Lho’Imggin v. Canada isn’t the only case to suggest that these predictions may come to fruition. Two months prior to the ICJ ruling, the Inter-American Court of Human Rights (IACtHR) published a similar advisory opinion outlining the environmental and human rights duties of states in the Americas. Judges in Colombia have since referenced the opinion in their decision to protect wetland ecosystems from mining. These wetlands, called Páramos, are hubs of biodiversity in the Andes and an important source of potable groundwater. They’re also responsible for capturing and storing tons of carbon that, if disturbed by mining or agricultural activities, would be released into the atmosphere. Thanks to the Inter-American Court’s opinion, the judges were able to grant the ecosystems legal personhood and, by extension, a heightened chance for legal protection. A federal court in southern Brazil has similarly referenced the advisory opinion, leveraging it to temporarily suspend operations at one of the most polluting coal plants in the country.
Despite these successes, a looming question is whether either ruling will succeed in reigning in the United States, one of the world’s foremost fossil fuel emitters.
On the one hand, the ICJ ruling could mitigate the damage of Donald Trump’s withdrawal from the Paris Agreement. The 2015 climate treaty is the most important to date, but the US’s withdrawal in 2020, and then again in 2025, means the country has escaped the text’s legally binding provisions. These include the responsibility to limit global warming to below 1.5 degrees Celsius. Now, because the ICJ opinion asserted that climate change obligations arise from customary law, even states that are not signatories to international agreements must abide by environmental law. This is because, unlike treaty law, customary international law is legally binding on all countries, unless they explicitly and repeatedly object to the norm over time.
On the other hand, recent events suggest that US judges are hesitant to take the ICJ opinion too far in their rulings. In mid-October, a federal court in Montana dismissed a major climate case waged by local youth against the Trump administration, on the grounds that “creating climate policy” was beyond its judicial remit. The judge recognized that the Trump administration’s executive orders would increase emissions and, in the long run, harm young people’s health—but no consideration was made of the international obligations newly reflected in the ICJ or Inter-American Court’s rulings. This decision follows a broader trend in which US courts often refrain from citing international rulings.
If nothing else, some satisfaction can be gleaned from the scientific significance of the two advisory opinions. As evidenced by Donald Trump’s address to the UN General Assembly in September—where he claimed that climate change is a “green scam” and a “con job”—climate change denialism is alive and kicking. Roughly one-third of North Americans aren’t certain whether climate change is caused by human activity, according to the World Economic Forum. Sustainability and conservation policies are also facing deliberate opposition from networks of “counter climate change organizations” operating worldwide, but especially in the US. These groups ground their efforts in skepticism about human-caused climate change, whether its existence or its impacts.
In the context of such post-truth claims, the ICJ and IACtHR opinions are an attempt to call us back to reality: they’ve unequivocally established that human-caused climate change is real, and that it’s here to stay unless states are obliged to take deliberate action against it. What remains to be seen is whether the rulings can continue to succeed towards that end.
Edited by Aubrey Nan
Featured Image: “International Court of Justice at the Hague” by United Nations Photo is licensed under CC BY-NC-ND 2.0.
