The United Nations' highest court has underscored "the urgent and existential threat posed by climate change" as it delivered its ruling on the legal obligations of states to take action.
Wednesday’s non-binding opinion by the International Court of Justice, also known as the World Court, is expected to shape the course of future climate action globally.
Ahead of the ruling, supporters of climate action gathered outside the ICJ, chanting: "What do we want? Climate justice! When do we want it? Now!"
Although non-binding, the deliberation of the 15 judges of the ICJ in The Hague will nonetheless carry legal and political weight, and future climate cases are unlikely to ignore it, legal experts say.
"It is so important; it could be one of the most consequential legal rulings of our times because of the scope of the issues it touches, which go to the very heart of climate justice," said Joie Chowdhury, senior attorney at the Centre for International Environmental Law.
The two questions the UN General Assembly asked the judges to consider were: what are states’ obligations under international law to protect the climate from greenhouse gas emissions; and what are the legal consequences for states that harm the climate system?
In two weeks of hearings last December at the ICJ, wealthy nations of the Global North told the judges that existing climate treaties, including the 2015 Paris Agreement — which are largely non-binding — should form the basis for determining their responsibilities.
Developing nations and small island states argued for stronger measures, in some cases legally binding, to curb emissions and for the biggest emitters of climate-warming greenhouse gases to provide financial aid.
Paris Agreement
In 2015, at the conclusion of UN talks in Paris, more than 190 countries committed to pursuing efforts to limit global warming to 1.5 degrees Celsius (2.7 degrees Fahrenheit).
The agreement has failed to curb the rise in global greenhouse gas emissions.
Late last year, in the most recent "Emissions Gap Report", which assesses countries' climate pledges against what is required, the UN said current climate policies would lead to global warming of more than 3°C (5.4°F) above pre-industrial levels by 2100.
As campaigners seek to hold companies and governments to account, climate-related litigation has surged, with nearly 3,000 cases filed across almost 60 countries, according to June figures from London’s Grantham Research Institute on Climate Change and the Environment.
Thus far, results have been mixed.
A German court in May dismissed a case brought by a Peruvian farmer against German energy giant RWE, but his lawyers and environmentalists said the case — which dragged on for a decade — was nonetheless a victory for climate litigation that could inspire similar lawsuits.
Earlier this month, the Inter-American Court of Human Rights, which holds jurisdiction over 20 Latin American and Caribbean countries, said in another advisory opinion that its members must cooperate to tackle climate crisis.
Campaigners say Wednesday’s court opinion should mark a turning point, even if the ruling itself is advisory.
The ruling could also make it easier for states to hold others accountable over climate issues such as pollution or emissions.
"The court can affirm that climate inaction, especially by major emitters, is not merely a policy failure but a breach of international law," said Fijian Vishal Prasad, one of the law students who lobbied the government of Vanuatu in the South Pacific to bring the case before the ICJ.
Although it is theoretically possible to disregard an ICJ ruling, legal experts say countries are typically reluctant to do so.
"This opinion is applying binding international law, which countries have already committed to," said Chowdhury.
