Efforts to enshrine the principle of polluter pays in the climate change challenge were boosted on Wednesday in a landmark International Court of Justice ruling on the impact of a changing planet.
A ruling from the UN's principal court said “the urgent and existential threat posed by climate change” created a legal obligation on states to take action.
Ultimately that means countries harmed by climate change could be entitled to reparations. The legal and political weight of the world court is likely to bear heavily on future climate litigation.
“Greenhouse gas emissions are unequivocally caused by human activities which are not territorially limited,” judge Yuji Iwasawa said.
The court said countries have an obligation to take binding measures to comply to climate treaties and that industrialised nations have an obligation to take the lead in combating climate change.
The two questions the UN General Assembly asked the judges to consider were: what are countries’ obligations under international law to protect the climate from greenhouse gas emissions; and what are the legal consequences for countries that harm the climate system?
“The advisory opinion is probably the most consequential in the history of the court because it clarifies international law obligations to avoid catastrophic harm that would imperil the survival of humankind,” said Payam Akhavan, an international law professor.
Outside the court at the Peace Palace in The Hague, about 100 demonstrators waved flags and posters bearing slogans including “no more delay, climate justice today”.
They were joined by Vanuatu's Climate Change Minister Ralph Regenvanu, whose South Pacific nation − composed of more than 80 islands − is vulnerable to rising sea levels.
In two weeks of hearings last December at the ICJ, also known as the World Court, Mr Akhavan represented low-lying, small island states that face an existential threat from rising sea levels. In all, over a hundred states and international organisations gave their views.
Wealthy countries told the judges that existing climate treaties, including the 2015 Paris Agreement, which are largely non-binding, should be the basis for deciding their responsibilities.
Under the 2015 Paris Agreement, countries pledged to try to keep global temperature rises to well within 2°C above pre-industrial levels.
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.
The biggest set of interventions ever heard at the ICJ has excited experts predicting a major impact on laws around the world. More than 100 nations and groups gave oral statements that pitted major wealthy economies against smaller, less developed states most at the mercy of a warming planet.
The ICJ heard warnings not to deliver a fresh legal blueprint for climate change, arguing the existing United Nations Framework Convention on Climate Change framework − a parent treaty of the Paris Agreement − was comprehensive.
The US, which has withdrawn from the Paris Agreement, said the UNFCCC contained legal provisions on climate change and urged the court to uphold this regime.
But smaller states said this framework was inadequate to mitigate climate change
“I think it will be a game-changer for the whole climate discourse we're going through,” said Mr Regenvanu. Experts agreed that the ruling gave the low-lying states new legal avenues for redress.
“For the first time, the world’s highest court has made clear that states have a legal duty not only to prevent climate harm — but to fully repair it," said Joana Setzer, associate fellow at the Grantham Research Institute on Climate Change and the Environment at the London School of Economics and Political Science. "The ICJ’s advisory opinion affirms that states responsible for climate harm must provide full reparation to injured states, reinforcing the legal basis for climate justice."
Vanuatu spearheaded the push for a court opinion amid growing frustration at sluggish progress in UN climate negotiations.
“We've been going through this for 30 years … It'll shift the narrative, which is what we need to have,” Mr Regenvanu said.
