ICJ advisory opinion on global climate action is a game changer

SINGAPORE - The International Court of Justice (ICJ) has put polluting governments and companies on notice: They are legally responsible for the climate-linked damage their carbon emissions are inflicting on the planet and vulnerable nations.

In a landmark advisory opinion on July 23, the ICJ said all countries have significant legal responsibilities to prevent further climate harm by slashing their climate pollution rapidly. Countries are also responsible for regulating companies and their actions.

Polluters could be liable for damage caused by past and current emissions. 

States’ legal responsibilities for carbon pollution and its impacts are not just confined to climate treaties, such as the Paris Agreement, but also under the law of the sea convention, human rights treaties, other binding instruments and general principles of international law, the ICJ said.

The opinion is likely to be a significant boost for climate litigation and could lead to stronger carbon-cutting policies by governments and strengthen flagging United Nations climate negotiations, long held back by the lack of political will to ramp up climate action.

Fossil fuel states – and companies – could now be especially at risk of litigation.

“The court left no legal shelter for business as usual,” said Mr Vishal Prasad, director of the Pacific Islands Students Fighting Climate Change, a group that was instrumental in bringing the case before the ICJ.

“It made clear that the status quo is incompatible with states’ legal obligations under international law – a finding that will inform climate litigation and advocacy for years to come,” he said in a statement.

The outcome is a victory for Vanuatu.

The Pacific island nation, which has been repeatedly hit by cyclones and affected by rising sea levels, championed a 2019 initiative by its law students to seek legal avenues to boost global climate action.

Vanuatu’s campaign led to more than

130 nations, including Singapore, supporting a UN General Assembly resolution in 2023

for the ICJ to deliberate questions on state obligations with respect to climate change.

During hearings in late 2024, nearly 100 nations, including Singapore, gave testimony to the court.

“(The ICJ opinion is a) very important course correction in this critically important time,” Mr Ralph Regenvanu, Vanuatu’s minister for climate change, told reporters after the opinion was read out, adding that the opinion was far better than he had hoped for.

Associate Professor Lowell Bautista, director of the academic programme in the School of Law at Western Sydney University, said: “In (issuing its opinion), the court elevates climate protection from a matter of political discretion to one of binding legal duty.”

Legal experts and climate campaigners also say the decision is a milestone because it directly challenges the notion that big polluting states and fossil fuel companies cannot be held responsible for the impacts of their greenhouse gas pollution or weak climate policies.

It is the first time the ICJ has addressed states’ obligations regarding climate change under existing laws. It has come as the impacts of global warming – from extreme floods and storms, to wildfires and rising sea levels – are worsening and affecting the poorest and most vulnerable nations the most.

Ripple effects

“The ruling by the ICJ is a watershed moment in the fight for climate justice and will likely have ripple effects in courtrooms, boardrooms, legislative halls and international negotiations around the world,” said Ms Erika Lennon, senior attorney for the Centre for International Environmental Law.

“The powerful advisory opinion made clear that all states have a legal duty under multiple sources of international law to protect the climate and preserve our collective future,” she told The Straits Times.

In a unanimous opinion, the court’s 15 judges emphasised that longstanding duties to prevent environmental harm, which include preventing climate damage and protecting human rights, mean that states must take action to address the drivers of climate change.

The court said failure of a state to take appropriate action to protect the climate system from greenhouse gas emissions – such as through fossil fuel production and consumption, as well as granting exploration licences and subsidies – may constitute an internationally wrongful act that is attributable to that state.

This finding could be troubling for big fossil fuel producers such as Australia, one of the world’s top exporters of coal and gas. And it could lead to a revision of duty-of-care protections by governments.

Earlier in July, Australia’s Federal Court rejected a landmark case brought by Torres Strait Islanders who argued the government had a duty to protect them from climate change impacts.

The court found the government was not legally obligated to shield the islands from climate change, despite acknowledging the climate threat and the vulnerability of the Torres Strait communities to said threat.

But, should the islanders appeal, a superior court could revisit the government’s obligations in light of the ICJ ruling, legal experts in Australia said on July 24.

The ICJ opinion provides a critical reference for lawyers and judges to inform cases filed and rulings issued both in domestic and international courts, and indicates to states and private actors alike what they must do to curb the climate crisis, Ms Lennon said.

“No country is exempt from the obligations the court laid out. The duties to prevent and remedy climate harm are rooted in multiple sources of law, including fundamental legal principles and treaties with which all countries must comply,” Ms Lennon noted.

National climate policies

The ICJ judges also took aim at weak climate policies in a decision that could strengthen the hands of nations calling for stronger climate action at UN climate talks.

The judges made clear that states’ climate plans, called nationally determined contributions (NDCs) under the Paris Agreement, must be of the highest ambition and aimed to limit warming to 1.5 deg C above pre-industrial levels, a key limit backed by scientific research.

Under the Paris pact, nations must submit updated and more ambitious NDCs every five years. In 2025, states must submit NDCs up till 2035. So far, only about 30 states, including Singapore, out of nearly 200, have done so.

“Given the assessments of NDCs to date, many states may, in fact, have to update their climate policies and then implement them. The court was clear – merely having an NDC is not enough,” said Ms Lennon.

The court noted that states do not have unlimited discretion in defining their NDCs but are required to act with due diligence to ensure that their NDCs are capable, when considered alongside others, of keeping global temperature rise to 1.5 deg C, she added.

Moral weight

Analysts say the ICJ opinion, while not legally binding, carries strong moral authority and will inform how national and international courts interpret laws, including those regarding negligence and harm caused to other states.

It also raises the very real possibility of reparations to poorer nations for climate harms.

The ICJ made clear that states have to regulate private actors – companies – and ensure that their activities are not causing climate damage.

“Additionally, the court stated that a breach of these duties could trigger legal consequences, including financial compensation, for example for loss and damage, as well as non-financial reparations and cessation of harm,” said Ms Lennon.

The court also confirmed that harm from climate impacts could be established and scientifically attributed to specific polluter states whose acts or omissions resulted in significant harm.

Climate litigation

Legal cases by citizens, rights groups and others targeting companies and governments have grown strongly in recent years.

At least 226 new climate cases were filed in 2024, bringing the total number of cases filed between 1986 and 2024 to 2,967 across nearly 60 countries, according to the Grantham Research Institute on Climate Change and the Environment at the London School of Economics and Political Science.

Most of the cases are in the United States, Europe and Australia, but that is changing, with cases growing in developing nations, including much of Asia.

Around 20 per cent of climate cases filed in 2024 targeted companies, or their directors and officers.

The ICJ’s strong opinion is likely to increase litigation in international tribunals and forums, said Dr Joana Setzer, Grantham Research Institute’s associate professor of climate governance and climate litigation.

“The opinion could also shape judicial understandings of climate change, particularly in jurisdictions where international law and norms can influence domestic ‘standards of care’ in the context of assessing state and non-state actor responsibility to address climate change,” she told ST.

And for Asia?

The opinion gives solid legal ground for vulnerable communities to bring claims not only against states for climate inaction but also against corporations that seek to expand fossil fuel extraction and subsidies, on human rights grounds for irreversible climate harm – as Ms Nicole Ponce, an environmental and human rights lawyer-advocate from the Philippines with the World’s Youth for Climate Justice campaign group, told ST.

Observers said that for now, governments, companies and lawyers will be closely studying the 133-page opinion for next steps.

Vanuatuan minister Regenvanu, a key figure in bringing the case before the ICJ, said one quick result could be the strengthening of national climate plans ahead of the UN’s upcoming COP30 climate conference in Brazil in November.

“We hope to see many more NDCs submitted, and even those that have already been submitted, revised and resubmitted to ensure they are at the standards required by these legal obligations,” he said.