As the Trump administration takes an axe to national climate policy, a landmark advisory opinion issued in late July by the world’s top court is expected to encourage and shape legal cases on climate change in the United States which could contribute to holding big polluters accountable.

The Hague-based International Court of Justice (ICJ) clarified for the first time last week that states have a responsibility to protect the climate system from greenhouse gas emissions and prevent “significant harm” to the climate and environment so that people can enjoy their human rights.

Although the US has a patchy record of complying with ICJ rulings and is pulling out of the Paris Agreement – the main global pact for reducing emissions in line with limiting warming to 1.5C – experts told Climate Home News that branches of the US government and US-based companies could still be hit by a surge of climate cases referencing the legal tools in the ICJ advisory opinion. 

“This ruling adds legal momentum to the fight for climate justice in the US and around the globe, and will serve as a springboard for lawyers, activists and policymakers on the frontlines seeking remedy for climate harm,” said Erika Lennon, a senior attorney at the Center for International Environmental Law (CIEL).

Among the ICJ pronouncements, its judges said government activities that support the expansion of fossil fuels – including by private actors – may represent an “internationally wrongful act”. They also said that historically large polluters could be liable to pay reparations for the damage caused by their contributions to the climate crisis.

In US courts, the advisory opinion “will strengthen the claims made by climate activists suing the federal and state governments, and also strengthen the claims of states and cities that are suing fossil fuel companies to claim damages”, said Ashfaq Khalfan, director of climate justice at Oxfam America.

Among recent cases, 22 youth activists filed a lawsuit in Montana against Trump’s executive orders on energy, arguing that these will increase the use of fossil fuels and slow down clean energy, violating their rights to life and liberty. In another case, youth activists in California sued the Environmental Protection Agency (EPA) for allowing high levels of climate pollution. Khalfan said plaintiffs in these cases could point to the government’s failure to protect their rights based on the ICJ ruling.

Trump indifferent to climate law

In the week after the ICJ landmark ruling, the EPA announced it would repeal a key scientific declaration from 2009 which states that greenhouse gases put human health at risk. The so-called “endangerment finding” has served as a basis for climate regulation in the US.

The EPA’s move shows the “stark” contrast between the international community’s stance on climate action and conversations at the federal level in the US, said Carly Phillips, a scientist with the Science Hub for Climate Litigation at the Union of Concerned Scientists (UCS). 

Given this and many other Trump-led efforts to thwart US climate action, Michael Gerrard, a climate law professor at Columbia Law School, said the Republican president’s administration “will certainly pay no attention” to the ICJ ruling. 

Gerrard added that courts in the US “tend to not pay much attention to the decisions of international tribunals in matters such as this”. The US withdrew from recognising the ICJ’s compulsory jurisdiction in 1986. 

In response to the court’s opinion on states’ responsibilities on climate change, White House spokeswoman Taylor Rogers told Reuters: “As always, President Trump and the entire administration is committed to putting America first and prioritising the interests of everyday Americans.” 

Margaretha Wewerinke-Singh, who acted as Vanuatu’s lawyer in the ICJ case triggered by the island nation, told Climate Home that governments could potentially initiate counter-measures like economic sanctions or trade restrictions against others that don’t comply with the ruling. “So that puts the US or any states that ignores their obligations in a very vulnerable position,” she added.

Impossible to ignore?

Phillips of the UCS argued it would be impossible for the US government to ignore the ICJ opinion entirely. “Regardless of what their feelings are, they can’t dismiss this ruling just because they don’t like it,” she told Climate Home. “[It] has shown that countries around the world are bound by international law to address climate change.”

She added that the opinion provides “so much important context” for US courts that are already grappling with a lot of climate-related lawsuits, as well as “really strong moral clarity” around the responsibilities of states. 

“While the federal government in the United States is quite obviously not co