The UN’s willingness to tackle the climate crisis in a fair and legal way will be tested next week during a critical vote of the UN general assembly in New York.

Every member state is being asked to back a series of landmark findings on climate justice from the international court of justice (ICJ) as part of a new political resolution. If passed, it will mean governments recognise they have a legal responsibility to cut their greenhouse gas emissions, including tackling fossil fuels.

The ICJ’s advisory opinion, published last year following a series of hearings in the Hague, had been requested by an unprecedented 132 states without opposition in 2023. It was hailed as a “historic win” for small island states.

The Pacific island nation of Vanuatu has since been leading a group of states to draft a resolution that welcomes the opinion and tries to help it make a difference on the ground. Ahead of the UN vote on 20 May, it is seeking support from as many other nations as possible.

At a UN briefing earlier this month, the Vanuatu climate minister, Ralph Regenvanu, described the UN’s initial resolution as “a collective act of multilateral confidence that law can help steer us through the climate crisis” that the court answered unanimously. “That unanimity is a gift to the membership. It gives us legal clarity and it gives us something precious in the UN; a common reference point.”

Regenvanu wants the resolution to get the “broadest possible support”, at least matching the 132 co-sponsors of the previous one.

The text of the resolution has changed significantly since an initial draft circulated in February. Calls for a “rapid, just and quantified phase‑out of fossil fuel production and use”, for example, were replaced with an urge to transition away. An original aim to set up an international register of damage, loss or injury was dropped altogether.

Some major changes were the result of pressure from the US, which has lobbied to drop the resolution altogether. But Vanuatu’s climate justice envoy, Lee-Ann Sackett, who led the negotiations, said many states raised concerns or had comments, so significant effort was made to keep the text both “meaningful and unifying”.

“Where delegations asked for reassurance we made it explicit,” she said. “Where delegations asked for restraint, we built in safeguards.”

The final text, published at the start of the month, now clearly states that the UNFCCC and the Paris agreement are the primary international intergovernmental forums for negotiating a global response to climate change. Regenvanu stressed that it does not adjudicate disputes or attribute responsibility to any particular state. Nor does it create new obligations or prejudice legal positions.

Despite the changes, Regenvanu said it was “not a resolution that simply files the opinion away. It calls on all states to comply with their existing obligations as established by the court.” It is also intended to help member states think through how to implement these obligations.

The court’s advisory opinion is already being used in climate litigation around the world and judges are starting to reference it in their climate-related rulings.

But it has proved more intractable as a diplomatic lever. It failed to make a mark at last year’s UNFCCC climate talks in Belem; Saudi Arabia called its inclusion in final texts a “red, red line”.

The opinion was more evident at the inaugural fossil fuel conference in Santa Marta, Colombia, where Regenvanu told state delegates that they were “frontrunners” in doing what is both legally and scientifically required. “That is why theICJ’s landmark advisory opinion on climate change considers international cooperation indispensable.”

More broadly, the resolution is being seen as a key test for the credibility of the international legal system.

Sackett said there was close engagement from state delegations that do not usually intervene on climate texts “because they recognise that this is also about the authority of the court, the integrity of the UN system and how we translate legal clarification into multilateral cooperation”.

Tania Romualdo, the permanent representative of Cape Verde to the UN representing the Alliance of Small Island States (AOSIS), said the importance of the resolution extends beyond the text itself.

For small island developing states, she said, “this is about the affirmation and protection of our territories, sovereignty and fundamental rights of our populations. This process has not been easy. There have been many sacrifices along the way. These are not easy compromises but they reflect the reality of negotiation.”