Climate protection is a human right, International Court of Justice states

Judges stated that states must act in accordance with the latest climate science, in line with the international goal to limit warming to 1.5 °C, as set out in the 2015 Paris Agreement. The court described the climate system as a vital part of the environment that must be protected for the benefit of present and future generations. Though the opinion is non-binding, it carries significant legal and political weight and may shape future climate litigation and treaty negotiations.

It comes amid increasing efforts to hold governments accountable for climate change through legal avenues. In a separate landmark ruling last year, the European Court of Human Rights (ECHR) ruled in favour of a group of older Swiss women who argued their government’s insufficient action on climate change exposed them to deadly heatwaves.

The Strasbourg court found that inadequate climate policy can amount to a violation of human rights, setting a precedent for similar cases across Europe.

At the international level, discussions are underway to criminalise large-scale environmental destruction.

Last year, the International Criminal Court (ICC) began formal discussions on recognising ecocide as a new crime under the Rome Statute.

The proposed definition of ecocide encompasses acts committed with knowledge that they are likely to cause severe and widespread, or long-term, damage to the environment.

If adopted, this would allow the court to prosecute individuals, including corporate executives and government leaders, for environmental destruction such as large-scale oil spills or deforestation.

The ecocide proposal, backed by several Pacific Island nations, faces legal hurdles as ecocide is not yet part of customary international law or recognised as a core international crime.

Nevertheless, climate litigation is gaining momentum, driven in part by advances in climate attribution science, which now enable the connection of specific weather events and deaths to human-driven climate change.

Researchers recently estimated that the heatwave in southern England in June this year caused 263 deaths in London, 171 of which were attributed to the increased temperatures linked to climate change.

Legal challenges are increasingly drawing on this science. Friends of the Earth recently announced it will take its case against the UK Government’s climate adaptation plan to the ECHR.

The group argues that the Government’s failure to prepare adequately for climate impacts breaches the rights of people in the UK, especially those most vulnerable to heat and flooding. The UK High Court previously ruled the Government’s adaptation plan lawful.

The ICJ’s opinion adds a new layer of legal clarity on what governments are required to do to prevent climate harm. While the court cannot enforce its ruling, it reinforces the growing view that states may be held accountable for climate inaction under international law.

ICJ reaction: ‘A rocket boost for climate justice’

Reacting to the ICJ’s opinion decision, the Grantham Research Institute on Climate Change and the Environment’s Noah Walker-Crawford said: “The ICJ’s advisory opinion brings the weight of international law behind what climate science has shown for decades. By grounding states’ obligations in scientific consensus and human rights law, the Court affirms that governments must not only reduce their own emissions, but also regulate companies to do the same.

“This creates a powerful foundation for future claims to hold both states and major emitters accountable.”

Power Shift Africa’s director Mohamed Adow said: “This ruling is a rocket boost for climate justice. The ICJ has confirmed what Africa has long demanded: that rich nations must be held accountable for the damage their emissions have caused.

“For a continent like Africa – least responsible but most affected – this decision is a lifeline. It strengthens our call for reparations, debt relief, and real climate finance – not loans that deepen poverty… the law now backs our moral case.”

“The era of polluters hiding behind vague promises is over.”

Greenpeace International’s legal counsel Danilo Garrido said: “This is the start of a new era of climate accountability at a global level. The ICJ advisory opinion marks a turning point for climate justice, as it has clarified, once and for all, the international climate obligations of states, and most importantly, the consequences for breaches of these obligations.