Media reaction
World's highest court confirms countries must act to avert climate catastrophe in a "once-in-a-generation" legal decision
23 July 2025
The International Court of Justice (ICJ) has published a landmark legal decision today – unanimously confirming that big polluters must scale up their efforts to address climate change under international law.
This landmark outcome is the result of a multi-year campaign led by communities enduring unprecedented sea level rise, storm surges and extreme heat, amongst many other climate impacts. [1]
High-emitting states, alongside the companies they are obliged to regulate, are officially on notice: polluting with abandon comes with a high moral and legal price.
ClientEarth lawyer Lea Main-Klingst said:
“Today’s decision is a once-in-a-generation moment for all of us fighting for climate justice.
“The world’s highest court has affirmed what millions of people all over the world have said time and time again: climate change threatens our very survival - and high-emitting states can and must be held accountable for the damage they’ve done.
“The judges have also sent a clear message to corporate and financial giants: the age of producing and bankrolling fossil fuels with abandon is over.”
In its decision, the judges of the ICJ said:
· If governments and parliaments fail to curb the production and consumption of fossil fuels, approve fossil fuel projects and roll out public money for fossil fuels, they could be in breach of international law.
· Historical emitters (i.e. countries who have burned the most fossil fuels for the longest periods of time) have a greater responsibility to address the climate crisis and limit global warming to 1.5 C.
· Countries are bound by international law to regulate companies and businesses’ climate impacts.
· A healthy environment is the foundation for human life and human rights protected by international law.
· There is a potential route to reparations for states enduring the worst of the climate crisis to hold historical emitters to account.
On what this means for environmental litigation and upcoming climate negotiations in Brazil, ClientEarth lawyer Lea Main-Klingst said:
“This new-found clarity will equip judges with definitive guidance that will likely shape climate cases for decades to come.
“And outside the courtroom, this result is a powerful advocacy tool. Each and every one of us can use this decision to demand our governments and parliaments take more ambitious action on climate change to comply with both the Paris Agreement and other applicable international laws.
“We are immensely grateful to the Pacific Island Students Fighting Climate Change (PISFCC) for bringing these vital legal questions from the classroom all the way to the International Court of Justice – and to all those who supported their tireless work.
“It’s now up to civil society and legal advocates everywhere to pick up this new tool and use it, including both in the lead-up to and during upcoming climate negotiations at COP30.
“And closer to home – with the wind of this decision behind them, national governments and parliaments have an even greater responsibility to implement strong, ambitious plans to avert the worst of the climate crisis and protect our human rights.”
ENDS
Notes to editors:
The full decision from the ICJ is available here.
[1] The campaign to ask the International Court of Justice to address the impacts of climate change began with the Pacific Islands Students Fighting Climate Change (PISFCC) campaign that began in a classroom in Fiji.
They decided the court should confirm that states had an obligation to address climate change under international law. The government of Vanuatu agreed and, together with 18 ICJ Champions Nations and 132 countries, formally requested through the UN General Assembly an official legal opinion from the ICJ on climate change. The request passed by consensus at the UN General Assembly in March 2023.
2024 and 2025 international legal developments
The past two years have seen a number of landmark legal decisions and opinions when it came to what states must do on climate change under international law:
· Just this month, the Inter-American Court of Human Rights issued its own advisory opinion on what states must do to address climate change, which was heralded as ushering in a “new era of climate justice” as the court unequivocally said countries must do more to address the impacts of climate change.
· The European Court of Human Rights (ECtHR) ruled in April 2024 that Switzerland must take more ambitious climate action to protect the rights of a group of senior Swiss women – a ruling that is binding on all 46 signatory Parties of the Council of Europe and sets a legal expectation worldwide.
· The International Tribunal for the Law of the Sea (ITLOS) – the world’s authority on the Law of the Sea – issued its own advisory opinion in May 2024 and said that states must reduce their greenhouse gas emissions to comply with the UN Convention on the Law of the Sea and specifically its core obligation to protect and preserve the marine environment from pollution.
· In Hawaii, the state agreed in June 2024 to decarbonise its transport system in a settlement with 13 young people. The youth-led lawsuit argued that Hawaii was violating their rights under its constitution by prioritising infrastructure (i.e. highway construction) that would lock-in greenhouse gas-emitting transport.
· In August 2024, South Korea’s Constitutional Court ruled that the country’s climate plan failed to protect people’s human rights – particularly those of younger generations.
About ClientEarth
ClientEarth is a non-profit organisation that uses the law to create systemic change that protects the Earth for – and with – its inhabitants. We are tackling climate change, protecting nature and stopping pollution, with partners and citizens around the globe. We hold industry and governments to account and defend everyone’s right to a healthy world. ClientEarth teams in Europe, Asia and the USA work to shape, implement and enforce the law, to build a future for our planet in which people and nature can thrive together.