Over the last decade, environmental advocates have been increasingly turning to the courts to compel governments to curb climate change.
That movement had a breakthrough moment last week. On 20 May, the United Nations General Assembly formally backed a landmark advisory opinion that said countries have an obligation under international law to reduce the greenhouse gas emissions that are driving the climate crisis.
The resolution passed 141-8 capped a years-long legal effort by a group of low-lying island nations fast losing ground to rising seas.
But why exactly is the UN resolution important and what happens next? Read on to find out.
What does the new UN General Assembly resolution say exactly?
It calls on all 193 UN Member States to comply with their obligations under international law, as identified in a precedent-setting 2025 advisory opinion by the International Court of Justice, the UNs principal judicial organ. That opinion said countries have an obligation under international law to protect the Earth from greenhouse gas emissions. If they dont, and a sufficient causal link to harm is established, they could be required to compensate nations struggling with things like rising seas and extreme weather, the court said. The UN General Assembly resolution is in effect a stamp of approval of the courts opinion.
Is the UN General Assembly decision binding?
No. Like the court opinion it supports, the resolution does not compel countries to reduce their greenhouse gas emissions.
If the resolution isnt legally binding, why does it matter?
There are several reasons. First, its an important sign of the political will that exists to address climate change. The countries that approved the resolution are saying, in effect, that they are onboard with reducing greenhouse gas emissions.
It also re-enforces existing international laws on climate change. Among other things, it said countries must make good on their pledges under the Paris Agreement, which calls on nations to limit global warming to well below 2C and pursue efforts to limit it to 1.5C over pre-industrial levels.
The resolution and the advisory opinion it affirms could also help buttress climate-change-related lawsuits at the national and regional levels. Thousands of such cases are working their way through legal systems around the world. Though, experts expect it may be some time before the resolution influences the outcome of these cases.
Finally, it signals that addressing the climate crisis is not just a political choice it is a legal duty under international law.
What has the reaction been to the resolution?
Many leaders have cheered the decision, with UN Secretary General Antnio Guterres calling it a powerful affirmation of international law, climate justice [and] science.
Vanuatu, the low-lying Pacific island nation that brought the General Assembly resolution forward, said it was deeply significant for vulnerable countries because it confirms that no state is above its obligations to protect people, future generations and our planet.
Why has the resolution been so roundly celebrated?
Because climate change is getting worse by the day. A 2025 UNEP report found the world is likely to shoot past the 1.5C target within the decade. Fast-rising temperatures are throwing the Earths delicate climate systems into disarray, leading to everything from rising seas to more frequent droughts. Experts say humanity must quickly rein in the greenhouse gas emissions that are driving global warming, lest the planet slip into a full-blown climate catastrophe.
Another reason: the resolution represents a victory for multilateralism at a time when international relations are strained.
Are we seeing a rise in climate-related court cases?
Yes. The International Court of Justice opinion was just the tip of the iceberg. As of June 2025, 3,099 climate-change-related lawsuits had been filed around the world, many at the national level, found a UNEP report. In 2017, that number was 884.
Experts say the courts have become an increasingly important tool for everyday people who want to hold businesses and governments accountable for their climate-related commitments. This is especially true for vulnerable groups, like seniors and children, who stand to suffer the most from climate change.
As climate law becomes better defined, experts say the number of successful cases is also likely to increase.
Where did the case before the International Court of Justice begin?
Frustrated by a lack of progress on climate change, a group of Pacific-island law students resolved to use the courts to compel countries to reduce their greenhouse gas emissions.
What began as a class project would be embraced by several nations at risk of being washed away by rising seas. Led by Vanuatu, in 2023 a UN General Assembly resolution was proposed asking for the International Court of Justice to weigh in on the legal responsibilities high-emitting countries bear for climate change. That set the stage for the 2025 advisory opinion and the latest UN General Assembly resolution.
Now that the UN General Assembly resolution has been passed, what happens next?
The resolution calls for the UN-Secretary General to submit a report in 2027 on ways to advance compliance with the obligations identified in the International Court of Justice advisory opinion. Advocates consider this follow-up mechanism key and are hopeful it will lead to recurring compliance checkups. But they caution the resolution alone wont be enough to end the climate crisis. Countries must marshal political will and financing to dramatically cut their greenhouse gas emissions in the coming years if they want to keep the 1.5C goal alive and avoid the worst effects of climate change.
About World Environment Day
World Environment Day, celebrated annually on 5 June, is one of the planet's largest platforms for environmental outreach and is led by the United Nations Environment Programme (UNEP). This year's iteration, hosted by Azerbaijan, will focus on the mushrooming climate crisis. See how you can get involved.
Written by: Andrew Raven
Reviewed by: Angela Kariuki, Andy Raine, Patricia Mbote
