The Verdict Is In: To Comply with the Law, COP30 Must Deliver

Published October 22, 2025

By Erika Lennon , Senior Attorney for the Climate and Energy Program at the Center for International Environmental Law.

This piece was originally published by Infobae in Spanish. It has been translated into English by CIEL.

This is also a six-part CIEL blog series unpacking the law, politics, and power shaping COP30 — and what it will take to deliver climate justice.

At this year’s global climate talks in Belem, Brazil, politics should take a backseat to the law. Known as “COPs” for conferences of the Parties, these annual talks bring countries together for negotiations centered on the climate treaties—UNFCCC, Kyoto Protocol, and the Paris Agreement. For the past 30 years, they’ve been mired in political gridlock, repeatedly failing to deliver the climate ambition and justice the world needs. This year, however, after two international courts confirmed that climate action and accountability are not political aspirations but legal obligations, the world has a critical opportunity to reset the climate negotiations. The message for COP30 is clear: Out with politics, in with the law.

For years, the United States and other big climate polluters have slowed progress to the pace of their political will, reducing climate policy to voluntary pledges and deflecting any focus on the root causes of the crisis. They often claim that well-established legal requirements to prevent environmental degradation and respect human rights don’t apply and all climate action is up to the discretion of States. Like obstinate children on the proverbial global playground, these States have essentially told the rest of the world, including those on the frontlines working to meaningfully address the climate crisis: “You’re not the boss of me.”

But in a historic moment for climate justice, the Inter-American Court of Human Rights (IACtHR) and the International Court of Justice (ICJ) have roundly rejected big polluters’ attempts to deny their responsibility for the climate crisis and downplay their legal duties to prevent and remedy its destructive consequences. In two separate rulings this July, they have sided with youth, climate-vulnerable nations, and frontline communities and given countries a boost to push back. 

In their landmark Advisory Opinions on climate change, these Courts have definitively ruled that ambitious climate action is not a political option. It is settled law, rooted not only in the climate treaties, but also in other multilateral environmental agreements, human rights law, and customary international law.  If States don’t act to  prevent harm and ensure the enjoyment of the right to a clean, healthy, and sustainable environment, they may face legal consequences. Not being a party to one of the climate agreements is no excuse and does not absolve a country of its legal obligations in the face of the climate emergency. Climate harm is not caused only by the direct emissions of greenhouse gases, principally from fossil fuels. It’s also driven by the actions that enable the fossil economy – including subsidies, lax regulations, and unchecked disinformation.  Therefore, climate action is not merely about replacing a coal plant with a wind farm, it encompasses how States legislate, regulate, enable participation, and address private sector behavior. 

Moreover, these landmark rulings have redefined the starting point for international climate negotiations and the ticket to entry for this year’s COP. If countries are to meet their obligations under international law, they cannot continue to put forward national climate plans (NDCs) that do the bare minimum. The ICJ has made clear that unless an NDC is more demanding than its previous one, reflective of the country’s highest possible ambition, and capable of keeping warming to 1.5°C, it runs afoul of the law. 

Nor can countries continue to adopt COP decisions that represent the lowest common denominator. This means no more vague declarations, disingenuous arguments, and delay tactics by polluters. These are our legal baselines and our new non-negotiables. The era of anything goes, with too little ambition and too many broken promises by big polluters, is over. The starting point for COP30 is not where last year’s talks landed, but where the law requires countries to be. And success at this year’s COP will not be measured by whether its outcomes on mitigation, adaptation, finance and just transition are in line with the previous one’s, but by whether they are  in line with science and the law. The urgency is palpable, as climate chaos unleashes ever more deadly floods, dangerous wildfires, and destructive hurricanes. Halting the climate crisis means stopping what is causing it — that’s what mitigation is. And that means a full, fair, fast, and funded fossil fuel phaseout. Action that is not sufficiently ambitious to meet the 1.5°C goal is not in line with the law.  And continuing to produce, use, and subsidize fossil fuels may violate international law – just ask the ICJ.  

Meeting real mitigation and adaptation goals requires real finance at a scale, not vague promises to mobilize it. Both courts have made clear: developed countries have a legal duty to provide this finance. Combatting the climate crisis will take the whole world. But this collective action must be based on equity and capacity,  recognizing the historic responsibility of the largest cumulative emitters and the rights of those who have contributed the least to the crisis but are suffering the most.

Rich polluting countries also have a legal duty to provide remedy and reparations for the harm they have caused and are continuing to inflict. One way is to pay up. Money isn’t the only form that remedy should take, but it’s a necessary part of righting historic wrongs and repairing present damage. And filling the Fund for Responding to Loss and Damage, launched at COP28, is a good place to start. Developed nations must come to COP30 ready to commit climate finance — for mitigation, adaptation, and loss & damage —  not out of charity, but as a legal duty.  

For years at COPs, corporate influence and lies have sapped ambition and sidelined the voices of those most vulnerable. But the IACtHR ruling acknowledged that States have legal obligations to stop the spread of disinformation and protect environmental human rights defenders. COP30 must therefore be a space where environment and human rights defenders are heard — not silenced or punished — and where science and facts guide decisions.

The IACtHR and ICJ rulings have ushered in a new era of accountability and opened a new path for climate justice. One of the first steps down that path is COP30. When government representatives gather in Belem, they must ensure every decision aligns with international law and the best available science. 

Youth, Indigenous Peoples, frontline communities, and advocates around the world have been demanding this for years — in capitals, in negotiation halls, and in the streets. Now, two of the world’s highest courts have made it clear: the law is on our side.

Read this piece and other blogs in the series on CIEL's website.