Legal reckoning: Courts redefine global climate accountability

Amid rising geopolitical tensions, pressure to meet climate obligations increasingly comes from courts. Earlier this year, both the International Court of Justice (ICJ) and the Inter-American Court of Human Rights (IACtHR) issued landmark advisory opinions affirming that countries must address climate change — and that failure to do so may carry serious legal consequences.

This renewed legal clarity comes at a critical moment. Last year was the hottest on record, with global temperatures surpassing 1.5° Celsius above pre-industrial levels. Yet the gulf between the urgency of the threat and the policy response continues to widen.

In the absence of political will, the legal system has become a key driver of climate progress. As the United Nations Climate Change Conference in Brazil (COP30) approaches, the groundwork has been laid for stronger, fairer, and more accountable climate action. Governments must now align their policies with both international law and environmental necessity.

The most immediate implication of the ICJ and IACtHR opinions is that national climate plans — known as Nationally Determined Contributions (NDCs) — must reflect the “highest possible ambition” and align with the Paris Agreement’s goal of limiting global warming to 1.5°C. Yet, as of 2024, global temperatures are on track to rise by as much as 3.1°C by the end of the century. Following the September deadline for new NDCs, only half of global greenhouse-gas (GHG) emissions are covered by updated pledges, most of which fall far short of science-based targets.

Still, the ICJ and IACtHR decisions offer cause for hope. At COP30, negotiators and civil-society representatives can push for more ambitious measures, knowing that noncompliance with the Paris goals can now be challenged not only in diplomatic forums but also in courts.

A rapid phaseout of coal, oil, and gas remains essential to effective climate action. But despite the “UAE consensus” to move away from fossil fuels, many countries continue to obstruct progress. Here, too, the ICJ provides negotiators with new tools, explicitly recognising that governments may be held liable for failing to reduce GHG emissions — including through fossil-fuel production, consumption, exploration, and subsidies.

The international climate regime must evolve to reflect these changing legal realities. That requires stronger compliance mechanisms to ensure that countries meet their targets and deliver on climate-finance commitments.

The legal shift is particularly striking in climate finance. For decades, developed countries have treated funding for adaptation and loss and damage as discretionary. Consequently, despite the establishment of the Fund for Responding to Loss and Damage at COP28, contributions remain far below what is needed.

The ICJ’s opinion makes clear that wealthy countries have a legally binding duty to support mitigation, adaptation, and loss-and-damage efforts across the developing world. Meeting these obligations will require mobilising at least $1.3 trillion annually by 2035, with dedicated provisions for loss and damage.

Crucially, the private sector is not being let off the hook. The ICJ, IACtHR, and the International Tribunal for the Law of the Sea have all affirmed that governments must regulate corporations to protect the environment, safeguard the climate system, and uphold human rights.

Corporate accountability is also taking shape in domestic courts. In a landmark decision, Germany’s Higher Regional Court of Hamm ruled that large emitters can, in principle, be held liable for climate-related impacts. The case, brought by Peruvian farmer Saúl Luciano Lliuya, shows that individuals on the front lines of the crisis can compel major polluters to pay their fair share.

But litigation alone cannot deliver justice at scale. Governments must establish clear legal frameworks to hold major emitters accountable before the damage becomes irreversible. Mechanisms such as mandatory reserves, disclosure rules, insurance schemes, and compensation funds can internalise liability risks and embed accountability into the system rather than leaving it to goodwill or the courts.

Momentum for such measures is building. In countries like the Philippines and Pakistan, and US states such as Vermont and New York, lawmakers are advancing “polluter pays” legislation. Around the world, plaintiffs — from Indigenous groups in Canada to farmers in Korea — are invoking the ICJ’s reasoning, and a Brazilian court has already cited it in ordering a fossil-fuel project to cease operations. Instead of waiting for more court rulings, governments should now act to uphold the rule of law and confront the climate crisis.

A decade after the Paris Agreement, the world can no longer afford half-measures. Vanuatu has already announced plans to pursue a new UN resolution aimed at translating the ICJ’s opinion into concrete political action. By supporting this initiative and acting decisively now, policymakers can help build a global climate regime capable of delivering real solutions at the speed and scale this crisis demands.

Project Syndicate