Climate Ruling by European Court Sharpens Paris Agreement’s Teeth

A group of Swiss women claimed in 2020 that Switzerland violated their rights by contributing to climate change-induced heat waves that threatened their health and well-being. On April 9, the European Court of Human Rights agreed with them, vindicating their complaint in Klimaseniorinnen v. Switzerland (although it simultaneously dismissed two other climate cases for procedural reasons, one brought by the former mayor of a French city and another brought by 6 Portuguese youth).

The Klimaseniorinnen ruling more broadly clarified human rights-based obligations for climate action. Yet, it didn’t articulate a new standard for human rights compliance. Rather, the court doubled down on a target that Switzerland (along with over 190 countries) had already endorsed under the Paris Agreement: reducing their greenhouse gas emissions in line with a 1.5°C rise in average global surface temperatures.

So, what exactly did the Klimaseniorinnen decision contribute to international law that wasn’t already there?

The answer is two-part. First, the court’s decision provided enforceable heft to what was previously a merely aspirational target for climate action.

Under the 2015 Paris Agreement, almost every country in the world agreed to “pursue efforts” to cap global warming to 1.5°C above pre-industrial levels, but this commitment was non-binding. The Klimaseniorinnen decision added some teeth to this 1.5°C target, asserting that Switzerland’s efforts to achieve it haven’t been sufficient under European human rights law.

According to the court, Switzerland is legally bound to take immediate action and to set intermediate greenhouse gas reduction goals in line with its proportionate contribution to international efforts aimed at limiting global warming to 1.5°C. The Committee of Ministers of the Council of Europe is tasked with ensuring that Switzerland abides by the court’s rulings, throwing the weight of a human rights compliance mechanism behind the Paris Agreement temperature threshold for the first time.

Second, the Klimaseniorinnen ruling sent a signal to courts, countries, and citizens around the world regarding how to best understand the legal obligations of governments in addressing the climate crisis.

Three other international legal entities are currently deliberating this question: the International Court of Justice, the Inter-American Court of Human Rights, and the International Tribunal on the Law of the Sea. These judicial bodies will undoubtedly look to the European Court of Human Rights decision in Klimaseniorinnen to provide context and clarity for their own rulings. The resulting accumulation of international legal pronouncements on the topic of governmental legal obligations regarding climate change will resonate for countries around the world.

In addition, the narrative force of citizens suing their governments for failing to ensure a stable climate system necessary for their viability and survival extends far beyond international law. People of all ages have already initiated a growing wave of climate rights litigation in domestic courts around the world, seeing courtroom success in countries ranging from Colombia to Germany to Pakistan.

In the US case, Held v. Montana, 16 Montanans successfully sued their state government for failing to protect their right to a clean and healthful environment as guaranteed under the Montana Constitution. Although the case is currently on appeal to the Montana Supreme Court, the plaintiffs have already seen a massive outpouring of support and media attention from around the country and the world.

Interest in the Klimaseniorinnen case has been similarly widespread. In addition to setting legal precedent, it and other rights-based climate cases are inspiring and informing both new and ongoing judicial advocacy approaches in domestic and international courts.

Even further, there is a great deal of fluidity between these cases and advocacy outside the courtroom. Many climate activists, including Greta Thunberg, have gotten involved in both court cases and political efforts to elicit a strong response to climate change. Courtroom hearings and developments in climate cases have frequently provided a platform for activism, protest, and other forms of political engagement.

Of course, any individual rights-based climate case is restricted to the narrow controversy presented in court and typically only goes so far in clarifying legal requirements. The Klimaseniorinnen case, for example, didn’t provide any specific protocols or prescriptions for how Switzerland can or should comply with the 1.5°C temperature target.

Yet, the decision provides a firm basis for governments to make their own determinations about how to comply with the specified requirements. The ruling will also likely provide legal support for further climate litigation either in Switzerland or other European countries.

The Klimaseniorinnen decision represents a monumental shift in climate change law. In addition to helping flesh out our growing global understanding of legal obligations in the context of climate change, the case will encourage other courts and citizens to provide contributions to that collective understanding through court cases, legislative or executive determinations, and other forms of legal action.

In the end, this momentum may very well be the case’s less direct but more impactful contribution to climate change response.

The case is Klimaseniorinnen v. Switzerland, Eur. Ct. H.R., No. 53600/20, judgment 4/9/24.

This article does not necessarily reflect the opinion of Bloomberg Industry Group, Inc., the publisher of Bloomberg Law and Bloomberg Tax, or its owners.

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Paul Rink is a visiting assistant professor of environmental law at the Elisabeth Haub School of Law at Pace University.

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