Research & Developments is a blog for brief updates that provide context for the flurry of news regarding law and policy changes that impact science and scientists today.

The International Court of Justice (ICJ), the highest court of the United Nations, has ruled that all humans have “the right to a clean, healthy and sustainable environment.”

“The Court is of the view that a clean, healthy and sustainable environment is a precondition for the enjoyment of many human rights, such as the right to life, the right to health and the right to an adequate standard of living, including access to water, food and housing,” reads a line in the opinion, issued 23 July.

In a 2023 resolution, the United Nations requested that the ICJ provide an advisory opinion on the issue of states’ obligations with regard to climate change. The move was in response to advocacy by groups such as Pacific Islands Students Fighting Climate Change (PISFCC) and other members of vulnerable island nations. At the meeting where nations voted on the resolution, António Guterres, secretary-general of the United Nations, noted that advisory opinions, though not legally binding, “have tremendous importance” because they summarize and provide clarification on existing law.

In its nearly 80-year history, the Court has issued 29 advisory opinions. The latest opinion is one of just five to be reached unanimously by the court’s 15 judges.

The ruling could allow climate activists or other entities to issue lawsuits against countries that fail to comply with the decisions.

“States must take this ICJ ruling and use it to advance ambitious outcomes at COP30 and beyond. People and the planet deserve it,” Erika Lennon, senior attorney at the Center for International Environmental Law, told AP News.

Earlier in July, the Inter-American Court of Human Rights (IAHCR) similarly ruled that countries have a legal duty to avoid environmental harm and protect ecosystems. The first time an international court ruled on climate change was just last year, when the European Court of Human Rights ruled that countries have an obligation to protect people from the effects of climate change. As reported in The Guardian, the African Court on Human and Peoples’ Rights has recently begun a similar process.

The advisory opinion noted that the questions the justices set out to answer in the ruling—namely, what countries are obliged to do to protect the environment from climate change and what the consequences should be if they fail to do so—“represent more than a legal problem: they concern an existential problem of planetary proportions that imperils all forms of life and the very health of our planet.”

The timing is eerily coincident with the U.S. EPA’s plan to reconsider the “endangerment finding.” In the 2007 case Massachusetts v. EPA, the U.S. Supreme Court ruled that greenhouse gases are considered air pollutants, and that the EPA must determine whether they pose a danger to public health or welfare. In 2009, the EPA administrator signed the endangerment finding, declaring that greenhouse gases do endanger human health. On 22 July 2025, the New York Times and other outlets reported that the Trump administration had drafted a plan to repeal the finding.

—Emily Dieckman (@emfurd.bsky.social), Associate Editor

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