UN General Assembly Adopts Resolution Endorsing Advisory Opinion on Climate Change

On May 20, 2026, the United Nations (UN) General Assembly adopted a historic resolution on climate change by a large majority. Resolution A/80/L.65 itself is not technically legally binding upon States, but it is nonetheless noteworthy as an affirmation from States of what they believe international law requires of them.

The story behind this resolution began in 2019, with a group of young law students in a classroom on a small island in the Pacific. These students were concerned that the international community seemed more interested in continuing to enable lucrative activities that were propelling climate change, while remaining willfully blind to the existential crisis that those in the Pacific could see unfolding around them: sea level rise gnawing away at their territories, severe storms putting their homes and loved ones at risk, irregular weather patterns and droughts making it increasingly difficult for communities to grow their own food, and saltwater seeping into their sources of drinking water. In these students’ communities, climate change was not a distant or abstract issue that could continue to be postponed. Their people were suffering real harms, and so they began to dream of fighting for a legal solution where political will had fallen short.

The students advocated first before their own governments, and later beyond their region, for an initiative to be brought before the UN General Assembly, asking this body to request an advisory opinion from the International Court of Justice (ICJ), the international community’s highest court. A coalition of small island countries led by Vanuatu championed the idea before the rest of the UN General Assembly, resulting in a 2023 resolution, adopted by consensus and with no States objecting, asking the ICJ to weigh in on:

1. whether States are obligated, under international law, “to ensure the protection of the climate system and other parts of the environment from anthropogenic emissions of greenhouse gases for States and for present and future generations;” and
2. whether there are “legal consequences under these obligations for States where they, by their acts and omissions, have caused significant harm to the climate system and other parts of the environment,” which have in turn adversely affected other States, as well as Peoples and individuals of present and future generations.

During the process of collecting contributions to inform its advisory opinion, the ICJ collected an unprecedented number of written and oral statements and comments from both States and civil society organizations. The oral hearings on the matter lasted two weeks and included testimony from 96 States—about half of the membership of the UN—some States appearing before the ICJ for the very first time. Ultimately, in July 2025, the ICJ delivered a unanimous opinion—something that happens in less than 1 out of every 5 ICJ advisory opinions.

The advisory opinion first acknowledged “the significant and devastating consequences . . . of climate change . . . and the imminence of the threat it poses to . . . populations, territories, economies, [and] cultural traditions” as well as, “for some, the very existence of their State.” It also recognized that climate change, along with its causes and far-reaching effects, constituted a “scientifically established phenomenon.” It then identified as applicable sources of law not only existing climate change treaties, but also the UN Charter, other sources of environmental law, law of the sea, and even international human rights law. In response to the questions set before it, the ICJ determined that States’ obligation to prevent significant transboundary harm by acting with due diligence, long-established under international environmental law, also applied in the context of climate change. Rejecting arguments that climate change was too diffuse a phenomenon to establish risk and causation, the Court was of the opinion that “due diligence” in the climate change context could be measured by State compliance with actions required to accomplish the goals of the UNFCCC, the Kyoto Protocol and the Paris Agreement.

Tracking closely the language of the ICJ’s opinion, the resolution adopted in the UN General Assembly last month called upon States to comply with these obligations of prevention and due diligence, including “implement[ing] measures” and cooperating with each other “to achieve the collective temperature goal of holding the increase in the global average temperature to 1.5 degrees Celsius above pre-industrial levels.” The resolution further echoed the Court’s determination that legal consequences of a breach of climate change obligations include “cessation of the wrongful actions or omissions,” as well as providing guarantees of non-repetition and reparation of harms caused. The General Assembly also endorsed the ICJ’s assessment that loss of territory due to climate change does “not necessarily entail the loss” of a State’s legal identity as a sovereign State, and reaffirmed States’ obligations to avoid returning refugees who face a risk of irreparable harm to their lives. In addition to reaffirming the advisory opinion, the General Assembly’s resolution lays out two future follow-up actions: a 2027 report by the UN Secretary General outlining “ways to advance compliance . . . in relation to the Court’s findings,” and the inclusion of the matter in the agenda for the General Assembly’s 2028 session.

International law is built on consent: States are bound only by legal obligations they have agreed to, either by becoming party to a treaty or by joining other States in adopting specific practices or behaviors out of a sense of legal obligation. When States bring a dispute before the ICJ, they similarly consent to be bound by the Court’s decision. Advisory opinions work differently — without that specific consent, they are not legally binding in the same way. The ICJ, as the UN’s principal judicial organ, has the authority to identify, interpret, and clarify what the law is, but because international law depends on State consent, States could in principle reject that interpretation. When States instead affirm an advisory opinion as they did in passing Resolution A/80/L.65, that choice matters: it signals that States accept the Court’s conclusions as an accurate statement of the law. When presenting the resolution for a vote, the representative of Vanuatu framed the decision as a test of “whether the multilateral system [built at the end of World War II] can [still] do the most basic thing we ask of it: respond to legal clarity in good faith, rather than retreat from it; whether international law still holds in the face of what the Court called ‘an existential problem of planetary proportions that imperils all forms of life and the very health of our planet.’” With a vote of 141 States in favor of the resolution, 8 against, and 28 abstentions, a large majority of nations have shown their continued commitment to answering in the affirmative.