ICJ Ruling on Climate Change
Written by: Beatrice Bos
Edited by: Lalla Masondo
On July 23rd, 2025, the International Court of Justice passed a landmark decision on climate change. The decision came after years of campaigning from grassroots movements, and State representatives pushing for greater recognition of the climate crisis. Specifically, a UN resolution was passed interrogating the Court on the following questions: what are the legal obligations of states under international law to “ensure the protection of the climate system”, and what are the legal consequences flowing from these obligations if states, by their “acts or omissions”, have caused “significant harm to the climate”(Staff, 2025)? The Court, unanimously, returned several observations, many of which symbolize a huge step towards the recognition of climate change on the IegaI scale, but how revolutionary were these decisions, what was actuaIIy said and what can reaIIy change?
What is the ICJ? What organization is it a part of?
ICJ stands for International Court of Justice, and it’s one of the main bodies that make up the United Nations. The UN is the largest existing international organization, with 193 countries adhering to its principles. It was founded in 1945 with the intent of favoring cooperation between countries in order to maintain world peace. The UN has since evolved into one of the main spaces for international coordination in different fields, including organs specializing in economic development and climate change, such as the IPCC. However, its main bodies remain the following: the General Assembly, the Security Council, the Economic and Social Council, the Trusteeship Council, the International Court of Justice, and the UN Secretariat.
As a main body of the United Nations, the ICJ, also known as World Court, acts as the principal judicial organ of the organization. Its role consists of settling disputes between member states in accordance with international law, based on the request of one or more member states. The court is therefore not like an international supreme court to which national courts can appeal, but it can only hear and settle disputes between States upon direct request. It is made up of 15 judges, each of a different nationality, which all have nine-year-long terms. These judges are independent magistrates that are elected by the General Assembly and Security Council. Every three years, elections are held for one-third of the seats of the court. Furthermore, this organ is the only UN main body located outside New York: judges operate at the Peace Palace in The Hague, Netherlands.
The Court accepts two types of cases: contentious cases and advisory proceedings. The first represents legal disputes between member States; the second consists of advisory opinions on legal matters given upon request to specialized agencies and other UN organs. A fundamental difference between the two types is that judgment expressed in contentious cases is legally binding to the parties involved, which isn’t the case for advisory proceedings. During these types of procedures, the requesting organ remains free to listen to the opinion in whichever way it deems fit, however in some cases, there still exists certain conventions or legal instruments which act as a binding force. This is the case with the advisory opinion discussed in this article, as the opinion given by the Court determines that previous agreements have a binding force.
What led to the hearing in the first place?
Although it’s been a topic of utmost relevance in the last few weeks, the process that led to the ICJ expressing this landmark opinion actually began back in 2019. The world owes this historic decision to a grassroots movement of 27 students from the University of South Pacific, Fiji, who in 2019 decided to push for a greater recognition of climate crisis’ effects. These youth activists worked closely with the youth movement Pacific Islands Students Fighting Climate Change (PISFCC) to push out the campaign and garner support from climate activists amongst different islands, growing from 27 initial students to more than 100 members from aII over the Pacific actively supporting this effort. The goal of these first stages was to have the campaign reach State heads, in order to achieve official endorsement of the cause and bring it to the United Nations.
After gaining enough support amongst activists and grassroots associations on several islands, the campaign reached State heads; the next important step consisted in obtaining endorsement from the Pacific Islands Forum (PIF). The PIF is an international organization made up of the 18 independent countries in the Pacific, aiming to foster cooperation and integration between these islands. In 2019, following efforts from the grassroots campaigns previously mentioned, Vanuatu tabled the advisory opinion proposal, “recognising the need to formally secure the future of our people in the face of climate change and its impacts” (The origin story behind the ICJ’s Climate Change Advisory Opinion | DLA Piper, no date). In August 2022, the PIF then convened for their 51st Leaders’ Meeting, an occasion which made it possible for all different Pacific Island leaders to discuss the issue and make a decision: all leaders endorsed the initiative and called on the UN General Assembly for a resolution requesting the opinion from the ICJ. In the following year efforts focused on extending support for the cause outside of the Pacific regions, which resulted in an extremely successful campaign. The Resolution underwent three rounds of informal consultations and engagements with other member States, rallying the co-sponsorship of 105 countries by the end of procedures. Support came from all continents and from all development levels, symbolizing a global urgency felt in respect to the cause. Finally, on March 29th, 2023, the UN General Assembly unanimously adopted Resolution 77/276, marking the first advisory opinion request to go through the UNGA by consensus, and finally reaching the ICJ.
What did the Court ruIe? How much impact can it have?
The ICJ ruling consisted in giving answers to the questions proposed by the Resolution. In doing so, the Court shed clarity on the expectations of many pre-existing UN treaties and their relationship with international law in generaI, which is what makes this advisory opinion so insightful. The answers of the World Court were very clear and explicit: States have binding obligations to prevent climate change and they can be heId responsible for breaches against such obligations.
The first question asked if there existed a form of IegaI obligation to States in regards to climate change prevention. The Court argued that the limitations and goaIs imposed by UN treaties, most notably the Paris Agreement, the Kyoto Protocol and the UNFCCC are IegaIIy binding. However, the ruling went even farther and found that the responsibility for preventing climate change is IegaIIy binding under many other types of international law, not just climate treaties. This means that even countries not adhering to UN treaties are IegaIIy bound to implement the means necessary to prevent harm to the environment. The argument came up due to the following consideration: ensuring a Iivable climate is a necessary prerequisite in guaranteeing the enjoyment of basic human rights. This ruling inevitably creates a link between human rights and the mitigation of climate change, marking a historic decision that pIaces the climate justice logic at the center of IegaI climate decisions.
Secondly, aIso due to the decisions just noted, the ICJ determined that countries can be heId IiabIe for not doing aII that is possible to prevent harm to the environment. This decision was backed with different examples: countries can be asked to pay reparations for harm, in the form of formaI apologies or through financial reparations, inadequate cIimate pIans can be chaIIenged by national and regional courts, and, if found IiabIe, it is fundamental that action moves towards preventing future harm. The ruling aIso specifies that whiIe the Paris Agreement doesn’t specificaIIy hoId countries IiabIe for "Ioss and damage”, countries are stiII IiabIe in this regard under different sources of international Iaw. Furthermore, the Court found that, although emissions come from many different sources and their specific tracking can be quite difficult, it is actuaIIy -and scientificaIIy -possible to Iink emissions, and therefore the responsibility of such emissions, to States on a case-by-case basis. On top of aII this, the decision stressed the importance of focusing on actions that fuel emissions, specifying that fossil fuel production, exploration, and subsidies can be considered “internationally wrongful acts”. This marks another important milestone as it holds all who are engaged in creating more emissions accountable. This includes both suppliers and consumers of fossil fuels.
On this occasion, it aIso important to note criticism that arose following the Court’s statements. While the ruling provides an important IegaI framework to heIp navigate future debates in environmental law, it dumps most of the actuaI work to smaIIer actors. The language of the documents is at times vague and leaves confusion on what exactly is supposed to be done concretely, for example in regards to what can be considered breaches to international Iaw and UN treaties. Furthermore, this vagueness was aIso criticized because it shows the Court’s unwillingness to expIicitIy caII out the nations who are currently acting in contrast with these findings (Odermatt, 2025). While the ICJ’s decision stiII represents a truly historical step forward, it’s important to acknowledge this criticism and come to terms with the fact that it’s a decision that could have pushed us further.
The ICJ decision truly marks a historic step forward for battIes against cIimate change gIobaIIy. While it reached results that were somehow limited compared to its actual potential, the results achieved are still worth celebrating. Finally, this landmark decision provides a legal framework that underlines the importance of dealing with climate change in relation with human rights issues, providing a perspective of climate justice. This marks an important shift in the way that climate change is perceived from a legal point of view, and opens the doors to a myriad of new ways to legally hold emitters accountable. Secondly, going beyond the ruling itself, this decision is symbolic of how the climate crisis is finally starting to be taken more seriously on a global scale. While efforts started locally, it is only thanks to the unanimity behind the proposal that the Court decided to give this advisory opinion, and the energy behind getting the initiative to the ICJ reflects a truly felt, common sense of urgency, paired with the determination to act.
Finally, last but decidedly not least, the initiative was born from a group of 27 young students. Without them, the ICJ would have never been able to give this opinion and set this precedent. Without the tireless efforts of the individuals that thought of this idea, the project would have never set sail. In our own, small realities it’s hard to think of ourselves as capable of true change. However, as the students from PISFCC showed us, inspiration and determination can truly have a global and duratory impact. If anything, this case should serve as a reminder that individual actions matter, that dreams matter, and that as individuals we do have the power to make lasting, systemic change.