The circle is complete. Ten years after the Dutch court issued its famous ruling in the Urgenda case, the International Court of Justice has confirmed that all states are legally obliged to pursue effective climate policy.

On July 23, 2025, the International Court of Justice in The Hague (ICJ) issued its advisory opinion on the legal obligations of states in the field of climate change. This advisory opinion was issued by the ICJ at the request of the United Nations General Assembly, which adopted a resolution to that effect on March 29, 2023. Although the ICJ’s ruling is not binding, it nevertheless carries great legal and moral authority due to the ICJ’s status as the highest judicial body of the UN.

The ICJ underscores the correctness of the Dutch judges’ ruling in the Urgenda case. Ten years ago, that case established for the first time worldwide that a national state—the Dutch State—has an obligation to its citizens to pursue sound climate policy by significantly reducing greenhouse gas emissions from society and the economy. This groundbreaking ruling was made in 2015 on the basis of Dutch national law. Since then, similar court rulings have been made in other national jurisdictions, including in our neighboring countries Belgium and Germany.

In the past 18 months, the European Court of Human Rights and the Inter-American Court of Human Rights have also ruled that states have a climate obligation towards their citizens. According to these human rights courts, failure to comply with the necessary emission reduction obligations constitutes a violation of important human rights obligations, such as the right to life, health, and well-being. The Supreme Court had already ruled this in the Netherlands in 2019.

Now, the International Court of Justice has reached a similar conclusion based on international law, the law that governs relations between nation states. The ICJ has ruled that the Netherlands, Belgium, Germany, and all other nation states in the world have emission reduction obligations towards each other and must ensure good climate policy. They have a duty to cooperate to this end and can also demand this of each other.

The ICJ has confirmed that the obligations to pursue sound climate policy derive, among other things, from human rights treaties and—not surprisingly—from international climate treaties. There is now no doubt that human rights law plays a central role in tackling the climate problem. The ICJ also recognizes that the right to a clean, healthy, and sustainable environment is an essential condition for the protection of other human rights and that it is therefore difficult to imagine that states can fulfill their obligations under human rights treaties without also protecting the right to a clean and healthy environment. In doing so, the ICJ follows the earlier qualification by the UN Human Rights Council and the UN General Assembly that the right to a clean, healthy, and sustainable environment is a fundamental human right.

The ICJ also shows that the obligations to pursue good climate policy do not only follow from climate and human rights treaties, but also from other international environmental treaties and from international customary law. In particular, the Court points to the customary law obligation applicable to every country not to cause significant damage to the environment and to cooperate with other countries to protect the environment. According to the ICJ, this obligation also applies to the climate system as part of the environment.

According to the ICJ, all these important sources of international law point in the same direction and indicate a climate obligation for each country individually. States cannot therefore hide behind the lack of climate action in other states in order to avoid fulfilling their own climate obligations.

The climate obligation is a weighty duty of care, which, according to the Court, must be strictly enforced because of the enormous and partly irreversible damage that climate change is causing around the world. In this context, the ICJ refers to climate change as an existential problem of planetary proportions that threatens all life forms and even the health of our planet.

This raises the question of what this serious duty of care actually entails in practice. In short, the following can be said about the emission reduction obligation of states (other climate obligations, such as the adaptation obligation and the obligation to provide financial support to developing countries in their climate approach, are not considered here).

Firstly, the ICJ states that the central objective of the climate treaties agreed by states is to limit global warming to 1.5°C above pre-industrial levels. To achieve this, global CO2 emissions must be reduced to net zero by 2050. The significant effort obligation of countries must therefore be aimed at ensuring that each country makes its fair and equitable contribution to achieving that global 1.5°C target through rapid and far-reaching emission reductions.

This fair and equitable reduction contribution must be reflected in each country’s increasingly ambitious national contribution, which each country must submit regularly under the Paris Agreement. When determining and implementing these national reduction contributions, the principle of fairness (and its legal implications) dictates that developed countries must take the lead at the global level by reducing their emissions rapidly, significantly, permanently, and across the entire economy. Developing countries are given slightly more time to reduce their emissions.

This greater obligation on the part of developed countries such as the Netherlands, based on the principle of fairness, is founded on the fact that their economies have contributed significantly to the total amount of greenhouse gas emissions since the Industrial Revolution, the fact that their contribution to the climate problem is still very large (especially when calculated per capita), developed countries have a high degree of socioeconomic development and have the economic resources and technical, institutional, and administrative infrastructure to be the first to implement far-reaching national emission reductions, according to the Court.

Secondly, the ICJ points out – following the states’ own considerations in this regard in the Paris Agreement – that IPCC findings show that a change in consumption and production patterns and a change in lifestyle are necessary to mitigate the climate problem and its serious consequences. According to the ICJ, one consequence of the significant obligation to make efforts is therefore that states must take appropriate action with regard to the production and consumption of fossil fuels and that action must be taken against the subsidization of fossil fuels and the issuance of new exploration licenses for fossil fuels. This should be viewed against the background of the ICJ’s finding that the burning of fossil fuels is the main cause of climate change and that moving away from fossil fuels is an important measure for reducing greenhouse gas emissions.

Thirdly, under the duty of care to protect the climate, states have an obligation to regulate private actors (such as companies and financial institutions) within their jurisdiction in order to achieve the necessary rapid and far-reaching emissions reductions and to reduce the emissions of these private actors. The Court clarifies that the state does not thereby assume the responsibility of these private actors, but merely fulfills its own serious duty of care to reduce national greenhouse gas emissions (over which the state can exercise control) through regulation.

Those who fail to comply with these state obligations may be held accountable by other states for the adverse climate effects that result. Further emission reductions may be demanded, but also, for example, damages or other forms of compensation. If the Dutch state or the EU (which is an independent party to the climate treaties) fails to regulate private actors sufficiently, they may be held accountable under international law by other countries for the excess emissions of companies within their own jurisdiction.

The ruling thus effectively indicates that the EU and the EU member states were on the right track in adopting the CSDDD Directive as a regulatory framework for companies in relation to tackling the climate problem. It is also a clear indication that the scaling back and dismantling of this directive, a process that is now in full swing, may well be contrary to international law and its underlying sources, such as human rights law.

The above obligations naturally apply equally to other major emitting countries such as the US and China, to be determined for each country on the basis of, among other things, the principle of fairness. A country cannot evade this obligation under international law, not even by withdrawing from the Paris Agreement, as the US has done. After all, as mentioned above, customary law, which is binding on all states, stipulates that states have a duty not to cause significant damage to the climate system and a duty to cooperate with other countries to protect it. These duties are binding on every state under customary law, regardless of whether a state is still a party to a treaty such as the Paris Agreement.

In short, there can no longer be any misunderstanding about what the international legal order and human rights law require of states in relation to tackling climate change. How states will respond to this ruling by the International Court of Justice remains to be seen. Perhaps there will be more clarity in a few months’ time, at the UN climate conference to be held later this year in Brazil, where the international community of countries will once again sit down at the negotiating table. In any case, there will be an opportunity for countries that are willing to make a reasonable contribution to put more pressure on countries that are lagging behind. The larger the coalition of countries willing to increase the pressure, the greater the chance that the global climate approach can still gain momentum. That is a desirable outcome, because it is not yet possible for all countries to jointly implement policies that will keep the 1.5°C target within reach.

If too little progress is made in the coming period, the ICJ ruling will undoubtedly lead to an increase in national climate lawsuits and possibly also to a group of states daring to take up the gauntlet and increase pressure on other countries through international legal proceedings.

In any case, 10 years on, the ICJ ruling proves that the Dutch judges in the Urgenda case were right. Now that their insights have gained worldwide recognition, let’s hope that it will be easier to make progress in tackling what the International Court of Justice has rightly labeled an existential problem for humanity. Because that is what global warming really is, and hopefully this ruling will help to raise awareness of this fact in global society.

This message was written by Roger Cox. The climate team at Paulussen Advocaten represents Milieudefensie and other social (environmental) organizations in climate cases, including the cases against Shell and ING. In addition, Paulussen advises various (decentralized) governments on sustainability regulations and policy.

For more information, please contact us at +31 (0)43 321 6640 or info@paulussen.nl. Appointments can be made on location or at our offices in Maastricht and Heerlen.

Nieuws Overzicht