Climate protection by court decision

ICJ report sees states as having a duty to show more commitment in the climate crisis. Which climate lawsuits have been successful so far - and which have not

For the International Court of Justice (ICJ), a clean, healthy and sustainable environment is a human right. As it made clear in its opinion, states must show more commitment in the climate crisis. More and more courts are setting the framework for action against climate change: this overview shows which climate lawsuits have been successful - and which have not.

Author: Nina Schick

The legal opinion delivered by the International Court of Justice (ICJ) in The Hague on July 23, 2025 is 140 pages long. For more than an hour and a half, the presiding judge read out the key arguments on the commitment that states must show in dealing with the climate crisis. For the court, climate change poses a “universal and serious threat” to the global community, and the court believes that states have a duty to take measures to help reduce greenhouse gas emissions and adapt to climate change. A clean, healthy and sustainable environment is a human right.

The expert opinion was initiated by a student group from the island state of Vanuatu, whose territory of more than 70 islands is at risk of sinking as global warming progresses and sea levels rise. The proceedings before the ICJ are among the largest in its history. During the preceding two-week hearing in mid-December 2024, 96 states and 11 international organizations were able to present their arguments for and against states' climate protection obligations. The precise evaluation of the clearly structured report will keep legal experts busy for some time. The arguments will shape ongoing proceedings worldwide, which have been referred to internationally as “climate change litigation” for several years.

Climate change litigation around the world

“Climate change litigation” or simply “climate litigation” for short refers to legal proceedings related to climate protection. In German, the term “Klimaklagen” has become established. “Climate litigation” sounds catchy, but the term conceals very different procedures with different objectives, legal bases and constellations.

Every judgement, every decision and every advisory opinion reveals arguments that are important for communities of states, countries, companies, and populations in the face of increasing extreme weather events – even if the judges dismiss the case, as happened recently in the proceedings brought by a Peruvian farmer against the energy company RWE. Climate lawyers find and collect this information like mosaic tiles, piecing together climate change-related responsibilities to form a larger picture. Jannika Jahn, a senior research fellow at the Max Planck Institute for Comparative Public Law and International Law in Heidelberg, knows that there is no one-size-fits-all “standard procedure” in climate litigation proceedings. The regulations are too diverse, as are the ideas on how to use legal means to fight global warming.

Courts as climate protectors

 “Climate lawsuits can be of a civil nature if they are directed against companies, for example. They are grounded in public law when individuals or organizations seek to hold the state accountable,” explains Jahn. She has been observing international climate jurisdiction in her research work for several years. Lawsuits also differ in terms of the parties involved. Legal actions can be categorized as “horizontal litigation” when the parties meet at the same level. This is the case in civil litigation, but also in international law when states initiate proceedings before the International Court of Justice (ICJ). On the other hand, “vertical litigation” applies to cases in which individuals or initiatives want to oblige the state or countries to do more to protect the climate.

This overview shows which decisions provide useful clarity:

Decision of the Federal Constitutional Court on climate change 2021 – responsibility for the future

One of the most important decisions is the ruling made by Germany’s Federal Constitutional Court in 2021 concerning climate change. On 24 March 2021, the Federal Constitutional Court recognized that climate protection has constitutional status. The court declared parts of the German Climate Protection Act of 2019 to be unconstitutional. The law lacked concrete CO₂ reduction targets for the period from 2030 to 2050, which would compromise the civil liberties of young people and future generations. The court used the term “intertemporal civil liberties” for this – it found there to be a violation of rights in the present because civil liberties will be affected in the future.

“The decision marks a milestone in constitutional law and has given the climate protection movement a boost,” says Jannika Jahn. With the “temporalization of the constitution” – the inclusion of the future in the consideration of civil liberties – the court has made a far-reaching decision. However, the limits of the new legal concept quickly became apparent: a subsequent constitutional complaint calling for the introduction of a general speed limit was not even accepted for decision.

Urgenda Netherlands 2019 – the blueprint

The model for many climate litigation efforts is the decision by the highest court in the Netherlands in 2019 on a lawsuit filed by the NGO Urgenda against the Dutch government. The name is made up of the Dutch word for urgent (“urgente”) and agenda. With the lawsuit filed back in 2013, the foundation demanded that the Dutch government reduce emissions to a greater extent in order to protect the climate more effectively and won in all instances. The court obliged the government to decrease greenhouse gas emissions. The government’s measures included a stricter speed limit of 100 instead of 130 kilometres per hour on motorways during the day.

“The ‘Urgenda’ case is an example of successful climate litigation that has led to political changes and concrete measures,” explains Jahn. However, the Urgenda decision stands alone among climate litigation. “Climate litigation is not the appropriate instrument for shaping policy; the judiciary’s role is to define the legal framework.”

People’s Climate Case 2021 – poor prospects in European law

In 2018, a Swedish youth organization and ten families from five EU countries as well as Kenya and Fiji took the European Parliament and the EU Council of Ministers to court for a more efficient climate protection policy. The aim was to have the EU climate protection rules declared null and void (action for annulment). The General Court of the European Union (General Court) dismissed the action as inadmissible in 2019, as did the European Court of Justice (ECJ) at second instance in 2021, stating that the plaintiffs lacked the standing to bring an action and were no more affected than others – a difference in European law to the German constitutional complaint, which does not require a special, increased level of concern compared to others. According to the ECJ, climate change does not justify interpreting the criterion of individual concern more broadly than before.

The case made it clear: climate litigation has a difficult standing in European law. There is no equivalent to the German constitutional complaint in EU law. Very high admissibility requirements apply to the action for annulment, as in the People’s Climate Case. “This means that European law offers fewer opportunities for strategic lawsuits on climate protection,” says Jahn. Yet it would be a powerful instrument: European law would have a direct impact on national law – unlike the European Court of Human Rights (ECtHR), whose rulings are based on international law.

Swiss Climate Seniors 2024 – lack of climate protection violates human rights

On 9 April 2024, the European Court of Human Rights (ECtHR) in Strasbourg ruled in favour of the Swiss association Klimaseniorinnen (Climate Seniors). The ECtHR found that Switzerland’s climate policy did not adequately protect older women, who were particularly vulnerable to climate change, and thus violated their right to respect for their private life which is protected under Article 8 of the European Convention on Human Rights. The decisive trick of the case: the Climate Seniors had organized themselves as an association. The ECtHR would only thus recognize “victim status”. In view of the special nature of climate change, the Court emphasized the need for a right of an association to bring legal action and tightened up the criteria for this: this includes the association’s purpose of defending the human rights of its members and proof that the association could be considered qualified and representative of its members in order to advocate for their interests. The ECtHR expressly stated that it was not necessary to prove that the persons represented by the association fulfil the requirement of victim status themselves. However, the Court dismissed the complaints of four individual plaintiffs – they would have had to prove that they were specifically affected.

Climate law expert Jahn sees nothing unusual in this: “Actions brought by an association have always been very important in environmental law. This is demonstrated by the many lawsuits that have been filed in Germany by Greenpeace and Deutsche Umwelthilfe, for example.” Both associations continue to pursue climate litigation. In Switzerland, too, there are many indications of further legal disputes. Switzerland has not yet fulfilled the requirements for implementing the judgement.

Duarte Agostinho and Portuguese youths 2024 – prioritized in the national legal process

Also on 9 April 2024, the ECtHR handed down another high-profile decision in a climate protection case. It rejected the complaint lodged by six Portuguese young people against their country and 32 other states as inadmissible: the Court maintained that they should have first exhausted the legal process in their home country. Following the devastating forest fires in their home country in 2017, the young people had called for more effective climate protection measures from Portugal and other countries.

Jannika Jahn: “This was a case with a high chance of success against the complainants’ country of origin.” Unfortunately, the plaintiffs made an error of judgement. “I don’t understand why the complainants assumed that they could bypass the national legal process.” The case clearly shows that the rules of the game are strict: exhaustion of legal remedies, certain avenues of action, admissibility requirements, as well as limited opportunities for political organization. “Climate litigation is facing institutionale constraints,” says Jahn.

Saúl Luciano Lliuya v. RWE 2025 – companies bear responsibility for climate change

The case brought by Peruvian farmer Saúl Luciano Lliuya against the German energy giant RWE lasted more than ten years. On 28 May 2025, the Hamm Higher Regional Court dismissed Lliuya’s claim for a pro rata payment from RWE for protective measures against a flood wave from the glacial lake located above his town. The threat was not concrete enough. The NGOs that had supported the lawsuit nevertheless celebrated: the court recognized the fundamental responsibility of companies for damage to the climate.

The case of the Peruvian farmer is an example of horizontal litigation. Lliuya took civil action against RWE. “The RWE case will certainly lead to further lawsuits of this kind – though these may take years to resolve,” Jahn surmises. Providing evidence in these cases is particularly time-consuming. Several cases against major emissions creators are currently pending, including a sensational one in the Netherlands.

Milieudefensie v. Shell 2024 – NGO against oil giant

The Dutch environmental organization Milieudefensie has been suing the oil giant Shell since 2019 to reduce its CO₂ emissions. In 2021, Milieudefensie won the case at first instance – Shell had to reduce its emissions by 45 per cent by 2030 compared to 2019. However, the Court of Appeal ruled differently at the end of 2024: it overturned the decision in favour of Shell.

At the beginning of 2025, Milieudefensie appealed to the highest court. The decision is still pending.

“Rights of Nature” decisions – nature as a legal entity

“Rights of Nature” is a legal concept and an associated movement, not a single decision. The legal theory originated in the Global South and is now also being discussed in the Global North – the opposite of the usual course of events. The basic idea is that nature has its own rights that can be asserted in the legal system. Ecuador caused a worldwide sensation when it enshrined the protection of nature in its new constitution in 2008. In 2010, Bolivia passed its “Law on the Rights of Mother Earth”, which recognized nature in the form of “Mother Earth” as an entity with rights.

In Colombia, the Constitutional Court declared the Atrato River a legal entity in 2016. A separate organization, in which members of the riparian communities are also represented, forms the legal representation of the river together with the Colombian Ministry of the Environment. Other bodies of water and landscapes, as well as animals, have since been granted their own rights in Colombia.

The idea of “rights of nature” is spreading: in New Zealand, the River Whanganui became a legal entity in 2017, and in India the rivers Ganges and Yamuna followed in the same year. Uganda passed a law on the rights of nature in 2019. In 2022, the Mar Menor lagoon in Spain became a legal entity for the first time in Europe.

The “Rights of Nature” movement has arrived in Europe and is challenging the usual human-centred understanding of the law.

International Tribunal for the Law of the Sea 2024 – states must protect the oceans

Greenhouse gases not only end up in the atmosphere, but are also absorbed by the oceans. The result is known as “ocean acidification”: the pH value drops, coral reefs and other organisms are damaged. This is destroying people’s livelihoods, especially in small island states. Rising sea levels due to global warming are also putting entire countries at risk of disappearing. The climate crisis poses a particular threat to small island states. Nine of them from the Caribbean and the Pacific, including Tuvalu, Vanuatu, and the Bahamas, have therefore joined forces to form an interest group and are calling for better climate protection from the major countries.

In an advisory opinion on 21 May 2024, the International Tribunal for the Law of the Sea in Hamburg found that greenhouse gas emissions contribute to global warming and therefore constitute pollution of the oceans within the meaning of the UN Convention on the Law of the Sea. The 170 signatory states to the advisory opinion include Germany but not the United States. The countries are therefore obliged to reduce greenhouse gas emissions. The advisory opinion is not binding on the signatory states. However, it is helping to shape international climate protection law.

Inter-American Court of Human Rights 2025 – climate protection is a mandatory right

On 3 July, the Inter-American Court of Human Rights (I/A Court H.R.), which is based in Costa Rica, published an advisory opinion on climate law obligations. This was preceded by three hearings in Barbados, Manaus (Brazil) and Brasilia (Brazil); more than 260 written contributions were submitted and the final opinion, at 234 pages, is the longest in the history of the I/A Court H.R. The effort was great – as was the enthusiasm for the result among human rights activists and climate protectionists. The advisory opinion is celebrated as groundbreaking. There are several reasons for this. First, the I/A Court H.R, like the ECtHR in the case of the climate seniors, considers climate protection issues to be human rights issues. It even goes one step further and states that the human right to a healthy climate is a mandatory right (under international law: “ius cogens”), from which no exceptions can be made. In particular, the I/A Court H.R. declares all states of the Organization of American States (OAS) to be bound and thus also the USA and Canada, which are members of the OAS, but have not submitted to the I/A Court H.R.

The I/A Court H.R. also recognizes separate rights of nature in the sense of the “Rights of Nature” movement. It also calls on states to protect particularly vulnerable groups such as children, indigenous peoples and people in poor regions, and recognizes an intergenerational responsibility. The court also sees a duty on the part of states to act for the purpose of climate protection, in particular to expressly regulate companies. Democracy and the rule of law have a special role to play in the climate crisis: the advisory opinion emphasizes the need for access to information, participation and the openness of legal channels for all. The I/A Court H.R. also takes a detailed look at migration triggered by the climate crisis and calls on states, for example, to develop procedures for displaced persons.

As ground-breaking and progressive as it is, the advisory opinion has no legal force. The judiciary can only provide the impetus by defining the legal framework and obligations; it is the responsibility of politics to develop the means and instruments to implement them

Ongoing proceedings across the globe

Numerous climate ligation efforts are still pending around the world. Columbia Law School in New York maintains a database on global climate change litigation. In June 2025, it contained more than 3,000 cases, both those already decided and those still ongoing. Like the RWE case, the Shell case is directed against a company. “In Germany, all corporate lawsuits have failed so far. In general, lawsuits against states have a higher probability of success than those against companies,” says Jahn. However, she also notes: “At the moment, the euphoria that prevailed immediately after the German climate decision by the German Federal Constitutional Court has somewhat ebbed away.” The failure of the speed limit complaint showed that climate litigation is not suitable for enforcing concrete political measures.

Meanwhile, climate change continues. Damage and risks are becoming more concrete, and the scope for achieving the climate targets that have been set is becoming smaller. “Courts play an important role,” says Jahn. “Even though they hold no political power, they serve a crucial oversight function in a democratic constitutional state. If they fail to intervene at all, compliance with binding emission reduction targets remains unchecked – and therefore unverifiable by citizens. Precisely because the German Federal Constitutional Court has acknowledged that human rights violations are possible in this context, it is essential that political decision-makers are held accountable for their actions on climate protection..”