In a historic step, the International Court of Justice (ICJ) has ruled that countries have clear legal duties to fight climate change. This opinion, delivered in the case Obligations of States in respect of Climate Change, confirms that governments must take real action to protect people and the planet from the harmful effects of global warming. The ruling also says that failure to act could make countries legally responsible for climate-related damage, especially to small island nations and vulnerable communities.
The decision is based on a request made by the United Nations General Assembly through Resolution 77/276, adopted on March 23. It is the first time a court has spoken so clearly about climate change and its legal consequences. This opinion is important, as it provides a clear connection between climate change, states responsibility, and human rights under international law.
The International Court was asked two main questions:
- What are countries obligations under international law to protect the climate and environment from harmful greenhouse gas emissions?
- What legal consequences do countries face if they fail to do so, especially when it harms vulnerable countries and future generations?
These questions came from rising concerns by small island nations like Vanuatu and others who are already suffering from sea level rise, droughts, and extreme weather. Although countries like Vanuatu do not significantly contribute to climate change, they experience severe impacts as frontline nations.
The Court also confirmed that climate change treaties like the UNFCCC, the Paris Agreement, and the Kyoto Protocol contain binding legal duties for all participating countries. All parties have an obligation to adopt measures to mitigate greenhouse gas emissions. They also stated all countries have a duty to cooperate with each other to achieve the underlying objective of the framework.
Small and poor countries lack the infrastructure and resources to fight the immediate impact of climate change, like sea level rise and extreme heat waves. The court also states that parties must share their support with such countries through technology transfer and climate finance.
“States have a duty to prevent significant harm to the environment by acting with due diligence... from causing significant harm to the climate system... in accordance with their common but differentiated responsibilities and respective capabilities.”
Human Rights and Climate
The ICJ also confirmed that human rights law is part of international climate law. Countries must take steps to protect people from the negative effects of climate change because it can impact:
- The right to life
- The right to health
- The right to food and housing
This makes climate protection a legal human rights duty, not just an environmental issue.
Who Is Responsible When Harm Is Caused?
The ICJ said that any country that fails to act, or supports harmful actions like fossil fuel use, can be held legally responsible. This includes:
- Giving subsidies to fossil fuel companies
- Allowing harmful industrial practices
- Not regulating private companies that pollute
“Failure of a State to take appropriate action to protect the climate system... may constitute an internationally wrongful act.”
The Court explained that each country can be held responsible individually, even if many countries are involved in causing the harm.
Proving Responsibility: The Question of Causation
Some governments argued it’s hard to prove which country caused specific climate harm. But the Court disagreed. It said scientific methods can measure how much each country has contributed to global emissions, based on both current and historical data.
The Court ruled that: “A sufficiently direct and certain causal nexus” can exist between a country’s wrongful action and climate harm.
So, the idea that climate damage is too complex to assign blame is no longer accepted under international law.
What Happens When a Country Is Found Guilty?
The Court said that when a country breaches its obligations, it must:
- Stop the harmful action (cessation)
- Promise not to do it again (non-repetition)
- Make reparations to injured states, including restoring what was lost, Provide compensation for damages and public apologies or acknowledgements.
These responsibilities come under the law of state responsibility and apply even if multiple countries are involved.
Shared Responsibility, Global Consequences
The Court emphasized that climate protection is a duty owed to all countries. These are called obligations erga omnes — obligations every state owes to the global community. “All States parties have a legal interest in the protection of the main mitigation obligations set forth in the climate change treaties.” This means any country that signs climate agreements like the Paris Agreement can hold others accountable for failing to meet their duties.
The ICJ ended its opinion by saying it hoped the law would guide political and social action. The Court said it was supporting the work of the UN and the global community:
“Its conclusions will allow the law to inform and guide social and political action to address the ongoing climate crisis.”