Research - 13.12.2024 - 16:30
Climate change in court: how the International Court of Justice (ICJ) reinterprets global obligations
From 2-13 December 2024, the ICJ held public hearings in The Hague on an advisory opinion that sheds light on the legal obligations of states in the fight against climate change. These proceedings, initiated by a resolution of the UN General Assembly, are not only a legal and historical event, but also offer a unique opportunity to observe the development of customary international law. The submissions of the countries include written statements from 91 states and organisations. Prof. Dr. Thomas Burri and his team have statistically analysed them. His analysis is like an X-ray looking into 10,000 pages of legal opinions.
Important results of the analysis
- The majority of states want to strengthen international law
– 67 % of the written submissions are in favour of a broad scope of international law on climate change, which goes beyond existing climate treaties and includes customary law, human rights and the law of the sea.
– 15 % favour a narrow focus, limited to existing climate treaties such as the Paris Agreement.
– 18 % of submissions do not take a clear position on this question.
- States should be held accountable
Three quarters (75 %) of the submissions emphasise the importance of the general law of state responsibility, including in the context of climate violations. This could amount to liability for violations of customary law or general obligations. Only 15 % believe that the Paris Agreement supersedes general international law. These states include Great Britain. The US, which already withdrew from the Paris Agreement during Donald Trump's first term in office, considers state responsibility to be relevant, but only in a narrow sense.
- Majority want cross-border damage from greenhouse gases to be outlawed
A clear majority of participants (76 %) would like to see the principle of “do no transboundary harm” applied to greenhouse gas emissions as well. This could lead to a global obligation to reduce emissions, independently of specific climate treaties such as the Paris Agreement. Only 14 % reject this applicability, with the United Kingdom and the United States in particular putting forward alternative arguments in the event that the ICJ were to declare the principle applicable.
- Application of human rights in climate change matters
38 % of submissions support extraterritorial application of human rights in the context of climate change, particularly in the case of transboundary impacts. This implies the responsibility or duty of each state to prevent human rights violations outside its territory as well. 19 % reject this and argue in favour of a restriction to territorial obligations. The remaining 43 % did not express a clear opinion on this question.
- Strengthening international law in the fight against climate change
Many submissions emphasise the need for a coherent interpretation that integrates environmental law, human rights and general international law in order to legally address the global nature of climate change.
Historical significance of the proceedings
The advisory opinion procedure at the International Court of Justice (ICJ) to clarify the obligations of states under international law in dealing with climate change has already acquired historical significance before the judgment is handed down. With written submissions from 91 states and organisations, it is the most extensive procedure in the history of the ICJ. Almost all UN member states are directly or indirectly involved, including many that are appearing before the court for the first time, such as small island states.
Further development of international customary law
A key aspect of the proceedings is the potential further development of international customary law. The large number of so-called “opinio iuris” statements – i.e. legal convictions of states – offers a unique opportunity to analyse the emergence and consolidation of customary international law. Particularly relevant is the question of whether and how the principle of avoiding transboundary harm can be applied to man-made greenhouse gas emissions. The majority of the comments submitted support this applicability, which indicates that a global obligation to reduce emissions could become established independently of specific climate treaties.
Human rights and climate change
Another focus is on human rights in the context of climate change. While the European Court of Human Rights (ECHR) has so far limited states' climate obligations to their territory, the ICJ's findings could strengthen extraterritorial jurisdiction. This would be particularly important for states whose significant emissions clearly have cross-border impacts, affecting small island states and particularly vulnerable populations.
Relationship with the Paris Agreement and other areas of law
The proceedings also shed light on the interconnection between different areas of law. The ICJ will clarify whether existing climate treaties such as the Paris Agreement are to be considered a lex specialis – i.e. a special law that supersedes general international law – or whether general international law and human rights are also applicable in parallel. This decision could have far-reaching consequences for international climate policy.
Finally, the advisory opinion could serve as a precedent for future proceedings. It not only provides orientation for dealing with climate issues in international law, but could also be used as a blueprint for other global challenges such as biodiversity loss or environmental pollution.
A summary of the analysis and the data used in the analysis are available for download.
Main image: Adobe Stock / Deemerwha studio