7 Key Things to Know About the ICJ Advisory Opinion Hearings on Climate Change

An advisory opinion from the ICJ is a legal interpretation provided in response to a question posed by authorised entities, such as the UN General Assembly. While not legally binding, these opinions are highly persuasive and often guide international law and policymaking.

In the current proceedings, the UN General Assembly has asked the ICJ to clarify the obligations of states to address climate change under existing international legal frameworks. Specifically, the court will examine the legal consequences of states' actions—or inaction—on climate change and their impact on vulnerable nations, communities, and future generations.

Advisory opinions are especially significant in cases like this, where the stakes involve global challenges requiring collective action. They can serve as a foundation for future legal claims or inspire new international treaties.

The ICJ is tasked with addressing a highly complex and multi-faceted question regarding the obligations of states under international law to address climate change and its consequences. The questions, as posed in the United Nations General Assembly (UNGA) Resolution A/RES/77/276, highlight key principles and treaties in international law.

a)        What are the obligations of states under international law to ensure the protection of the climate system and other parts of the environment from anthropogenic emissions of greenhouse gases for present and future generations?

This question requires the ICJ to examine the scope of state obligations under a variety of international legal instruments. It brings together legal frameworks such as:

1. The Charter of the United Nations: The Charter establishes the principles of international cooperation and the promotion of peace and security. The ICJ may interpret how this foundational document frames collective action against climate change as a global security threat.

2. The International Covenants on Civil and Political Rights (ICCPR) and Economic, Social and Cultural Rights (ICESCR): These covenants protect fundamental human rights, including the rights to life, health, and an adequate standard of living. The ICJ may assess how climate change undermines these rights and how states must act to prevent such infringements.

3. The United Nations Framework Convention on Climate Change (UNFCCC) and the Paris Agreement: These agreements set obligations for states to reduce greenhouse gas emissions, adapt to climate change, and provide financial and technological support to vulnerable nations. The ICJ may clarify how binding these commitments are under international law.

4. The United Nations Convention on the Law of the Sea (UNCLOS): UNCLOS requires states to protect and preserve the marine environment. The ICJ may explore how this obligation applies to mitigating ocean acidification, sea-level rise, and other climate-related impacts on marine ecosystems.

5. Customary International Law Principles: (i) The Duty of Due Diligence: This principle obliges states to take all necessary measures to prevent harm within and beyond their borders. The ICJ may examine whether states have acted with due diligence in addressing greenhouse gas emissions. (ii) The Principle of Prevention of Significant Harm: States have an obligation to prevent activities within their jurisdiction from causing transboundary environmental damage.

6. The Universal Declaration of Human Rights (UDHR)” The ICJ may analyse how climate change exacerbates the denial of basic rights outlined in the UDHR, including the right to a safe, clean, and sustainable environment.

This question emphasises intergenerational equity, requiring states to consider not just the immediate effects of their actions but also their long-term impact on future generations.

b)        What are the legal consequences under these obligations for states where they, by their acts and omissions, have caused significant harm to the climate system and other parts of the environment, with respect to:

i) States, including, in particular, small island developing States, which due to their geographical circumstances and level of development, are injured or specially affected by or are particularly vulnerable to the adverse effects of climate change?

This sub-question focuses on the disproportionate vulnerabilities faced by certain nations, particularly small island developing states (SIDS). These states are uniquely exposed to rising sea levels, extreme weather events, and loss of biodiversity due to their geographical location and limited resources. The ICJ may determine:

• Whether states responsible for significant greenhouse gas emissions bear legal responsibility for the harm experienced by SIDS.

• How principles like common but differentiated responsibilities (CBDR) apply, recognising the differing capabilities and contributions to global emissions among nations.

• The extent to which states owe compensation or other reparations to SIDS for climate-related damages.

ii) Peoples and individuals of the present and future generations affected by the adverse effects of climate change?

This part highlights the human rights implications of climate change for individuals and communities worldwide. It asks the ICJ to consider:

• The rights of current populations, such as the right to life, health, and property, and how these rights are infringed upon by climate-induced disasters.

• The rights of future generations, invoking the principle of sustainable development and the necessity to preserve environmental resources for posterity.

The ICJ’s advisory opinion on the legal obligations of states regarding climate change could have profound implications for climate litigation at both international and national levels.

• Establishing clear legal precedents for climate litigation: One of the most immediate impacts of the ICJ’s advisory opinion would be the creation of clear legal precedents, particularly in relation to state responsibility and liability for climate change. Climate litigation, at both national and international levels, often revolves around the question of whether states and corporations can be held accountable for contributing to climate change and failing to protect vulnerable communities.

• International Level: The opinion would provide binding legal guidance that could influence international courts and tribunals, particularly in cases where states are accused of breaching their obligations to reduce greenhouse gas emissions or failing to prevent harm caused by climate change. For example, the ICJ’s opinion could set a foundation for holding states accountable in future legal disputes related to climate change impacts that cross borders, like rising sea levels, extreme weather events, and loss of biodiversity.

• National Level: Many national courts have already heard climate cases that invoke international law principles, such as the duty to prevent significant harm and the duty of due diligence. The ICJ’s advisory opinion would provide a more concrete legal framework, empowering national courts to act in alignment with international legal norms. For instance, courts could use the opinion to interpret their own domestic laws more rigorously, strengthening the legal basis for claims against governments and private corporations in cases related to environmental degradation.

• Strengthening climate accountability at national and international levels: The advisory opinion could significantly strengthen the case for holding both states and corporations accountable for their role in climate change:

• State Responsibility: Under international law, states are obligated to ensure that their actions do not cause harm to other states. The ICJ’s ruling could make it clear that countries must take preventive measures to curb greenhouse gas emissions and mitigate climate change effects. This could encourage more national-level litigation aimed at compelling governments to act more swiftly and decisively. National courts could cite the ICJ's opinion as a basis for compelling their governments to fulfil international climate obligations under treaties like the Paris Agreement or the United Nations Framework Convention on Climate Change (UNFCCC).

  
  

• Corporate Accountability: The opinion may also have an indirect effect on corporate responsibility for climate change. While the ICJ’s focus will likely be on state obligations, it could indirectly influence the growing body of climate litigation that targets corporations for their contributions to greenhouse gas emissions. Courts in various jurisdictions may interpret the ICJ’s guidance on state responsibility to impose similar obligations on private actors, particularly those involved in fossil fuel extraction, deforestation, and other environmentally harmful activities.

• Empowering vulnerable states and communities: The advisory opinion could provide legal tools for small island developing states (SIDS) and least developed countries (LDCs) to press claims against more powerful states, particularly those with high historical emissions. These vulnerable states could use the ICJ's findings to demand reparations or compensation for the harms they suffer due to climate change, such as rising sea levels or extreme weather events.

• International Litigation: The opinion could pave the way for more legal actions from vulnerable states in international courts, holding larger emitting nations accountable for damages resulting from climate change. It would help these states demonstrate that their vulnerability is not just a matter of national concern but a breach of international law and collective responsibility.

  
  

• National Courts in Vulnerable States: In countries that are suffering from the adverse effects of climate change, the opinion may enable local courts to invoke international legal principles in climate-related lawsuits. For example, residents in climate-affected areas might pursue national lawsuits demanding government action on emissions reduction or increased climate adaptation efforts.

• Expanding the scope of climate litigation to include future generations: A critical aspect of the ICJ’s advisory opinion could be its affirmation of intergenerational equity, emphasizing the responsibility of states to protect the climate system for present and future generations. This would have significant implications for climate litigation, particularly in regard to claims filed by young people and future generations.

• Intergenerational Equity in Legal Claims: The opinion could provide the legal grounds for expanding the scope of climate litigation to include future generations. Courts could begin to recognise the rights of those who will be affected by climate change in the future, reinforcing claims for the protection of the environment. This would build on existing youth-led climate cases where plaintiffs argue that government inaction today infringes on their right to a liveable future.

  
  

• Legal Innovation in National Cases: National courts may be more willing to grant standing to future generations or non-human entities, such as ecosystems or species, as plaintiffs in climate litigation. This would represent a more radical shift in the application of human rights and environmental law, as courts expand the notion of legal persons to encompass not only individual rights but also the rights of future generations to live in a safe, sustainable environment.

• Encouraging new climate litigation strategies: The ICJ’s advisory opinion could also lead to the development of new strategies for climate litigation, particularly concerning preventative measures. The opinion may emphasize the obligation of states to take proactive steps to reduce emissions and prevent environmental damage before it occurs, shifting the focus from reactive damage claims to prevention-based litigation.

  
  

  • Preventive Litigation: This could open the door for innovative legal arguments aimed at compelling governments to adopt more stringent climate policies, such as legally mandated emissions targets, investment in renewable energy, or implementation of carbon pricing. National courts could use the opinion to issue binding injunctions that force governments to take immediate action on the climate crisis, ensuring that future harm is minimized.

• Climate Policy Reform through Legal Pressure: By interpreting the ICJ opinion, national courts might push for policy reforms at the legislative level. The opinion could serve as a tool for plaintiffs to challenge laws or policies that undermine international climate commitments, urging lawmakers to align national legislation with global climate goals.

The journey to these hearings began with a campaign led by Pacific Island Students Fighting Climate Change, later championed by the small island nation of Vanuatu. Their efforts culminated in the UNGA adopting a resolution in March 2023 requesting the ICJ’s advisory opinion.

Since then:

• The ICJ received 91 written submissions, the most ever for advisory proceedings. These include contributions from nations, international organizations, and environmental groups.

• Written submissions provide diverse perspectives, ranging from legal obligations under specific treaties to the role of equity and justice in addressing climate change.

• The ICJ held consultations with scientific experts, including contributors to IPCC reports, to enhance its understanding of the scientific underpinnings of climate change.

The oral hearings, held from December 2 to December 13, 2024, will feature arguments from nations, regional organizations, and advocacy groups. Key participants include:

• States like Vanuatu, the United States, and China, presenting their views on legal responsibilities for climate action.

• Organizations such as the European Union, African Union, and Alliance of Small Island States, offering regional perspectives.

Following the hearings, the ICJ will deliberate and is expected to issue its advisory opinion in 2025.

The ICJ will livestream the oral hearings on its official website. We will upload daily recaps here on Climate Court.

As the hearings unfold, the world will be watching to see how the ICJ addresses one of the most pressing challenges of our time.