From Principle to Obligation: ICJ’s Opinion on Climate Change and Implications for African Countries

What happens when the world’s highest court declares climate change not just a political challenge but a matter of international law? On 23 July 2025, the International Court of Justice (ICJ) issued a landmark advisory opinion that could redefine the global climate order. The momentum for this case began with a youth-led global campaign spearheaded by Pacific Islands Students Fighting Climate Change (PISFCC) and World’s Youth for Climate Justice (WYCJ). They mobilized more than 1,500 civil society groups worldwide and successfully persuaded the United Nations General Assembly to adopt the resolution requesting the advisory opinion. The government of Vanuatu successfully led a coalition of 132 nations that secured the consensus adoption of a UN General Assembly resolution calling for the advisory opinion. The resolution sought to clarify states’ legal obligations under international law to protect the climate and environment from anthropogenic greenhouse gas emissions, and to determine the legal consequences for states whose actions or omissions cause significant harm to vulnerable nations and future generations. For the first time, the world court confirmed that countries failing to mitigate or adapt adequately could face legal accountability. Although not formally legally binding, ICJ advisory opinions strongly influence states, legislation, and courts by clarifying international law and shaping emerging customary norms. For African countries, which are least accountable for emissions but most severely affected, the ruling creates both opportunities to advance claims for justice and to secure international support, as well as responsibilities to strengthen domestic climate action.  

International Leverage and Legal Obligations

The ICJ opinion bolsters Africa’s hand in international negotiations and disputes. By reaffirming that climate treaties and general international law create obligations (not mere promises), African governments can more forcefully insist that wealthier emitters fulfill their duties. It rejected arguments by some major powers that climate treaties like the Paris Agreement are “lex specialis”, excluding other law – instead, the court affirmed that general principles of international law also apply to climate obligations. In practical terms, every country now has a clarified duty to prevent significant environmental harm by taking all reasonable measures to reduce greenhouse gas emissions and protect the climate system. The judges emphasized that inaction can breach international law, which means that climate responsibility is a legal duty for all states, not a mere policy choice. This implies that failing to adopt necessary climate measures or allowing dangerous emissions constitutes an internationally wrongful act with potential legal consequences under international law.

This legal backing gives African governments and civil society a basis to demand climate action and support from major emitters. They can hold both foreign polluters and their own governments accountable. Likewise, African NGOs and courts can invoke the ruling in domestic cases or before the UN. The Court explicitly linked climate duty to human rights, and it declared that a clean, healthy environment is essential to rights such as life, health, food, and water. This “rights-based” framing vindicates African campaigns that portray climate disasters as violations of basic rights. By interpreting climate obligations as obligations owed to all humanity, the ICJ opinion recognizes that Africa’s well-being matters globally. The advisory opinion can be cited in multilateral negotiations to demand more ambitious targets and to support them. It can also guide African delegations to insist on explicit language about human rights, equity, and compensation in climate agreements. 

Legal Obligations to Finance and Bridge the Technology Gap

One of the most consequential aspects of the ICJ opinion is that African governments and communities now have a firmer legal footing to demand climate finance and technology support. The ICJ opinion makes clear that wealthy countries’ commitments to assist developing states are binding duties, not voluntary acts of charity. In affirming the UNFCCC and Paris Agreement obligations, the Court underscores the duty of cooperation, particularly in terms of financing, technology transfer, and support for the most vulnerable countries. This means that mechanisms like the Green Climate Fund, adaptation funds, and other international climate finance commitments, according to the Court’s reasoning, are not acts of charity but grounded in legal obligation. The ICJ reaffirmed, consistent with Article 4(4) of the UNFCCC, that developed countries bear additional obligations to lead global climate action by providing financial and technological support.

Long-standing goals – such as the $100 billion per year climate finance pledge – gain stronger legal backing, potentially pressuring donors to deliver on and scale up these commitments. It took until 2022 for developed nations to even meet the $100 billion target, and they did so only two years late, at about $115.9 billion. The advisory opinion supports African negotiators’ calls for far more ambitious post-2025 finance commitments. The opinion also affirms that contributions to funds such as the Loss and Damage Fund do not replace states’ legal duties of reparation but rather complement them. Furthermore, the ruling empowers African governments and regional blocs to press donors for predictable and scaled-up funding. African negotiators can unite through the African Union and regional bodies to align their positions and increase their influence in global climate negotiations.

The ICJ opinion also solidifies Africa’s entitlement to climate-related technology and expertise. It aligns with Article 4.5 of the UNFCCC and Article 10 of the Paris Agreement, which obliges developed countries to share environmentally sound technologies. The Court makes clear that bridging the technology gap is no longer optional; it is part of the duty to combat climate change. African institutions can now request the removal of barriers, such as intellectual property restrictions on green tech, or seek co-financing for clean energy infrastructure. For example, nations can use ICJ precedents when negotiating under the UNFCCC’s Technology Mechanism to secure better terms for solar, wind, battery storage, and climate monitoring technologies. Capacity-building is similarly emphasized and developed countries must not only fund equipment but also train African experts and strengthen domestic systems, so that climate solutions can be implemented and maintained locally. Already, new partnerships such as Just Energy Transition Partnerships (JETPs) combine funding with technical roadmaps; the advisory opinion suggests such initiatives should expand and become standard practice.

Domestic Responsibilities and Energy Transition

While the ICJ opinion empowers Africans on the international front, it also places new responsibilities on African governments at home. The ICJ made it clear in the advisory opinion that “States have a duty to prevent significant harm to the environment by acting with due diligence and to use all means at their disposal to prevent activities carried out within their jurisdiction or control from causing significant harm to the climate system and other parts of the environment in accordance with their common but differentiated responsibilities and respective capabilities”. 

African countries can no longer justify unrestrained fossil-fuel expansion solely on the grounds of development needs. In fact, the Court explicitly warned that continuing fossil fuel extraction without appropriate climate action may constitute an internationally wrongful act. Licensing new coal mines, oil wells, or pipelines without climate safeguards could now expose African states to legal challenges. African countries that are still expanding fossil fuel production are at a crossroads, as this poses a challenge for them when they advocate for climate justice abroad, whilst expanding fossil fuel production at home.

Thus, African governments bear the obligation to integrate climate risk assessments and due diligence into all development decisions. Before approving new energy or mining projects, governments may now be expected to conduct climate-specific environmental impact assessments. These would evaluate whether a project is compatible with the 1.5°C target and the country’s own NDC (national climate plan). The 1.5°C target was breached in 2024 and now serves more as a reference for national planning and accountability.

Conclusion: Recasting Climate Policy and Justice as a Legal Imperative

The ICJ’s advisory opinion marks a decisive moment for Africa to turn legal recognition into transformative action. It recasts climate justice as both a right and a duty, compelling governments, regional bodies, and international partners to act with urgency and accountability. African states must leverage the ICJ opinion’s authority to advance claims for finance, technology, and loss-and-damage reparations – now backed by legal obligation, not moral appeal. This means uniting under the African Union and regional blocs to negotiate higher, enforceable post-2025 finance targets, demand equitable access to clean technologies, and insist that capacity-building commitments translate into tangible institutional reforms.

At home, African leaders must operationalize the ruling by embedding climate due diligence into law, integrating the “no harm” principle across all energy and development decisions, and aligning national plans with the 1.5°C pathway. However, a major challenge persists; many of the same governments that advocate for climate justice abroad continue to expand fossil fuel exploration and infrastructure domestically. New oil, coal, and gas projects risk undermining Africa’s moral authority in global negotiations and could constitute breaches of climate due diligence obligations under international law. Reconciling these tensions requires transparent transition strategies that link energy security, employment, and development goals with credible decarbonization pathways.

Dr Phemelo Tamasiga is an Associate at Megatrends Afrika and a Researcher at the German
Institute of Development and Sustainability (IDOS).

Prof Helen Onyeaka is an Associate Professor at the University of Birmingham, Deputy Director of Birmingham Institute for Sustainability and Climate Action, an expert in food safety, microbiology, and sustainable food systems.