In the early weeks of December, nearly 100 countries and 12 international organisations presented oral arguments before the International Court of Justice (ICJ) at The Hague, on the question of the legal responsibility of states when it comes to climate change. The Court is being asked to issue an opinion on what the legal obligations are of States to safeguard the climate system from GHG emissions, and what the legal consequences are when these emissions cause significant harm.
Each country, regional group and organisation that made written submissions was invited to make 30 minute statements, with hearings spanning 2-13 December 2024. These accompanied the largest set of written proceedings the court has ever witnessed, with 91 written statements filed in its registry, together with 62 written comments on these statements. The African Union made a regional submission, with individual state submissions submitted by the Democratic Republic of the Congo, Tonga, Sierra Leone, Namibia, Madagascar, Cameroon, Ghana, South Africa, Mauritius, Egypt, Kenya, Seychelles, The Gambia, and Burkina Faso.
The case was lead by the Pacific island nation of Vanuatu, who were able to persuade members of the UN General Assembly to pass a resolution calling for an advisory opinion from the ICJ in 2023. Although not itself legally binding under international law, the advisory opinion will likely be cited in climate lawsuits around the world, including in regional and national courts, and would carry strong precedential weight before any judge.
Strategically, any opinion by the court whether in favour of developing or developed states, would likely also influence negotiators. The direction in which it does depends on what the court finds, but if, for example it supports the payment of climate damages, it could strongly influence loss and damage negotiations, and may make historic emitters more amendable under threat of judicial proceedings. As the delegation leader for St Lucia, Jan Yves Remy, pointed out, “We’re not getting anywhere in the negotiations…What do we have to lose?”
The question before the court is not narrow. The request for an opinion asks the court to consider the full suite of international law, including both treaty law like the Paris Agreement and UNFCCC, as well as “customary international law” and how it applies to all states across the world in a myriad of different contexts. Customary international law can be especially tricky to pin down as it requires a determination of whether there is a general and consistent practice by States which they follow out of a sense of legal obligation, thereby establishing a customary rule. One example is the legal duty of one state not to cause “significant harm” by its domestic actions to another. But customary international environmental law is still murky. There are few cases to rely on and state practice can be inconsistent. For instance, it has been debated whether there is an international customary rule or duty to protect the climate system, whether there is a human right to the environment, and whether principles like sustainable development, common but differentiated responsibilities and respective capabilities (CBDRC), and intergenerational equity have reached the status of customary international law.
When appearing before the courts, unsurprisingly developed countries and some petro-States like OPEC, argued that the Paris Agreement and UNFCCC encapsulate the primary legal obligations on climate change and address the full scope of any related liability. In other words there is no scope to create additional duties outside of these treaties based on customary international law. Some emerging economies like India and South Africa seemed to agree with this approach. The United States also kicked up dust around the uncertainty of the science when it came to pin-pointing liability and establishing causation. China echoed this arguing that it was extremely difficult to establish a causal link between specific GHG emissions and any loss and damage a State might suffer, and then to further quantify the loss.
The African Union, together with most developing countries however argued that customary international law went beyond existing treaty law, calling out attempts by the UK, China, OPEC and the US to downplay the role of climate science. They asked the court to recognise that States have preventative duties under customary international law not to harm the climate system. This can take multiple forms but included:
- a duty of states to take measures and develop the necessary rules in light of scientific evidence e.g. by adopting legal and other measures to reduce GHG emissions;
- a duty to undertake impact assessments and identify risks (e.g. when granting new oil and gas licences),
- a duty between states to cooperate in good faith, for example by notifying and consulting with states when authorising large scale GHG emitting activities;
- the duty to exercise a level of vigilance by monitoring the activities of public and private operators;
- a duty to take into account international rules and standards, for example the International Civil Aviation Organisation’s net zero target.
The AU also argued that States have a customary international law “due diligence” duty to urgently phase out fossil fuels and ensure a just transition. There is also a duty to allocate the burden of emissions reductions asymmetrically and fairly between them. All high emitters are included in this group both past, e.g. the US, and present, e.g. China, and irrespective of whether they have high emissions per capita, or if they have high emissions overall, acknowledging that a spectrum of factors such as past, present and future projected emissions as well as technical and abatement costs that inform the nature of this duty (i.e. the principle of CBDRC). The group also argued for the recognition of the principle of intergenerational equity. Multiple other developing countries also argued for recognition of the integral relationship between climate change and the realisation of human rights, such as the right to self determination, and the right to life.
The AU also enjoined the court to reject the argument by developed countries that there is no state liability for GHG emissions, and to rather recognise the conduct as wrongful, triggering the need for legal consequences such as restitution or reparations.
And that’s really what the proceedings are about. The scope of reparations a national or regional court could issue has the potential to be economically devastating. Which is why African countries were quick to offer alternative forms. The AU, Kenya, Sierra Leone, Namibia, and Malawi argued that partial or total debt cancellation could be a valid form of compensation. Kenya and Malawi also suggested that support for adaptation, including the transfer of resources and technology, could be a form of compensation.
The task of the ICJ is unenviable. The expanse of the arguments and the sheer volume of the submissions are vast, and the gravitas of its findings on the direction of future litigation will be profound. Its 15 member bench is well represented by developing countries including African states, with its Vice President Julia Sebutinde from Uganda, and two other judges from Somalia and South Africa. The court is due to make a ruling during the course of 2025.
