At a landmark legal hearing in The Hague this week, wealthy countries that are big emitters of planet-heating gases have used the Paris Agreement and other existing treaties on climate change to avoid additional pressure to step up their action to tackle global warming. 

Their statements at the International Court of Justice (ICJ) sparked strong criticism from top climate diplomats and advocates who argue that international accords do not place limits on state accountability over climate change. 

The two-week hearing is the culmination of years of campaigning by a group of law students from Pacific nations and diplomacy led by the island state of Vanuatu.  

Their efforts resulted in a UN General Assembly resolution last year calling on the ICJ to provide an advisory opinion on the legal obligations of states to address climate change and the legal consequences if they fail to do so. 

The ICJ says its advisory opinions are not binding. But experts stress that they clarify, rather than create, new law and will be referred to as authoritative documents in future climate litigation and during international climate negotiations. 

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In total, 98 states are giving oral submissions to the court, alongside a handful of institutions including the Organization of the Petroleum Exporting Countries (OPEC).  

Four days into the hearing, a clear divide is emerging between wealthy nations that are historically high emitters and vulnerable nations on the frontlines of climate change that have contributed little to planetary heating. 

The event has seen powerful fossil-fuel producing countries – from the United States to Russia – resist what they regard as an attempt to force them to do more to rein in emissions and provide reparations to those suffering because of their carbon pollution.   

Paris Agreement plans “not sufficient” 

On Wednesday, the United States – which does not fully recognise the authority of the ICJ – told the court that sufficient legal frameworks are already in place to deal with climate change. 

Margaret Taylor, legal adviser to the US Department of State, described global warming as the “quintessential collective action problem” which the UN Framework Convention on Climate Change (UNFCCC) and the Paris Agreement are carefully designed to deal with.  

Those treaties, she said, embody “the clearest, most specific and most current expression of states’ consent to be bound by international law in respect of climate change” – and should therefore be the “primary framework” for determining their obligations. 

Laurence Tubiana, CEO of the European Climate Foundation and an architect of the 2015 Paris Agreement, said in a statement that the landmark pact should not be misused by countries to “dilute their climate responsibilities and accountability”.  

“The Paris Agreement was created as a tool that legally binds countries to display policies and actions, both short and long term, that are consistent with the 1.5C temperature limit,” she said. 

Announcing national climate plans (NDCs) with emissions-cutting targets “that too often do not meet these objectives” – currently the majority – “is not sufficient”, Tubiana added.  

Taylor told the court, on behalf of the US, that the Paris Agreement does not provide any legal standard against which to judge the adequacy of an NDC or to determine if a country is doing its fair share in global terms. Nor do states breach the agreement if they fail to achieve their NDCs, she added. 

Wider international law 

Many countries believe that legal obligations should not be limited to existing climate agreements and have asked the ICJ to consider a wide range of written and unwritten international law, including rules on transboundary harm, due diligence and the duty to cooperate and to prevent harm.  

The relevance and scope of human rights in the context of climate change has also been hotly debated. States particularly disagree over the applicability of the right to a clean, healthy and sustainable environment. This was acknowledged by the UN General Assembly in a 2022 resolution but has proved difficult to implement. 

Mamadou Hébié, associate professor of international law at Leiden University, representing Burkina Faso at the ICJ, said the Paris Agreement does not create any exemption or derogation from the rest of international law. 

Zachary Phillips, counsel for Antigua and Barbuda, said compliance with the Paris Agreement is “necessary but may not be sufficient” to comply with unwritten ‘customary’ international law, including the obligation to prevent harm. 

Several of the world’s biggest economies – among those most reliant on fossil fuels – have contended this week, however, that they have no obligations beyond the Paris pact and the UNFCCC. Australia, for example, said these are “central instruments” for global cooperation while China appealed to the court to avoid “fragmenting” international climate law. 

Call for climate reparations at the ICJ even more urgent after COP29 falls short

Wiebke Rückert, Germany’s director for public international law, said the Paris Agreement strikes a “careful balance” between legal and non-legal commitments and warned that attempts to change that could “seriously” endanger the willingness of states to participate in political processes. 

Ghaida Bajbaa, from Saudi Arabia’s energy ministry, said the UNFCCC provides “no basis whatsoever” for the court to authorise limits to fossil fuel extraction and consumption.  

This was echoed by Maksim Musikhin, director of the legal department of Russia’s Ministry of Foreign Affairs, who said the transition away from fossil fuels – agreed at COP28 in Dubai last year – is not a legal obligation but rather a political appeal. 

Ocean tribunal opinion  

The extent to which state obligations on climate change are limited to the UNFCCC was a key pillar of discussion at the International Tribunal for the Law of the Sea (ITLOS) which this year issued its own advisory opinion on climate change. 

ITLOS ruled that countries need to go beyond their commitments under the Paris Agreement to protect the oceans from the impact of greenhouse gas emissions. The ICJ will have to take this opinion into account, in addition