knowledge 23 March 2026 |

The Evolving Landscape of Global Climate Change Litigation: Perspectives for 2026

ICJ Advisory Opinion on the Obligations of States in respect of Climate Change

On 23 July 2025, the International Court of Justice (“ICJ”) delivered its unanimous Advisory Opinion on the Obligations of States in respect of Climate Change.  Significantly, the ICJ found that countries’ international law obligations are not limited to those agreed to under climate treaties (such as the Paris Agreement), but stem also from duties under both human rights and customary international law. The ICJ also found that failure to comply with those obligations could expose countries to concrete legal risks.

The ICJ decision is an advisory opinion. It is not directly enforceable against countries, and by itself, imposes no legal consequences. However, the opinion carries substantial legal and political weight and sets out a roadmap that could guide future litigation before international tribunals and domestic courts in 2026 and beyond.

Corporate Accountability

According to the Sabin Centre for Climate Change Law globally around 20% of climate cases filed in 2024 targeted companies or their directors and senior officers.  Some of the more significant decisions in this area include Milieudefensie et al. v Royal Dutch Shell where the Dutch Court of Appeal found Shell owed a private duty of care under the Dutch Civil Code to reduce CO2 emissions.  The case is currently under appeal with Milieudefensie seeking reinstatement of the previous order which required Shell to reduce its aggregate annual CO2 emissions by a specific percentage namely, at least 45% by 2030 compared with 2019 levels.

In May 2025, the Higher Regional Court of Hamm delivered its judgment in Luciano Lliuya v RWE addressing the legal responsibility of RWE for alleged property damage in Peru as a result of climate- change induced glacial melting.  While the court dismissed the claim brought by Peruvian farmer Saúl Luciano Lliuya against RWE, the country’s largest greenhouse gas emitter, most significantly, the court held that—at least in principle—companies responsible for large-scale emissions can be held liable under German civil law for the climate-related harms they contribute to.  The court accepted attribution science (which determines causal responsibility for the drivers and impacts of climate change) and rejected RWE’s argument that its contribution was a drop in the ocean or too minor to matter.

As methods of attribution science grow more precise, and with the courts increasing willingness to accept attribution science, legal exposure for emitters is likely to increase.  However, while we have seen increasing judicial acceptance of attribution science, in our view a key legal challenge remains in linking specific emitters to quantifiable climate harm, which will we suspect continue to be one of the greatest challenges to the successful pursuit of corporate accountability for climate change in 2026.

Human rights-based litigation

The role of human rights is becoming increasingly prominent as adverse impacts of climate change become more evident.  In April 2024, the European Court of Human Rights handed down judgment in KlimaSeniorinnen and Others v Switzerland, ruling that Article 8 of the European Convention on Human Rights (the “Convention”) encompasses a right to effective protection by the State authorities from the serious adverse effects of climate change on lives, health, well-being and quality of life and that Switzerland had failed to comply with its positive obligations under Article 8 of the Convention.

Notably it was the NGO applicant that was held to have standing to litigate the case before the European Court of Human Rights, in contrast to the position previously taken by the Irish Supreme Court where in Friends of the Irish Environment v the Government of Ireland they found that Friends of the Irish Environment did not have the requisite standing to advance rights-based arguments.

As a result of the KlimaSeniorinnen judgment it seems likely that for cases in 2026 the Convention will have a much more prominent role to play in the field of Irish climate law, and that the Supreme Court will be asked at some stage to revisit its previous finding in relation to NGO standing.  A challenge to the Climate Action Plan 2024 by the Community Law and Mediation Centre is currently pending before the High Court.  

Greenwashing

Greenwashing and broader ESG related misrepresentation claims remains the fastest-growing strategic category of litigation, and the fundamental risk area for businesses.  In our view, this will not change for 2026.   

With the European Commission announcing the withdrawal of its proposal for a Green Claims Directive on 20 June 2025, one could be forgiven for querying what that means for the future of the law on green claims.  However, the abandonment of the Green Claims Directive does not mean that green claims go unregulated.  At an EU level, the Empowering Consumers for the Green Transition Directive amends two existing consumer law directives: the Consumer Rights Directive and the Unfair Commercial Practices Directive and introduces several specific new prohibited and misleading commercial practices provisions relative to “green claims”.  Member States are required to transpose the Directive by 27 March 2026, while from 27 September 2026 it enters into application.  While the Department of Enterprise Trade and Employment previously indicated its intent to meet this transposition deadline, with the deadline now looming, it is unclear whether it will indeed be met.

Conclusion

Claimants are increasingly employing novel strategies to establish legal liability for climate-related harm, drawing on causes of action grounded in tort, human rights, and public law. Our 2026 predications include:

• The ICJ Advisory Opinion, albeit non-binding, will likely be influential in guiding future climate litigation before international tribunals and domestic courts. 
• Large emitters will remain vulnerable to climate claims in 2026 particularly given a discernible willingness of courts to accept attribution science.  However, notwithstanding this willingness, establishing a causal connection between specific emitters and quantifiable climate harm will in our view remain one of the greatest challenges to the successful pursuit of corporate accountability for climate change in 2026.
• Following the April 2024 decision of the European Court of Human Rights in KlimaSeniorinnen and Others v Switzerland, allegations of a failure to comply with the Convention will take a much more prominent role in domestic climate litigation.
• We will continue to see an increase in greenwashing and broader ESG related misrepresentation claims.