Globally, there is a steady rise in the use of litigation to seek redress for climate-related harms and a reduction in emissions. To succeed, lawyers must work with climate scientists, as developments in attribution science are making climate-related claims increasingly viable.  

A common factor in any jurisdiction is the need to establish causation between the defendant’s acts and the harm suffered by claimants. Many past claims have failed due to inadequate scientific evidence and/or the poor judicial treatment of it.

A 2021 study, which examined the scientific and legal bases for establishing causation and the judicial treatment of scientific evidence in 73 climate-related lawsuits [1], found that the evidence used to support these claims lagged considerably behind the climate science available at that time, impeding their ability to establish causation. The conclusion was that greater appreciation of attribution science among legal scholars and practitioners could make it easier to establish causation in climate-related claims, thereby improving the prospects of success.

Recent developments in attribution science

Studies in the scientific field of attribution science typically linked events such as heatwaves or floods to climate change in general, without identifying specific contributors. However, research published in Nature in September 2025 demonstrated that scientists are now able to link the emissions of specific corporations to specific climate-related events [2].

The research focused on ‘carbon majors’, a database of the 180 largest fossil-fuel and cement producers. The research analysed their emissions from 1854 to 2023, assessed how they contributed to global mean surface temperature and how this affected the probability and severity of 213 historical heatwaves across the world.

The research concluded that carbon majors have contributed to approximately half the increase in heatwave severity since preindustrial times. Emissions from the largest emitter, the former Soviet Union, made 25% of the heatwaves assessed 10,000 times more likely, and even the smallest emitter made 8% of them 10,000 times more likely. It concluded that without these emissions, it is virtually impossible that these heatwaves would have occurred. Moreover, this approach can be adapted to analyse other climate-induced events.

The ability to link corporate emissions to specific climate-related events marks a pivotal shift in both scientific and legal practice areas.

Application to climate litigation

These scientific advancements coincide with an incremental acceptance by judicial authorities that, at least in principle, corporates can be held accountable for climate-related events. On 23 July 2025, the International Court of Justice (ICJ) provided an advisory opinion recognising that although causation in climate litigation is complex, it is not impossible to overcome [3].

The ICJ assessed that the current legal standard for establishing causation under international law was that there must be “a sufficiently direct and certain causal nexus between the wrongful act… and the injury suffered”. This aligns with domestic approaches, such as the UK’s ‘but for’ test, which requires a complete causal chain between conduct and harm. The ICJ’s

opinion was that attribution science can be applied to climate litigation. Although not binding on domestic courts, it is likely to be relied upon as a persuasive statement of international law in the context of climate litigation.

Recent litigation trends reflect this. Since 2021, the number of successful climate-related claims has increased globally. In 2024, corporate defendants featured in 14% of apex court climate cases, and over half of those resulted in positive climate outcomes [4]. A steady raft of further claims, many relying on attribution science, are progressing through courts internationally.

A significant example was the New Zealand Supreme Court’s February 2024 ruling that a claim brought by an elder of two Maori tribes and climate change spokesperson for the NZ national forum of tribal leaders, against a group of companies alleged to be responsible for one-third of New Zealand’s greenhouse gas emissions, should proceed to trial (Smith v Fonterra & Others [5]). The claim asserts a novel ‘climate system damage’ tort, and seeks declarations of unlawfulness and injunctions requiring net-zero emissions by 2050. It is currently proceeding through the courts.

In 2025, German courts, although ultimately rejecting the claim of a flood-stricken Peruvian farmer against energy giant RWE, found that, in principle, a defendant’s contribution to global emissions could translate into accountability for a single weather event [6]. In the same year, the US Supreme Court refused an attempt by Sunoco to strike out a claim alleging that it misled the public for decades about the impact of burning fossil fuels [7].

In the UK, survivors of Typhoon Odette, which struck the Philippines in December 2021, initiated legal proceedings against Shell by a pre-action letter in October 2025. They will seek damages, including for serious property damage, bereavement and loss of earnings. Relying on a recent attribution science study, which found that anthropogenic climate change (‘ACC’) “more than doubled the likelihood of a compound event like Typhoon Odette” [8], they argue that Shell’s emissions materially contributed to ACC intensifying Typhoon Odette, and that despite knowing for decades that fossil fuels drive climate change, Shell continued to increase its emissions between 1965 and 2021.

Continuing challenges

Despite these advancements, these claims remain challenging. Attribution science is still developing, and effective presentation of such complex scientific evidence is a significant task, particularly when faced with opposing opinions from defendants’ scientific experts. If climate scientists and lawyers cannot work together to help judges understand their analysis, the value that attribution science can bring will be undermined.

Even where causation can be established, that is just one element. Claimants must also show that defendants owed a duty of care, potentially requiring an examination of historical scientific understanding of the impact of emissions.

For those who succeed, further application of the science may be required to consider the remedies sought, whether to demonstrate the extent of a defendant’s contribution to the harm suffered and, therefore, their proportional liability for monetary damages or to show what impact other orders requiring defendants to change their emissions plans would have on reducing future harms.

Conclusion

If legal practitioners and climate scientists collaborate effectively, integrating developing attribution science into judicial processes could transform the prospects of climate-related claims, not only in the UK but across the world.

If that occurs, major corporate polluters need to be alive to the prospect of a new era of scrutiny and accountability for historical and ongoing contributions to climate change.

This article was first published on the BusinessGreen website: https://www.businessgreen.com/opinion/4528821/evolving-role-climate-attribution-science-legal-action-corporates

References

1. Filling the evidentiary gap in climate litigation; Rupert F. Stuart-Smith, Friederike E.L. Otto, Aisha I. Saad, Gaia Lisi, Petra Minnerop, Kristian Cedervall Lauta, Kristin van Zwieten & Thom Wetzer
2. Quilcaille, Y., Gudmundsson, L., Schumacher, D.L. et al. Systematic attribution of heatwaves to the emissions of carbon majors. Nature 645, 392–398 (2025). https://doi.org/10.1038/s41586-025-09450-9
3. ICJ’s landmark climate opinion: what it means for business
4. LSE Grantham Institute: Global-Trends-in-Climate-Change-Litigation-2025-Snapshot.pdf
5. SC 149/2021 [2024] NZSC 5
6. Luciano Lliuya v RWE
7. City and County of Honolulu et al v Sunoco LP et al