From COP30 to the courtroom

As Brazil steps off the global stage after hosting the annual UN Climate Conference, COP30, its environmental laws are now testing whether courts can meaningfully assign responsibility for transnational environmental harm.

On 14 November 2025, the English High Court ruled that mining giant BHP was responsible for the 2015 collapse of the Fundão Dam near Mariana, Brazil - Municipio de Mariana & ors -v- BHP Plc & BHP Ltd [2025] EWHC 3001 (TCC). The incident caused catastrophic flooding – leaving long-term ecological and social issues.

The Dam was owned and operated by Samarco Mineração SA (“Samarco”), a Brazilian company jointly owned by Vale S.A. (“Vale”) and BHP Brasil Ltd. BHP Australia is the ultimate parent company of BHP Brasil, and until 2022, operated with BHP UK under a dual-listed structure.

In the English proceedings a claim was brought against BHP UK and BHP Australia (collectively referred to as “BHP”) as they were connected at the time of the collapse. The claim was able to be commenced in the High Court in England & Wales due to the ultimate parent company BHP Group (UK) Limited’s, incorporation in England.

BHP has also confirmed in a statement that it intends to appeal the English High Court decision, arguing that the UK lawsuit duplicates compensation mechanisms already underway in Brazil. There have been numerous proceedings and compensation mechanisms initiated in Brazil and other jurisdictions arising out of the collapse of the Dam, some of which are still ongoing. In 2018, over 600,000 Claimants issued a claim in England and Wales, all seeking compensation in respect of losses suffered, relying on Brazilian Law principles.

Despite the pending appeal, the ruling has implications far beyond a single industrial accident.

Distance is no longer a defence

The BHP judgement is not an isolated event – instead, it is part of the latest in a wave of cases testing the ‘polluter pays’ principle, embedded in international environmental law since the Rio Declaration of 1992. While not directly a climate case, it parallels recent cases focused on parent company liability for past environmental damage (e.g. Kanseche -v- Associated British Foods), or for the potential for future damage based on past actions (e.g. Lliuya -v- RWE AG - the Hamm Higher Regional Court (Oberlandesgericht Hamm) (case I-5 U 15/17) ).

Across these cases, a trend is emerging: courts in wealthy jurisdictions (England & Wales and Germany for example) are increasingly willing to hear claims about environmental and climate harm occurring thousands of miles away.

The Grantham Institute’s Global Trends in Climate Litigation: 2025 report reinforces this. Climate cases are not only increasing in emerging economies; they are becoming more sophisticated. Although new filings have stabilised at roughly 200–250 per year, the field is shifting from quantity to strategic impact.

Key 2025 developments include:

• The Higher Regional Court of Hamm in Germany’s recognition that greenhouse gas emitters can be held liable for their contribution to climate impacts, opening a pathway for attribution science to strengthen nuisance claims.

• The International Court of Justice’s unanimous ruling that states have a legally binding obligation to prevent significant harm to the climate system and ruling that access to a safe Earth system is a human right.

• The English High Court finding that BHP were strictly liable as “polluters” in respect of damaged caused by the collapse of the Fundão Dam. With over 600,000 Claimants, each seeking compensation in respect of losses suffered, the damages will be substantial. Subject to BHP’s appeal, a trial of the quantum issues, where the court will determine the damages to be awarded, is set for 2026.

These are foundational shifts in moving climate and environmental action from the negotiating table to the court room.

Governance failures as environmental harm

Whether the case concerns a dam collapse in Brazil or climate-driven glacial melting in Peru, courts are converging around key expectations of corporate behaviour: robust oversight management of foreseeable risks and responsibility for downstream impacts.

The BHP case underscores this trend. Companies can no longer rely on local regulatory gaps in enforcing the polluter pays principle, such as voluntary environmental remediation commitments in the UK, to shield themselves from liability. Nor can the use of subsidiary companies in other jurisdictions prevent liability for parent or holding companies. Where parent/holding companies are exerting significant control and management over subsidiaries and deriving substantial benefits from the same, they can be held liable of the actions of their subsidiaries.

As attribution science advances, the legal exposure widens. Courts can increasingly link corporate actions (or inaction) to quantifiable harm, even across borders. This strengthens the argument that failure to mitigate emissions, disclose climate or environmental risk, or prevent foreseeable climate impacts constitutes a breach of duty which may ultimately lead to a significant award of damages.

The rise of class actions and community-led claims

Another defining feature of this moment is the surge in group/class actions and community-led environmental rights cases. This is particularly salient in Latin America, where constitutional protection of environmental rights is widespread, and where indigenous communities are playing a leading role in redefining environmental justice. The BHP case is reported to be the largest group claim in UK history (£36 billion) and the judgment (if upheld on appeal) sets a major precedent for holding multinational companies accountable in the English courts for environmental harm overseas.

Indigenous groups across Brazil and the wider Amazon basin have increasingly demonstrated that environmental harm is not only ecological but cultural, intergenerational, and existential.

In England & Wales, there is no U.S.-style opt-out class action system. Instead, large claims are managed through either Group Litigation Orders (GLOs) under Civil Procedure Rules (CPR) 19 or Representative Actions which are rarer (CPR 19.6). A GLO allows multiple claimants with common or related issues to join in a claim under one procedural umbrella, but each claimant remains individually named.

With over 600,000 claimants (individuals, businesses, municipalities, indigenous groups), the common issue in the BHP case was the liability of BHP for the Fundão dam collapse under Brazilian law. The claim proceeded as a GLO-style proceeding, with a lead case (Municipio de Mariana & Ors) to determine key liability questions (Stage1). All other claims were stayed pending the outcome of Stage 1.

The claimants were successful in establishing liability at Stage 1 and the claim will now (subject to any appeal) proceed to a Stage 2 Trial which will address causation and quantum for all claimants collectively. The findings on common issues from Stage 1 apply to all registered claimants although each claimant will still need to prove their own specific losses at Stage 2.

The case illustrates how the English courts handle mass torts without a formal class action statute, and are also willing and able to apply foreign law (Brazilian environmental law) in English proceedings.

In terms of enforcement, after Stage 2 is completed and damages awarded there will be in existence an English money judgment that will automatically be enforceable against any of BHP’s assets in England & Wales. Further, there are various means of enforcing an English Judgment outside the UK under the Administration of Justice Act 1920 and Foreign Judgments (Reciprocal Enforcement) Act 1933 which include enforcement against assets in countries such as Australia, New Zealand and India or separately via reciprocal enforcement treaties e.g. with Singapore and Malaysia. The geographical reach of the enforcement of an English judgment is wide.

COP30 Context: Tipping points and human rights in the legal landscape

COP30 concluded with a final document that reaffirmed previous commitments but did not meet the heightened ambition many expected, given escalating planetary risks. As multilateral negotiations face growing scrutiny and struggle to deliver transformative outcomes, attention is increasingly turning to legal accountability as a mechanism to bridge the gap.

The realities of approaching temperature overshoot and the increasing likelihood of reaching climate tipping points and doing irreversible damage to ecosystem services are shaping litigation: courts increasingly recognise that foreseeable risks, when ignored, constitute failures of duty.

Who pays for loss and damage?

Cases like BHP, RWE, and Malawi v ABF all centre on a common theme: environmental and climate harm disproportionately affects poorer and more vulnerable communities. These cases raise urgent questions about responsibility, restitution, and the financing of loss and damage.

This legal movement parallels policy developments within the UNFCCC, including:

• the operationalisation of the Loss and Damage Fund

• debates over international carbon levies such as the IMO shipping tax

• emerging frameworks for ecological compensation.

Courts are increasingly willing to trace causal links between corporate behaviour and community-level harm, whether through pollution, supply-chain practices, or historical emissions.

Towards a transnational duty of care

The broader direction of travel is clear: an enforceable transnational environmental duty of care is emerging. There may be jurisdictional considerations and the necessity for the courts to apply the law of a country that is not their own but these issues are not insurmountable as the BHP case illustrates.

As Brazil transitions from COP host to legal test case, the world is watching how courts, science, Indigenous leadership, and financial mechanisms will converge to shape the next chapter of climate and environmental accountability.