From climate change to the deep sea: reflecting on a milestone year in international environmental law, and implications for private practice

2025 was a milestone year for international environmental law and policy, marked by advisory opinions on climate change from the International Court of Justice (ICJ) and the Inter-American Court of Human Rights (IACHR) and the Agreement on Marine Biological Diversity of Areas beyond National Jurisdiction (BBNJ Agreement) reaching sufficient ratifications to enter into force. Against this backdrop, in December the IBA Environment, Health and Safety Law Committee – supported by the IBA Maritime and Transport Law Committee, IBA Water Law Committee and IBA Legal Policy & Research Unit – convened a webinar to reflect on key advances in climate litigation, multilateral environmental negotiations and emerging treaty regimes and to assess their implications for private legal practice.

The discussion, which was moderated by Els Reynaers and Bill Kritharas (Co-Chairs, IBA Environment, Health and Safety Law Committee), was structured around three interconnected segments:

• key developments in climate litigation and policy, including reflections on COP30;
• the state of negotiations towards an internationally binding instrument on plastic pollution; and
• private sector implications of the new BBNJ Agreement, which will take effect in early 2026.

This article summarises highlights from the conversation. Watch a recording of the webinar here.

Preventive climate litigation: how courts are shaping climate accountability

Opening the conversation, Wilhelm Bergthaler (Partner, Haslinger Nagele Rechtsanwälte; Member, IBA Environment, Health and Safety Law Committee Advisory Board) reflected on what he described as a ‘bountiful harvest’ for climate litigation in 2025. Drawing on recent advisory opinions and judicial decisions, he observed that international climate jurisprudence is gradually but surely developing a coherent framework that leaves no escape route for states or major emitters.

As Wilhelm observed, central to this shift is the ICJ Advisory Opinion on the Obligations of States in respect of Climate Change, which confirms that climate change obligations are embedded in customary international law, independent of treaty participation. States cannot evade responsibility by withdrawing from climate agreements; they retain duties to prevent significant environmental harm and to cooperate internationally. This finding, Wilhelm noted, sends a clear message to both governments and carbon-intensive industries.

Wilhelm also highlighted that the IACHR Advisory Opinion on the Climate Emergency and Human Rights goes further by translating these obligations into individual and collective rights, including the right to a healthy environment, enhanced protections for indigenous and local communities and procedural rights such as access to justice, political participation and even a human right to science. The recognition of traditional and indigenous knowledge, he argued, marks a significant evolution in how courts assess environmental harm and evidence.

Drawing on contemporary case law including the recent Lliuya v RWE litigation before German courts, Wilhelm observed that claimants are increasingly resorting to litigation to seek preventive relief from both states and corporations before irreversible climate-related harm occurs.

Looking ahead, Wilhelm queried whether established environmental liability regimes (such as those for asbestos and PFAS) may inform future approaches to climate liability, and foreshadowed that climate litigation will continue to expand as scientific knowledge solidifies and courts refine rules on responsibility and causation.

The ‘Implementation COP’: COP30 concludes with new private sector initiatives   

Moving to explore the outcomes of UNFCCC COP30, which concluded last month in Belem, Maria Cristina Breida (Partner & Environment, Climate Change & Sustainability Leader, EY Tax & Law, Italy; Vice Chair, IBA Environment, Health and Safety Law Committee) and Beatriz Frontin (Partner, Veirano Advogados, Brazil) offered an in-depth assessment of the conference, which took place amid escalating climate impacts, geopolitical tensions and heightened expectations for implementation.

Maria Cristina observed that while COP30 fell short of securing consensus on fossil fuel phase-out language in the final outcome decision, it marked progress in other areas. Indigenous peoples and local communities were recognised more prominently than ever before, and the summit generated a range of voluntary initiatives involving states, cities and the private sector. Brazil committed to launch voluntary roadmaps on fossil fuel transition and deforestation outside the UN process, thereby keeping political momentum alive despite negotiation deadlock. Beatriz emphasised that the visibility and participation of indigenous communities at the conference underscored the growing integration of human rights with climate governance, and mirrored the rhetoric articulated by the ICJ and IACHR in their recent advisory opinions.

Maria Cristina noted that COP30 also advanced discussions on adaptation finance, calling for a tripling of funding by 2035, and introduced mechanisms including the Belém Mission 1.5 and a Global Implementation Accelerator to bridge the gap between existing nationally determined contributions (NDCs) and the 1.5°C temperature goal of the Paris Agreement. Trade emerged as a central theme, with explicit recognition of the intersection between climate policy and trade measures, including concerns around carbon border adjustment mechanisms. The creation of a Just Transition Action Mechanism marked a significant step, providing a platform to coordinate support for workers and communities affected by the shift away from fossil fuels.

Maria Cristina also highlighted several initiatives of particular relevance for the private sector, such as the Belém Declaration on Global Green Industrialisation, the Open Coalition on Compliance Carbon Markets, and commitments to scale up sustainable fuels for hard-to-abate sectors. While not all outcomes were binding, they reflect a shift toward coalition-based implementation, with direct implications for corporate strategy and legal compliance.

Beatriz highlighted that international climate governance is increasingly being driven through coalitions, voluntary commitments and sectoral alliances, complementing the UNFCCC’s formal multilateral consensus process. She highlighted that for private practitioners in Brazil, key developments to watch in the wake of COP30 include the implementation of Brazil’s Greenhouse Gas Emissions Trading System and the interaction between climate litigation, human rights claims and corporate permitting processes.

The UN Plastics Treaty: ambition, deadlock and alternative pathways

The second segment of the webinar turned to ongoing efforts to agree an internationally binding instrument on plastic pollution, with Dr Alexandra Harrington (Chair, World Commission on Environmental Law Agreement on Plastic Pollution Task Force, International Union for Conservation of Nature) tracing the process from its origins in the 2022 UN Environment Assembly to the stalled negotiations in Geneva in August 2025 after five formal negotiating sessions.

Alexandra clarified a persistent misconception: the treaty is not intended to ban plastics per se, but to address plastic pollution across the full lifecycle. Despite strong political ambition, divisions persist over lifecycle regulation, financing mechanisms, extended producer responsibility and procedural rules such as consensus versus voting.

Alexandra noted that the failure to conclude negotiations on schedule has resulted in procedural uncertainty, including the resignation of the Intergovernmental Negotiating Committee (INC) Chair and the prospect of further negotiating sessions in 2026. She outlined three possible paths forward: continued negotiations within the INC framework, pursuing an agreement outside the UN system (as with landmines and cluster munitions) or relying on existing multilateral environmental agreements, though she cautioned that the latter option is legally complex.

For private practitioners, the Plastics Treaty illustrates the fragmented and experimental nature of contemporary environmental governance, where regulatory risk may arise even before binding instruments are finalised.

A milestone year for ocean governance: what will the new BBNJ Agreement mean for private practitioners?

The final segment of the webinar focused on the BBNJ Agreement, which will enter into force in January 2026, having reached its threshold ratifications for entry into force in 2025.

Anika Havaldar (Senior Associate, Freshfields, Dubai) provided an overview of the treaty’s structure, highlighting its four substantive pillars: marine genetic resources (MGRs), area-based management tools (including marine protected areas), environmental impact assessments (EIAs) and capacity-building and technology transfer. While the treaty imposes obligations on states, she emphasised that its implementation will rely heavily on domestic legislation and may go beyond the treaty’s minimum standards, directly affecting private actors.

Anika noted that the treaty introduces novel mechanisms for notification, benefit-sharing and monitoring of MGRs, internationalises EIAs on the high seas and enables the adoption of multi-sectoral conservation measures, moving beyond fragmented, sector-specific regulation.

Building on the treaty overview, Alina Butrim (Senior Lawyer, EMVE Trading DMCC, Dubai) analysed the BBNJ Agreement as a structural shift from a freedom-based regime toward a compliance-driven framework for private actors operating on the high seas. She emphasised that the Agreement directly affects corporate risk allocation, project planning and dispute exposure.

Alina highlighted that the BBNJ Agreement closes long-standing regulatory gaps that previously enabled forum shopping under flags of convenience. By internationalising environmental impact assessments, increasing transparency and embedding the precautionary approach and ecosystem-based management, the treaty raises compliance thresholds and reallocates regulatory risk from states to private operators.

She noted that scientific uncertainty, particularly in deep-sea and open-ocean activities, can no longer be used to justify regulatory inaction and may instead support restrictions, modifications or delays of proposed projects. For sectors relying on MGRs, new notification, disclosure and benefit-sharing requirements are likely to affect research strategies, patenting practices and commercialisation timelines, while increasing exposure to non-governmental organisation scrutiny and strategic litigation.

Alina concluded that for shipping, fishing, biotechnology and marine research, early legal and environmental due diligence is no longer a procedural formality but a core element of operational strategy.

Conclusion

Closing the webinar, the panellists agreed that international environmental law is no longer confined to diplomatic negotiation. It now intersects with human rights, trade, finance, corporate governance and litigation strategy, demanding a broader, more anticipatory approach from legal advisers. For private practitioners, the message is unequivocal. Staying ahead in 2026 will require close attention not only to treaties and negotiations, but also to how international norms are translated into domestic law, corporate obligations and strategic litigation risk.

This article was prepared by the IBA Legal Policy & Research Unit