Environmental Dispute Resolution

The PCA continues to play a critical role in the resolution of international environmental disputes between States, State entities, intergovernmental organizations, and private parties.

To that end, the PCA has been included as the forum for dispute resolution in a range of multilateral environmental treaties and other environmental agreements, addressing the conservation of species and habitats, the consequences of transboundary pollution and other threats to the environment, as well as the functioning of international environmental organisations.

As the nature of the environmental challenges facing the international community continues to evolve, the PCA stands ready to assist with the resolution of disputes arising from these challenges.

Inter-State environmental dispute settlement

A number of the most significant environmental disputes between States have been resolved by way of arbitration under the aegis of the PCA.  These disputes have concerned matters as diverse as the processing of nuclear fuel, the protection of coral reefs and other marine features, hydro-electric power development, and the detention of environmental protestors.

The PCA has also administered other forms of dispute settlement for inter-State disputes with an environmental dimension, including three Review Panel procedures under the SPRFMO Convention, with regard to the allocation of shares of total allowable catch in certain South Pacific fisheries (PCA Case No. 2013-14, Review Panel established under the Convention on the Conservation and Management of High Seas Fishery Resources in the South Pacific Ocean (Russian Federation Objection); PCA Case No. 2018-13, Review Panel established under the Convention on the Conservation and Management of High Seas Fishery Resources in the South Pacific Ocean (Ecuador Objection); PCA Case No. 2023-33, Review Panel established under the Convention on the Conservation and Management of High Seas Fishery Resources in the South Pacific Ocean (Russian Federation Objection)). These procedures have involved the participation of a large number of States (alongside the SPRFMO Commission itself), with oral and written submissions in multiple languages, and have required the resolution of the dispute on a highly expedited basis (within 45 days of the establishment of the Panel).

Inter-State environmental disputes administered by the PCA have arisen under a variety of legal instruments, including multilateral treaties such as the 1992 OSPAR Convention, the 1982 UN Convention on the Law of the Sea, the 1960 Indus Waters Treaty, and the 1976 Rhine Chlorides Convention. PCA-administered interstate environmental disputes have also arisen under bilateral treaties and ad hoc arbitration agreements. Additionally, the PCA has been included as the appointing authority and/or the forum for the arbitration of disputes arising out of a number of multilateral environmental treaties (listed below). The PCA is also among the dispute settlement options recommended in the Draft International Covenant on Environment and Development, a model agreement developed by non-governmental organizations with the aim of facilitating treaty negotiations in the environmental sector.

Mixed environmental disputes

The PCA administers disputes between States and non-State actors arising under a range of bilateral and multilateral investment treaties, contracts, and other instruments. Several of these disputes concern legal issues relating to domestic environmental regulatory frameworks as well as host State obligations under international environmental law. For example, the PCA has administered a number of disputes relating to the Kyoto Protocol’s Clean Development Mechanism, and has also been referenced in a number of other notable instruments arising out of multilateral environmental frameworks:

• The Compact: A Contractual Mechanism for Response in the Event of Damage to Biological Diversity Caused by the Release of a Living Modified Organism, a private sector initiative concerning liability issues arising out of the 1992 Convention on Biological Diversity, provides for binding arbitration between a State and a signatory company.
• The Gold Standard Foundation, a body that provides a certification scheme for premium quality carbon credits generated by qualifying projects under the Kyoto Protocol’s Clean Development Mechanism and other carbon-trading schemes, has included an adapted version of the PCA’s optional rules in their process for appeals against certification decisions.
• The Green Climate Fund (GCF), a new multilateral fund designed to help developing countries limit or reduce their greenhouse gas emissions and adapt to the unavoidable impacts of climate change, incorporates the PCA Arbitration Rules in a number of GCF-related instruments.

Specialized environmental rules for arbitration and conciliation

Disputes with a conservation, natural resources, or environmental protection component often have particular characteristics that may need to be accommodated in the applicable procedures.  For example:

• Parties may choose to have environmental disputes resolved by decision-makers with specific scientific or technical expertise, in addition to, or in lieu of, legal expertise;
• the way in which evidence is gathered and presented may also need to be adapted (for example, through the use of site visits, or tribunal-appointed experts); and
• the public interest in the subject matter of the dispute could warrant the development of special procedures on the transparency of the proceedings, and/or submissions from third parties.

Building on its experience administering environmental disputes, the PCA developed specialised arbitration and conciliation rules to reflect the particular characteristics of environmental disputes.  In 2001, the PCA Optional Rules for Arbitration of Disputes Relating to the Environment and/or Natural Resources (“Environmental Rules”) were adopted. These Rules were drafted by a working group and committee of experts in environmental law and arbitration in order to address the principal lacunae in environmental dispute resolution. The PCA Optional Rules for Conciliation of Disputes Relating to the Environment and/or Natural Resources were adopted in 2002. The PCA’s Environmental Rules for arbitration and conciliation provide the most comprehensive set of environmentally tailored dispute resolution procedural rules presently available. The PCA’s Environmental Rules are referred to in a treaties and contracts, such as the 2003 Protocol on Civil Liability and Compensation for Damage Caused by the Transboundary Effects of Industrial Accidents on Transboundary Waters and the Model Emissions Reduction Purchase Agreements developed by the International Emissions Trading Association.

In turn, States, State entities, intergovernmental organizations, and private parties have incorporated these rules into their bilateral and multilateral treaties, contracts, and other agreements.

The Environmental Rules provide for the establishment of a specialized list of arbitrators considered to have expertise in this area. The Environmental Rules also provide for the establishment of a list of scientific and technical experts who may be appointed as expert witnesses pursuant to these Rules.  Parties to a dispute are free to choose arbitrators, conciliators and expert witnesses from these Panels. However, the choice of arbitrators, conciliators or experts is not limited to the PCA Panels.

The PCA is available to give advice and assistance to States, international organizations and private parties involved in the design and administration of new, specialized environmental dispute settlement procedures.

Shaping the future of environmental dispute settlement

Beyond the administration of specific environmental disputes, the PCA actively contributes to the development of international environmental law by sharing its expertise in the context of international environmental negotiations, and by building the capacity of practitioners from States, intergovernmental organizations, and civil society.

In the past, the PCA has collaborated with the UN Environment Programme to convene a joint Advisory Group to consider developments in the field of environmental dispute resolution. The PCA has participated in the negotiations on developing liability and redress mechanisms under the UN Convention on Biological Diversity and the Intergovernmental Committee for the Biosafety Protocol. The PCA has also contributed to a report of the Secretariat of the UN Convention to Combat Desertification on the design of treaty-based environmental arbitration and conciliation procedures.

For example, in 2025, PCA representatives participated in the Conference of the Parties to the UNFCCC (COP31) held in Belém, Brazil, engaging with State negotiators on the future of climate change-related dispute settlement.  PCA representatives also briefed officials from the European Commission (DG MARE) on the unique procedural issues raised by environmental disputes, and addressed State officials and practitioners from across the Pacific on climate change-related dispute settlement as part of the Hague Academy of International Law’s External Programme in Port Vila, Vanuatu.