UN Special Rapporteur on the Human Right to a Clean, Healthy, and Sustainable Environment Intervenes in Proceedings in an Australian First

Background

On May 25, 2026, Astrid Puentes Riaño, the UN Special Rapporteur on the Human Right to a Clean, Healthy, and Sustainable Environment ("UN Special Rapporteur"), successfully applied to intervene in three separate Federal Court proceedings in Australia ("the Proceedings"), case numbers: VID1400/2025, VID1356/2025 and VID1357/2025. For the purposes of this article, the Proceedings will be described collectively, noting that:

• All of the Proceedings are against the federal Minister for the Environment ("the Minister").
• All of the Proceedings were brought by two environmental groups, the Australian Conservation Foundation ("ACF") and Friends of Australian Rock Art ("FARA").
• All of the Proceedings concern the approval under the Environment Protection and Biodiversity Conservation Act 1999 ("EPBC Act") to extend the life of Woodside's North West Shelf gas project ("the Project") until 2070.
• The EPBC Act is Australia's federal legislation designed to protect matters of national environmental significance.
• The UN Special Rapporteur is an intervenor in all of the Proceedings.

This is the first time the UN Special Rapporteur has intervened in proceedings in Australia.

Basis of the UN Special Rapporteur's Intervention

The UN Special Rapporteur is an intervenor in the Proceedings as an amicus curiae, seeking to be heard on the international law context of the EPBC Act as it relates to the Proceedings.

In support of this application, the UN Special Rapporteur submitted that:

• United Nations bodies have previously appeared in other proceedings as amicus curiae;
• Previous decisions in the Federal Court have acknowledged that "the clearest example of an amicus curiae is an 'official body' or 'entit[y] acting in the public interest.'" Submissions made by the UN Special Rapporteur and dated April 27, 2026, see: page 2. These would be the circumstances in which the UN Special Rapporteur would be acting.
• The UN Special Rapporteur has special expertise and experience in respect of environmental laws, including those relating to climate change and environmental impact assessments.
• "The text and context of the EPBC Act confirms the relevance of international law obligations." Ibid. see: page 4.
• International law obligations are not included in the submissions of any of the parties to the Proceedings, meaning that the Court would benefit from the submissions of the UN Special Rapporteur.

The Court agreed that the UN Special Rapporteur should be appointed amicus curiae and be permitted to make submissions.

UN Special Rapporteur's Submissions

On June 2, 2026, the UN Special Rapporteur made Submissions in the Proceedings which described the basis on which they intervened in the Proceedings and their position in relation to the key issues in the Proceedings. This position is informed by their experience and understanding of international law and broader commentary provided by their legal representatives as to how international law informs the EPBC Act and Australia's obligations in relation to international law.

In short, the UN Special Rapporteur's submissions related to the following:

• The UN Special Rapporteur considered that their role in the Proceedings, at a high level, is to identify the international law obligations that inform the construction of the relevant statutory terms in the EPBC Act.
• Two specific legal issues in the Proceedings: (i) the correct interpretation of the phrase "substantial cause" in s 527E(1)(b) of the EPBC Act, which determines whether the physical effects of climate change constitute an "impact" on the Project; and (ii) the content of the obligation in s 137A of the EPBC Act not to act in a way which is contrary to National Heritage Management Principles ("the Principles")―"specifically, what the obligation to protect and transmit heritage values 'to all generations' requires where climate change poses an acknowledged, serious, and irreversible threat to those values over a 45-year approval period" (page 1 of the Submissions).

The UN Special Rapporteur's position on each of these issues is discussed below.

"Substantial Cause" Under s 527E(1)(b) of the EPBC Act

The UN Special Rapporteur considered that the Minister did not properly construe the term "substantial cause," because his reasoning was purely "arithmetic" in addressing the impact of climate change attributable to the Project. That is, the UN Special Rapporteur argued that, consistent with international law, "the better interpretation of 'substantial cause' is that it cannot be answered in a purely arithmetic way. An action may be a substantial cause of an event or circumstances even if its contribution is numerically small" (page 16 of the Submissions).

That is, the Minister should not have limited his consideration to an arithmetic assessment, noting that even a small percentage contribution to global emissions could be said to have a "substantial" impact on the progress of climate change.

Application of National Heritage Management Principles

While it was acknowledged that the National Heritage Management Principles were not created in response to an international document, the UN Special Rapporteur considered that they were still able to provide comments on the basis that the contents of the National Heritage Management Principles parallel principles found in international law.

The UN Special Rapporteur raised concerns that the conditions imposed on the extension of the Project "cannot respond to unknown future emissions" and the Court must consider whether this is consistent with "an obligation to protect and transmit the heritage values of the Dampier Archipelago to all generations".  

Potential Impact on Business

The Proceedings demonstrate a heightened risk that project approvals will be subject to challenges brought by climate activists and sophisticated environmental organizations, including the UN Special Rapporteur.

The Proceedings also create legal precedent that may lead to increased scrutiny of prospective approvals, and the increased cost burden that comes with such scrutiny.

The UN Special Rapporteur's intervention, which is the first of its kind in Australia, signals the potential for further interventions by UN Special Rapporteurs in future proposals requiring approval under the EPBC Act, particularly in respect of contentious proposals such as mining and gas projects.