The High Seas Treaty: Turning the Tide on the Governance of Global Commons

Chelsea Golding | Climate and Environment Fellow

Image sourced from Pexels via Pixabay.

From emissions thresholds to negotiations on who gets to mine the Moon, the management of global commons — or lack thereof — is one of the most urgent and contentious issues in international relations today. Nowhere is this challenge more evident than in the governance of the high seas. The June 2025 UN Ocean Conference (UNOC) offered renewed optimism for collective governance. Growing international support saw a new wave of ratifications for the High Seas Treaty: a landmark agreement in cooperative governance nearly twenty years in the making. As a vocal advocate of the High Seas Treaty, how Australia proceeds with ratification will be of critical importance in maintaining its credibility as a leader in ocean governance.

The High Seas as a Global Commons

For decades, destructive overexploitation of fisheries and other marine resources has made the high seas a textbook example of the ‘tragedy of the commons’. These waters —encompassing all marine space outside national jurisdiction and accounting for roughly two-thirds of the world’ s oceans – have historically been governed under the principle of ‘freedom of the seas’.  In practice, this allows all states to freely access and exploit the high seas, often in an unregulated and uncoordinated manner. This approach has severely degraded marine ecosystems, with marine species now facing extinction rates twice as high as those on land.

While the United Nations Convention on the Law of the Sea (UNCLOS) laid the groundwork for high seas governance, it simply cannot deal with the emerging threats of ecosystem collapse, as well as increasing competition for and unregulated access to valuable marine resources. Enter: The High Seas Treaty, formally known as the Biodiversity Beyond National Jurisdiction (BBNJ) Agreement.

A Turning Point for Ocean Governance

After nearly two decades of negotiation since its initial proposal, the BBNJ Agreement was adopted in June 2023 and hailed as a landmark in international environmental law. It is the first legally binding global treaty focused on conserving biodiversity in areas beyond national jurisdiction and is premised on four main pillars: 

1.         Establishing marine protected areas

2.         Mandating environmental impact assessments

3.         Enabling fair benefit-sharing of marine genetic resources

4.         Supporting technology transfer and capacity-building

At least 60 countries must ratify the treaty before it can enter into force. By the conclusion of UNOC, a wave of 19 new ratifications brought the treaty to a total of 49 ratifications, just 11 shy of the entry threshold. Australia sits among the 89 signatures to the treaty who have not yet ratified but pledged to ratify once their parliaments finalise the necessary legislation. If entered into force, the treaty would mark a historic step forward for the governance and conservation of the global ocean commons.

Why Ratification Matters Now

The High Seas Treaty entering into law would provide a blueprint for managing global commons at a time when international tensions are placing unprecedented strain on collaborative governance. Following Russia’s invasion of Ukraine, cooperation within the Arctic Council – long regarded as an exemplar of science diplomacy and cooperative management — was largely suspended by Western member states. This geopolitical fracturing has seen many climate research and Indigenous-led conservation projects paused, even as the Arctic faces warming at four times the global average.

For Australia, ratification not only shows alignment with global momentum for protecting the high seas but also advances regional interests by demonstrating support for the stability of its Pacific Island neighbours, for whom the state of the oceans is a security, environment and human rights threat. At a moment when cooperative governance is needed more than ever to address the existential threat posed by climate change, the fracturing of such institutions is not only diplomatically damaging, but fails to safeguard the safety, food security, and livelihoods of future generations.

Australia’s Response and the Path Ahead

Having signed the treaty in 2023, Australia has been an outspoken advocate for high seas protection and played an influential role in negotiations, pushing for ambitious outcomes as part of the High Ambition Coalition. Despite its strong stance, Australia was not among the 19 countries that moved to ratify the treaty during the UNOC.

However, ratification is still on Australia’s environmental agenda. Before Australia can formally ratify the treaty, it must ensure its domestic laws align with the treaty’s obligations. To do so, Parliament must pass what is known as ‘enabling legislation’-laws that amend existing domestic legislation, allowing for the treaty to be implemented. The Australian Government has stated that it plans to do so during the spring sitting of Parliament which runs from September to November. Once passed, formal ratification can proceed.

While Australia’s signature reflects strong support, and the Albanese Government has championed the agreement as a central feature of its environmental leadership, only ratification will make these commitments legally binding. Until then, Australia is unable to fully participate in the treaty’s governance and implementation.

The outcomes of the 2025 UN Ocean Conference signal a turning point in the stewardship of our global commons. The surge in ratifications of the High Seas Treaty offers a rare moment of consensus at a time of escalating geopolitical tensions, and a model for how the world can navigate increasing competition over global commons through science-based, collaborative stewardship. As the international community moves toward implementation, Australia’s next steps in finalising domestic ratification will be critical in shaping not only the future of the high seas but the credibility of Australia’s climate and ocean diplomacy.

Chelsea Golding is the Climate and Environment ellow for Young Australians in International Affairs. Chelsea is an undergraduate at the University of Queensland, pursuing a dual Bachelor of Science and Bachelor of Arts.

She has conducted policy research on offshore wind development in Australia, contributed to marine spatial planning studies, and drafted environmental legislation. Her international experience spans Malta and the Philippines, ranging from marine animal studies and coastal habitat monitoring to regulatory reviews and community-based marine policy evaluations.

As UQU’s Environmental Officer, Chelsea co-founded the Environmental Collective column and led campus sustainability initiatives. She has worked across government and research sectors and is especially interested in environmental justice and climate resilience in the Indo-Pacific.