A sea change

"The sea, once it casts its spell, holds one in its net of wonder forever." Jacques Cousteau 

The treaty is built on four key pillars: 

• Marine Protected Areas (MPAs): creates the legal framework to establish MPAs in international waters, advancing the global 30x30 goal of protecting 30% of the ocean by 2030. 

• Marine Genetic Resources: Ensures that benefits from deep-sea genetic resources used in medicines, biotechnology and cosmetics are shared fairly among all nations. 

• Environmental Impact Assessments (EIAs): requires environmental assessments before approving activities that could significantly harm marine ecosystems, including deep-sea mining and other large-scale developments. 

• Capacity Building: provides financial, technical and scientific support to help developing countries strengthen ocean governance and access marine technology. 

 

 

The world's oceans have long suffered from pollution, overfishing and fragmented governance. While nations manage waters within their own borders, the high seas, covering nearly two-thirds of the ocean, have lacked meaningful international protection. Until now. 

 

Adopted under the Intergovernmental Conference on Marine Biodiversity of Areas Beyond National Jurisdiction (BBNJ), the High Seas Treaty is the first global agreement to protect biodiversity in international waters. Building on the UN Convention on the Law of the Sea, its 75 articles establish a framework for conserving marine ecosystems and ensuring the sustainable use of ocean resources for future generations. 

 

As UN Secretary-General António Guterres said at its adoption, "The ocean is the lifeblood of our planet, and today, you have pumped new life and hope to give the ocean a fighting chance." 

 

 

Millions of tonnes of plastic waste and toxic pollutants enter the ocean every year, devastating marine life and contaminating the food chain. Fish, seabirds, sea turtles, and marine mammals are among the countless species affected, while microplastics are increasingly being detected in the food and water consumed worldwide. 

 

The latest Sustainable Development Goals (SDG) Report estimates that more than 17 million metric tonnes of plastic entered the ocean in 2021, accounting for around 85% of all marine litter. Without decisive action, plastic pollution could double or even triple by 2040. UN projections also warn that by 2050 there could be more plastic than fish in the ocean by weight. 

 

The treaty responds by embedding the polluter-pays principle, requiring environmental impact assessments for activities beyond national jurisdiction, and establishing mechanisms to resolve disputes and strengthen accountability. 

 

Sustainable fishing 

 

Overfishing remains one of the greatest threats to marine biodiversity, with more than one-third of global fish stocks already exploited beyond sustainable levels. The treaty seeks to reverse this trend by strengthening international cooperation, supporting capacity building, and promoting the transfer of marine science and technology. It also encourages closer collaboration between regional seas organisations and fisheries management bodies, helping countries develop stronger regulatory frameworks and more sustainable fishing practices. 

 

 

Climate change is transforming the world's oceans at an unprecedented pace. Rising sea temperatures are intensifying storms, accelerating sea-level rise, and increasing ocean acidification, placing immense pressure on marine ecosystems and coastal communities alike. Recognising these interconnected challenges, the treaty adopts an ecosystem-based approach to ocean management that strengthens resilience, restores degraded habitats, and protects the ocean's natural carbon cycling processes. 

 

Importantly, it also recognises the rights and traditional knowledge of Indigenous peoples and local communities, safeguards the freedom of scientific research, and promotes the fair and equitable sharing of benefits arising from marine genetic resources. 

 

 

The High Seas Treaty represents far more than another international agreement. It is a crucial step towards delivering the ocean ambitions of the 2030 Agenda for Sustainable Development. It specifically supports SDG14 by helping to reduce marine pollution, combat overfishing through science-based management, and restore depleted fish stocks. 

 

Perhaps most significantly, the treaty enables the creation of large-scale marine protected areas in the high seas and the international seabed, providing a powerful new tool to conserve biodiversity and protect some of the planet's most important, yet least governed, ecosystems. Whether this landmark agreement succeeds, however, will ultimately depend on the political will, funding, and international cooperation that follows. The health of the global ocean, and the future it supports, depends on turning ambition into action. 

 

 

The UN High Seas Treaty is a landmark achievement for global ocean governance. Yet, for an island nation, the UK's domestic approach tells a less encouraging story. 

 

The Climate Change Committee's latest report, A Well Adapted UK, the fourth independent assessment of UK climate risk, contains no specific assessment of risks to marine life or fisheries, nor does it set adaptation priorities for marine ecosystems. This omission is striking given that the UK's marine territory is around six times larger than its landmass, and the health of its seas underpins biodiversity, food security, coastal economies and climate resilience. 

 

Evidence for action is growing. A recent synthesis of marine nature-based solutions examined 21 interventions, including marine protected areas, seagrass and oyster restoration, low-trophic aquaculture, and the greening of coastal infrastructure. Together, these approaches show significant potential to restore biodiversity, reverse habitat degradation, strengthen climate resilience, and deliver lasting social and economic benefits for coastal communities. 

 

But science alone is not enough. Effective ocean stewardship also requires new approaches to governance. The Scottish Association for Marine Science (SAMS) has taken a pioneering step by giving the Ocean its own seat on the Board. Represented by appointed Ocean Advocate Helen Mitcheson, the role ensures that the interests of the marine environment are formally considered in every strategic decision. Championed by SAMS Director Professor Nick Owens, this innovative model moves beyond traditional, human-centred governance by recognising the ocean as a stakeholder rather than merely a resource to be managed. Founded in 1884 during the legacy of the Scottish Enlightenment, when 18th- and early-19th-century Scotland was characterised by an outpouring of intellectual and scientific accomplishments, SAMS is the UK's oldest independent ocean research and education charity. Its governance model offers an example of how institutions can begin embedding the interests of nature into decision-making. Not as an afterthought, but as a core responsibility. 

 

The High Seas Treaty demonstrates what is possible when nations recognise that healthy oceans are fundamental to our shared future. The challenge now is to bring that same ambition closer to home. If the UK is serious about becoming a climate-resilient nation, its adaptation strategy must extend beyond the shoreline and give the marine environment the prominence it deserves. 

 

Nature, on land, at sea and in the air, cannot continue to be treated as a silent stakeholder. Whether through stronger marine adaptation policies, expanded restoration efforts, or innovative governance models that give nature a voice, the principle is the same: what sustains us deserves representation. The High Seas Treaty has shown the world what global leadership looks like. The UK now has an opportunity, and also a responsibility, to demonstrate that leadership at home.