An historic treaty to protect the ocean has been agreed at the United Nations, nearly two decades after talks started to deliver a legally binding deal to protect biodiversity in waters that sit outside national boundaries.

Hailed as the High Seas Treaty, the new deal commits the vast majority of the world's governments to boosting funding for marine conservation and creating a network of marine protected areas in international waters that would enable countries to follow through with their promise, made at the COP15 UN Biodiversity Conference in December, to protect 30 percent of land and sea by 2030.

Wide-ranging new rules on how to fairly share ocean resources have also been agreed through the new treaty.

Ambassador Rena Lee of Singapore, president of the talks, announced the agreement of the text late Saturday night, bringing a grueling final negotiating session that lasted more than 36 hours to an end. "Ladies and gentlemen, the ship has reached the shore," she said.

The ocean is the world's largest carbon sink and contains 95 percent of the planet's biosphere. But a loose patchwork of weakly enforced rules governing international waters have meant most of the planet's oceans are highly susceptible to exploitation whether through over-fishing, acidification and pollution, or emerging threats such as deep water mining.

Only 1.2 percent of international waters have protected status, with just 0.8 percent identified as highly protected, according to the international Union for Conservation of Nature.

The new treaty aims to remedy the low levels of protection by providing countries with new legal tools to establish and manage marine protected areas in international waters. Countries have also pledged to ensure all activities that have potential to affect ocean life are subject to an environmental impact assessment to evaluate the potential damage that could result and make such information public.

Green groups welcomed the new obligation, noting that environmental impact assessments were especially important when it comes to emerging activities such as deep seabed mining and deep-sea carbon capture and storage, where there is huge uncertainty over how environmental impacts could play out.

United Nations Secretary General Antonio Guterres said the deal, finalized after two weeks of marathon negotiations between country teams at the UN's headquarters in New York, marked a "victory for multilateralism."

Guterres said the treaty was crucial for addressing the triple planetary crisis of climate change, biodiversity loss and pollution. "It is also vital for achieving ocean-related goals and targets of the 2030 Agenda for Sustainable Development, and the Kunming-Montreal Global Biodiversity Framework," he said, referring to the so-called 30x30 pledge made at last year's COP15 Summit to protect a third of the world's land and sea for biodiversity by 2030.

Observers had warned countries would fail to meet the 30x30 target agreed in Montreal in December without new legal powers to create a network of marine protected areas on the high seas given roughly two-thirds of the ocean lies outside national jurisdictions.

The High Seas Treaty also calls for the establishment of a number of new bodies and working groups charged with governance and compliance of international marine protected area management and environmental impact assessments, and proposes an initial upf