A landmark agreement to protect the world’s oceans has been reached by nations after almost 20 years of talks.

The United Nations High Seas Treaty will place 30% of the world's oceans into protected areas and provide more money for marine conservation. For the first time, it will also require the assessment of impact of economic activities, such as mining, on high seas biodiversity.

The legal framework will apply to the areas of ocean outside national boundaries, known as the high seas, which is the largest habitat on earth and home to millions of species, including turtles, great white sharks and blue whales.

However, the habitat is under mounting pressure from pollution - including noise - overexploitation, climate change and decreasing biodiversity. With currently just over 1% of the high seas protected, the new treaty will provide a pathway to greater protection of these waters.

The agreement was reached on 4 March 2023 after 38 hours of talks led by Ambassador Rena Lee, of Singapore. To a standing ovation at UN headquarters in New York, Lee announced, “Ladies and gentleman, the ship has reached the shore.”

UN Secretary-General António Guterres congratulated member countries for finalising the text, calling it a “breakthrough” after nearly two decades of talks.

He said: “This action is a victory for multilateralism and for global efforts to counter the destructive trends facing ocean health, now and for generations to come.

“It is 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.”

The High Seas Alliance, a partnership of more than 40 organisations working to establish protected areas and strengthen governance, welcomed the news. Director Rebecca Hubbard said, “Following a two-week long rollercoaster ride of negotiations and superhero efforts in the last 48 hours, governments reached agreement on key issues that will advance protection and better management of marine biodiversity in the high seas.

“It’s been a very long journey to get to a treaty. We will be looking to the 52 states that make up the high ambition coalition to lead the charge to adopt, ratify and identify important high seas areas to protect.”

Reacting on Twitter, president of the European Commission Ursula von der Leyen, said, “The ocean is food, energy, life. It has given humanity so much - it’s time to give back. I welcome the agreement on the High Seas; a treaty that will protect the ocean beyond national jurisdiction. We made it!”