How we can restore marine life by 2050

An international team of scientists has painstakingly mapped out positive actions that could return the planet’s marine life to its abundant glory over the next three decades.

Writing in the journal Nature, they warn that the ocean’s capacity to sustain human wellbeing – by mitigating climate change and providing food, water and oxygen – is at a critical junction.

“We are at a point where we can choose between a legacy of a resilient and vibrant ocean or an irreversibly disrupted ocean,” says lead author Carlos Duarte from the King Abdullah University of Science and Technology, Saudi Arabia.

Indeed, the United Nations Sustainable Development Goal 14 recognises the urgent need to “conserve and sustainably use the oceans, seas and marine resources for sustainable development”.

And it is achievable, the authors say. “Rebuilding marine life represents a doable grand challenge for humanity, an ethical obligation and a smart economic objective to achieve a sustainable future.”

Although human activities have had devastating impacts on marine life over the 20th century, the team drew on resilient responses of sea creatures, habitats and ecosystems to conservation efforts to demonstrate how they can be revived.

These include the spectacular recovery of humpback whales (Megaptera novaeangliae) in Australia, sea otters (Enhudra lutris) in West Canada and Baltic Sea grey seals (Halichoerus grypus) from the brink of extinction.

Other examples include large-scale habitat restoration of mangroves, reduction of organic pollutants and efforts to manage and recover fish stocks. 

Through success stories of ocean conservation and recovery trends, the researchers identify nine factors central to reviving marine life, salt marshes, mangroves, seagrasses, coral reefs, kelp, oyster reefs, fisheries, megafauna and the deep sea.  

They outline six complementary interventions called “recovery wedges” that include a suite of strategies under the themes of protecting species and spaces, harvesting prudently, restoring habitats, reducing pollution and mitigating climate change.

Recommended actions include opportunities, benefits, possible roadblocks and remedial initiatives, providing a tangible roadmap to deliver a healthy ocean. But it’s not a smorgasbord that can be picked at selectively or passively. 

The authors stress that the goals need to be adopted across the board, and that the focus should be not just conservation but actively reviving dwindling species and ecosystems to sustainably feed and support the growing human population.

Importantly, rebuilding marine life abundance can only succeed if the most ambitious goals within the Paris Agreement are met; impacts from climate change already limit the scope for rebuilding tropical corals to a partial recovery. 

Success relies heavily on a committed, global partnership of governments and societies aligned with the goal, as well as a significant financial investment. But the researchers report that the ecological, economic and social gains will be far-reaching.

The review is well-timed for this year’s G20 summit in Saudi Arabia, where nations will consider their actions to conserve biodiversity beyond 2020.

“We have a narrow window of opportunity to deliver a healthy ocean to our grandchildren’s generation, and we have the knowledge and tools to do so,” says Duarte.

“Failing to embrace this challenge – and in so doing condemning our grandchildren to a broken ocean unable to support high-quality livelihoods – is not an option.”

This time evolution of global marine protected areas compiled in the study and declared around the world shows a rapid acceleration in the 21st century. Credit: King Abdullah University of Science and Technology