As the United Nations Climate Conference (COP27) unfolds in Egypt, there are growing calls for countries to protect conserve and restore the ocean, which experts say is crucial for reducing further global warming and helping communities adapt to the fallout from the climate crisis; as well as keeping the ocean healthy and productive.

While the ocean and seas are often overlooked in climate negotiations, research shows they are an essential climate solution, as they store carbon that is driving climate change and provide valuable climate adaptation benefits.

Also, key to both ocean health and climate stability are wetlands which, according to the Ramsar definition, cover rivers, lakes, peatlands, reservoirs and in fact, all inland freshwater ecosystems as well as salt marshes. Land-based pollution is carried by many of these water sources to the ocean. Around one-third of all rivers in Latin America, Africa, and Asia, suffer from severe pathogenic pollution.

“The Ocean must play a critical role in helping the world counter the climate crisis,” says Leticia Carvalho, Head of the United Nations Environment Programme’s (UNEP) Marine and Freshwater Branch. “But right now, many marine environments, including coastal ecosystems, are under threat, reducing both their mitigation and adaptation potential, as well as breaking down their ability to function and provide services to humanity,” she adds. “We have no choice but to dramatically scale up action and funding to protect them.”

The ocean covers slightly more than 70 per cent of the planet’s surface. It has absorbed 90 per cent of the warming that has occurred in recent decades due to increasing greenhouse gases and 30 per cent of the carbon dioxide released into the atmosphere. But it does that at its own peril as rising temperatures and acidity make the seas inhospitable to many living organisms, disrupt ocean currents, and alter food webs on which humans, plants and animals rely.

The potential of the ocean to function as a giant sink for carbon rests on its rich biodiversity. Per hectare, mangrove forests store up to four times more carbon than most other tropical forests around the world, while seagrass sediment is one of the planet’s most efficient carbon stores. There is also emerging evidence that carbon is stored in the bodies of marine animals. Corals, mangroves and seagrass ecosystems are important breeding grounds for the huge diversity of marine animals, which keep the ocean well-functioning and productive. But the combined negative impact from people, polluted rivers and global heating is severely compromising their health.

Human activity – from overfishing to deep-sea mining to coastal infrastructure and the dumping of the equivalent of at least one garbage truck of plastic in the ocean every minute – is rapidly destroying these ocean ecosystems. Seagrass habitats, for instance, have been in decline since 1930, with 7 per cent of them disappearing each year, according to UNEP research.

Protecting the ocean requires land and sea-based action. This includes reducing the direct human impacts on the ocean, cleaning up polluted rivers, restoring wetlands and developing a circular economy where potential pollutants remain in the economy for as long as possible and at life’s end are properly disposed of.