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Photo by Shane Stagner / Unsplash

Today is the final day of the UN Conference on the Ocean, which has seen hundreds of leaders, activists and scientists descend on the Portuguese capital, Lisbon, to work on solutions to restore the ocean’s health and protect its future. A large part of this will be to scale up Ocean Action Based on Science and Innovation for the Implementation of Goal 14 of the Sustainable Development Goals.

The ocean is the planet’s largest biosphere, covering 70 per cent of the Earth’s surface, and home to up to 80 per cent of all life in the world. It nurtures unimaginable biodiversity, produces food, and provides jobs, mineral and energy resources needed for life on the planet to survive and thrive.

The world’s oceans are of course vast, and the threats they face are myriad and complex: from overfishing and dumping of toxic waste to rising sea levels, plastic waste and increased acidification, The ocean is also is a major part of the planet’s climate system, why it is vital that we protect it so it can continue to play the incredibly important role it does regulating our climate.

Andrew Hudson is the head of Head of the United Nations Development Programme’s Water and Ocean Governance Programme, and a man deeply familiar with both the ocean’s importance to humanity and the challenges it is currently facing.

He mentions four big issues around the ocean: sea level rises, ocean acidification, ocean deoxygenation, and ocean warming.

Hudson uses global warming to illustrate the importance of the ocean to the survival of humankind. “93 per cent of the extra heat caused by climate change is absorbed by the ocean and 7 per cent by the atmosphere. [Consider then] that the atmosphere has warmed about 1 degree so far. If that 7 per cent caused one degree of warming, and the other 93 per cent is in the ocean (which has also warmed up about one degree), imagine if we didn’t have the ocean? That other 93 per cent would be in the atmosphere which would mean a global warming of 13 degrees, and we would already be cooked.”

Yet, according to Hudson, acidification of the ocean is the biggest issue it currently faces.

“The pH level of the ocean – its acidity level – has been remarkably stable for tens of millions of years, having a pH level of about 8.2, or 8.3. In the past hundred years of industrialization, we have knocked that down by 30 per cent; so, the ocean is 30 per cent more acidic than it was 50 or 100 years ago,” Hudson says.

“The ocean has not acidified this fast or close to this fast for 55 million years.” And, 55 million years ago was not a great time to be on the planet. “That event was associated with a huge mass extinction on Earth, particularly of marine species. This is an indicator of how important and how profound this change is to the ocean.”

This rising acidification affects the ocean in a number of ways. Firstly, shell-forming animals such as corals, oysters, crabs and urchins are unable to form shells when the water is too acidified.

Scientists have already seen evidence of this in Antarctica’s Southern Ocean, where due to the water being colder, the ocean’s acidity level is rising faster – due to the C02 dissolving faster – than elsewhere in the world. “We see that Pteropods (tiny planktonic sea snails) and Zooplankton ­– which are a key part of the food chain are already experiencing difficulty forming their shells ­– and have deformed shells in some instances, which really is a canary in the coalmine. Ocean acidification an existential threat to some very important organisms in the ocean.”

While these organisms may be small, they are an important part of the marine ecosystem. “If certain species go extinct that would ripple up and down the food chain. So, for example, zooplankton feeds on phytoplankton, which are fed on by small fish and larger organisms, so any extinction would lead to complete restructuring of some marine ecosystems, ultimately simplifying and making the ecosystem less complex andlessresilient.”

Despite the doom and gloom around the ocean, Hudson is optimistic that change is possible, and indeed is happening right now. “Every positive step towards the Paris Agreement has a corresponding effect on the ocean: it reduces the rate of ocean acidification, it reduces the rate of ocean warming and it reduces the rate of ocean deoxygenation.

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