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World Oceans Day – June 8, 2023 - Turning the Tide


-Image courtesy of the UN World Oceans Day Media Toolkit

It was also World Ocean Day this week and the oceans have also enjoyed a major victory this year with the passage of the High Seas Treaty in which 200 countries have committed to protecting 30% of our land, waters and oceans by 2030.

The ocean covers 70% of the earth's surface and is home to 80% of the world's biodiversity. Unfortunately, 10% of its 2 million known species are already at risk of extinction and 90% of it's large fish are already depleted, so this agreement is long overdue, especially when other risks to our oceans are taken into account.

The Agreement itself is only a beginning. At least 60 countries must now ratify it and pass legislation within their own countries for it to become binding. The previous agreement about the high seas - the UN Convention on the Law of the Sea agreed in 1982, was all about ensuring the freedom of shipping to go where it pleased beyond each country's EEZ - the 2000 nautical mile economic zones beyond their borders. The new agreement defines shipping lanes, where fishing and exploration and mining can occur and also seeks to limit ocean dumping of rubbish and fishing gear. The ocean will no longer be the Wild West where anything goes. 

While this is cause for celebration, there are also limitations. For example, who will monitor and protect these regions? At present there is no overarching authority, there are no uniform standards and not all countries have the same capacity for monitoring and enforcement. Nor has it been decided how the spoils of the ocean should be shared among competing countries. We don’t even know what’s there and in some cases the little that is known is not shared or is inadequate to establish baselines. 

Known threats

Many also argue that the Agreement doesn’t go far enough, given that the ocean now faces a number of new threats. We saw in a previous post how widespread ocean plastic pollution is. We are also long familiar with the effects of uncontrolled fishing, overfishing and destructive fishing practices such as bottom trawling and shark finning – leaving helpless sharks unable to swim or defend themselves, and all of which have a devastating impact on the species we are trying to save.

Oil pollution, spillage or dumping of toxic waste, including radioactive waste are also of concern, as is agricultural run-off, rich with manure and fertilisers, which contribute to algal blooms, some of which can be toxic to humans and other species including marine life. While Australia is cracking down on emissions and garbage coming from ships, dumping of sewerage, dredging, coastal works and tourist activities such as boating create dead zones in places which were once nurseries for fish. The same goes for clearing of mangroves and filling in of swamps and marshlands which are needed to filter water on its way to the sea.

The Impact of Climate Change

Our coral reefs – the other biodiversity rich nurseries for marine species, are also in trouble with 50% of them damaged or destroyed. Bleaching events are becoming more frequent and more permanent due to climate change. Though some species have recovered, it is often at the expense of rarer and more beautiful corals and the sea life which depends on them. Warmer waters also allow predators and diseases to move further south or north into areas which were previously protected by the cold.

As our oceans continue to warm, they become more acidic making it more difficult for shellfish to form shells and corals to flourish. In the short term this will affect anyone who relies on shellfish for their diet or livelihood. Sediment cores tell us that oceans have become 30% more acidic since 1750 because they have absorbed 50% of the C02 emissions produced since the Industrial Revolution began. It also reduces the amount of oxygen available to marine species. The problem of deoxgenation is far more serious than previously thought, at least as serious as warming and acidificaction. See the Yale 360° Report on this here or the consequences here. The fossil record tells us that a similar deoxygenation event occurred about 56 million years ago and resulted in major extinctions. The oceans incidentally also produce around half the oxygen we breathe on land. 

Other Threats

Newer threats include deep sea mining* and exploitation of biological materials found on the seabed. There is also the weakening of the ocean circulation which brings warm salty waters via the Gulf Stream to the North Atlantic (The Atlantic Meridional Overturning Circulation (AMOC) and drives not only the global circulation of seawater but also the wind and weather. The weakening is thought to be partially due directly to warming, but also through oceans becoming less saline - due to melting ice sheets, glaciers and polar ice caps, a major factor in the process.

Will the Treaty halt all these threats? This is unlikely. However, like the Plastics Treaty it’s a start and highlights both the importance and the fragility of the ocean environment and the need to protect it. It is after all, regarded as the cradle of all life on earth and currently sustains some 2 billion people. The battle for the oceans is not won. We must all urge our leaders to act as quickly and comprehensively as possible, including reducing emissions, if we really want to Turn the Tide. 

* See this recent article on deep sea mining about why the economic arguments aren't very sound either, given that newer EV batteries use common materials such as iron and sulphur instead of nickel and cobalt.