World Oceans Day is a reminder of the perils facing underwater realms

Even if you don’t live beside an ocean, chances are your existence is wedded to the sea.

Oceans provide food for billions of people. They regulate the climate; without their cooling effects, global temperatures could rise to an inhospitable 100°C. And oceans churn out more than half the planet’s oxygen, with one type of marine bacteria, Prochlorococcus, producing more of the life-sustaining gas than all tropical rainforests combined.

But human activity has taken a toll on the oceans. According to Becoming #GenerationRestoration, a recent report by the United Nations Environment Programme (UNEP) and the Food and Agriculture Organization, “the massive economic growth of recent decades has come at the cost of ecological health.”

With 90 per cent of big fish populations depleted, and half of coral reefs destroyed, humans are taking more from the ocean than can be replenished – with consequences that are increasingly difficult to ignore.

“The fates of billions of people are tied to the world’s oceans,” said Susan Gardner, Director of UNEP’s Ecosystems Division. “In the coming years, the planet needs to come together to relieve the pressure on our oceans and undo the damage that has been done.”

That’s a message experts are urging politicians, business leaders and everyday people to take to heart as the planet celebrates World Oceans Day on 8 June.

Mangroves are being planted at a heavily eroded beach in Telescope, Grenada.
Mangroves are being planted at a heavily eroded beach in Telescope, Grenada. Photo: Kadir van Lohuizen / NOOR
Economic impact

World Oceans Day comes at what experts call a critical time. UNEP studies have found that rising water temperatures and acidification are affecting the productivity and distribution of marine fish stocks. This, along with overfishing, has put the livelihoods of 60 million fishers at risk. The impact of marine degradation is also being felt at national levels. In Australia, for example, the loss of corals now threatens the 64,000 jobs and 6.4 billion Australian dollars that the Great Barrier Reef brings to the national economy. On a global scale, ocean acidification could result in losses of $1 trillion every year by 2100.

Climate change

Over the last 50 years, marine “dead zones” have expanded by 4.5 million kilometres – roughly the size of the European Union – as a result of oxygen depletion. Unless greenhouse gas emissions are drastically reduced, bleaching and acidification is expected to cause the disappearance of the world’s coral reefs by the end of the century.

Nonetheless, ocean temperatures continue to increase, with detrimental effects. Last year, more than 80 per cent of the world’s oceans experienced marine heatwaves, stimulating extreme weather events experienced in every region of the world.

At the same time, coastal development and construction have contributed to the loss of mangroves, seagrass and coral reefs, as well as their ability to slow floodwater release and reduce wave heights. A UNEP report from 2017 found that, with sea levels rising and 40 per cent of people living within 100 km of coastlines, this represents an invaluable loss of natural protection.

Oceans are the lungs of our planet. Human life depends on them.

Restoring oceans, restoring life

To protect and preserve the ocean and all it sustains requires an understanding of the ocean and putting an end to decades of exploitation, say experts. Under the theme, Life and Livelihoods, World Oceans Day aims to jumpstart that process, as does the UN Decade of Ocean Science for Sustainable Development (2021 – 2030). This global push, which begins this year, is designed to bolster marine science and leverage it to sustainably manage the Earth’s underwater resources. That dovetails with Sustainable Development Goal 14 to conserve and sustainably use the oceans, seas and marine resources by 2030.