LISBON, Portugal — A long-delayed UN conference on how to restore the failing health of the world’s oceans kicks off Monday in Lisbon, with thousands of policymakers, experts and advocates on the case.

Humanity needs healthy oceans. They generate 50% of the oxygen we breathe and provide essential protein and nutrients to billions of people every day.

Covering more than two-thirds of the Earth’s surface, the seven seas have also mitigated the impact of climate change on life on land.

But at a terrible price.

The absorption of about a quarter of CO2 pollution – even as emissions have increased by half over the past 60 years – has turned seawater acidic, threatening aquatic food chains and the ability to ocean to extract carbon.

And absorbing more than 90% of excess heat from global warming has spawned massive marine heatwaves that are killing precious coral reefs and expanding oxygen-deprived dead zones.

“We are only beginning to understand how devastating climate change is going to wreak on the health of the oceans,” said Charlotte de Fontaubert, global head of blue economy at the World Bank.

According to the United Nations Environment Program (UNEP), an endless torrent of pollution, including the equivalent of a garbage truck full of plastic every minute, is making matters worse.

On current trends, annual plastic waste will nearly triple to one billion tonnes by 2060, according to a recent OECD report.

Wild fish stocks

Microplastics, found in Arctic ice and fish in the deepest trenches of the ocean, are estimated to kill more than one million seabirds and more than 100,000 marine mammals each year.

The solutions on the table range from recycling to global plastic production caps.

Global fisheries will also be in the spotlight at the five-day UN Ocean Conference, originally scheduled for April 2020 and co-hosted by Portugal and Kenya.

“At least a third of wild fish stocks are overexploited and less than 10% of the ocean is protected,” Kathryn Matthews, scientific manager of the American NGO Oceana, told AFP.

“Destructive and illegal fishing vessels operate with impunity in many coastal waters and on the high seas.”

One of the culprits is nearly $35 billion in subsidies. Small steps taken last week by the World Trade Organization (WTO) to cut donations to industry will make little difference, experts said.

The conference will also see push for a moratorium on deep-sea mining of rare metals needed to build a burgeoning battery of electric vehicles.

Scientists say poorly understood seabed ecosystems are fragile and could take decades or more to heal once disturbed.

Another major focus is “blue food”, a new watchword to ensure that marine harvests from all sources are sustainable and socially responsible.

Protected areas

Increasing yields from aquaculture – from salmon and tuna to shellfish and seaweed – are on track to outpace wild marine harvests that have been declining since the 1990s, each producing around 100 million tonnes a year.

If properly managed, “wild ocean fish can provide a climate-smart source of micronutrient protein that can feed a billion people with a healthy seafood meal every day, forever,” he said. Matthews.

The Lisbon meeting will see ministers and even a few heads of state, including French President Emmanuel Macron, but is not a formal negotiating session.

But participants will push for a strong ocean agenda at two critical summits later this year: the UN COP27 climate talks in November, hosted by Egypt, followed by the the long-delayed COP15, recently moved from China to Montreal.

The oceans are already at the heart of a proposed biodiversity treaty tasked with stopping what many scientists fear will be the first “mass extinction” in 65 million years.

Nearly 100 nations support a fundamental provision that would designate 30% of the world’s land and oceans as protected areas.

For climate change, the focus will be on carbon sequestration: increasing the ocean’s ability to absorb CO2, whether by enhancing natural sinks such as mangroves or through geo-engineering programs.

At the same time, scientists warn, a drastic reduction in greenhouse gases is needed to restore the health of the oceans.