The sea covers 71% of the world’s surface. Two out of every five people live near to or depend on the sea for their livelihood. If the sea were a country, it would be the sixth biggest economy. Ocean-based activities, including offshore energy, shipping, tourism and fishing, account for more than 5% of global GDP, while the World Bank claims that future economic growth will be led by “blue growth”. Yet the “blue economy” receives little attention from politicians or economists. A waffling section in the first draft of the Cop27 agreement in Egypt, mentioning informal meetings, quickly disappeared. Another United Nations circus is taking place Montreal this week, known as Cop15, which seeks to protect biodiversity. The danger is that ministers and diplomats will again be diverted from the economic causes of the crisis and let capital and finance continue to plunder nature. The sea, seabed and seashore have become the largest sphere of privatisation. In 1982 the UN convention on the law of the sea (Unclos) ushered in the biggest enclosure in history, converting a third of the world’s ocean area into state property by granting coastal countries 200 nautical miles from their shores as exclusive economic zones (EEZs). Colonial powers with far-flung island territories did best: France and the US gained more than 11m sq km of sea area each, while the UK gained 6.8m sq km, 27 times its land area. State ownership allows governments to hand exploitation of ocean resources to private companies. The UK and other countries have sold or granted private property rights in the sea with abandon. The result has been rampant profiteering that has ravaged the ocean environment, depleting fish populations, pumping sewage, chemicals and plastics into the sea, and destroying wetlands, mangroves and other coastal ecosystems for aquaculture and tourism development. So what should Cop15 do? It aims to give teeth to the convention on biological diversity adopted in 1992 that was ratified by 196 countries, with the glaring exception of the US. China, which has the presidency this year, has a poor record on biodiversity. It is reckoned to be the world’s worst offender when it comes to overfishing and illegal fishing. The country is also responsible for consuming half the 40-50bn tonnes of sand and gravel that is excavated each year from marine, coastal and freshwater ecosystems, mostly used to make cement. This has led to a global shortage of sand, coastline and riverbank erosion and widespread habitat destruction. In this context, negotiators and civil society organisations should focus on measures that would stop further damage and improve ecosystems. They should seek progress on the following proposals. Countries should commit to scrapping the subsidies given to industrial fisheries, £22bn of which contributes to overfishing and illegal fishing, devastating fish populations and marine food chains. They should also end subsidies to offshore oil and gas, which pose a direct pollution threat as well as fuelling the climate crisis. They should emphasise, too, securing the sea’s marine protected zones through adequate policing, proper penalties and a ban on bottom trawling – the practice of dragging huge nets along the sea floor that scoop up everything and damage the seabed. Monitoring fisheries is vital everywhere, and large fishing vessels should be required to carry independent monitoring teams. Regional fisheries management organisations (RFMOs), which are supposed to regulate major fishing areas and species, should ban representatives of companies and their financial backers from their decision-making bodies. At present, they dominate most RFMOs, inhibiting measures to curb overfishing and destructive practices. And fishing access agreements and joint ventures between countries with long-distance fisheries and developing countries should be made transparent, with deterrent penalties for rule-breaking. Noise pollution is an acknowledged threat to ocean ecosystems, disrupting the breeding patterns and migration routes of marine mammals. Ocean noise levels have doubled every decade since the 1950s, the main culprits being shipping and airguns used in seismic mapping for offshore oil and gas exploration. Governments should commit to reducing ocean noise, including curbs on ship engines. Cop15 should also back a moratorium on proposed deep-sea mining in national and international waters, which could have a catastrophic environmental impact. Hundreds of scientists and policymakers have already called for such a ban. Massive machines would scour the ocean bed to pick up nodules containing cobalt, lithium and other minerals as well as rare earths, used to manufacture electronic devices, electric vehicles and wind turbines, among other things. Apart from destroying everything in their path, they create sediment plumes that can suffocate coral reefs and other organisms hundreds of miles from mining sites. And mining damages the ocean’s ability to act as a carbon sink, accelerating global warming. As of now, only exploration for minerals is permitted by the International Seabed Authority (ISA), which was set up in 1994 to regulate deep-sea mining in international waters. But without concerted international opposition, large-scale mining could start as early as next July, after the Pacific island of Nauru triggered an obscure rule in Unclos requiring the ISA to devise regulations within two years or allow commercial mining to go ahead. Either way, the starting gun on mining has been fired. Finally, governments of rich countries should commit to doubling the proportion of official development assistance given to ocean protection from its current 1.6%. What should Britain offer? It should commit to turning marine conservation zones from barely protected “paper parks” to properly protected areas, and ban bottom trawling. It should make breaking fishing quota rules a criminal offence, not a civil one, with the added penalty of loss of quota rights. It should halt further auctions of seabed exploitation rights to multinationals by the crown estate, and it should reverse the budget and staff cuts to the Marine Management Organisation. And, besides supporting an international moratorium on deep-sea mining, it should should provide greater transparency on mining exploration licences it has given. None of these proposals would be vastly expensive. All would have beneficial effects. Sadly, many will be opposed by corporate and financial lobbyists. That is why they should not be at Cop15 at all. But they will be, in droves. Guy Standing is the author of The Blue Commons: Rescuing the Economy of the Sea