Yellow fin tuna stacked up in a shipping container after bring off-loaded from a fishing ship in Avarua on Rarotonga.

Europe’s fisheries are catching yellowfin tuna at unsustainable levels, scientists say.Credit: Marty Melville/AFP/Getty

It is a heart-breaking litany. As the world warms, its oceans are acidifying — they have become 30% more acidic during the industrial era. The area covered by low-oxygen marine ‘dead zones’, which are almost devoid of life, has more than quadrupled1 since 1960. By 2025, the amount of plastic in the seas is expected to total 150 million tonnes2. Even now, only 3% of the ocean is strongly protected by marine reserves.

None of the 17 United Nations Sustainable Development Goals (SDGs) is on track to be achieved by 2030, as Nature has been reporting in this series of editorials. But progress on a few, including the 14th goal — to conserve and sustainably use the oceans — has actually been going backwards since the 2015 UN summit at which the SDGs were agreed.

SDG 14 comprises ten targets and pledges intended to address acidification, pollution, overfishing, biodiversity loss and other ocean ills. Three are on track, and two others are progressing, albeit too slowly to be achieved by the deadline. The remaining five have either stagnated or regressed. This failure is not for want of talking or pledging. In 2020, under the auspices of a High Level Panel for a Sustainable Ocean Economy (the Ocean Panel), co-chaired by Norway and Palau, 14 coastal states committed to 100% sustainable management of their waters by 2025. By the end of 2022, 17 countries, accounting for more than 40% of the world’s coastal zones, were covered by this pact.

In February 2022, meanwhile, France hosted representatives of more than 100 countries at a historic ocean summit in Brest. A number of attendees vowed to join a plan to protect 30% of the ocean by 2030, to adopt new laws to safeguard marine life in waters beyond national ownership, and to end illegal, unreported and unregulated fishing, a term that covers a gamut of unsustainable practices that cost the global economy up to US$50 billion a year.

It’s not a lack of knowledge that’s stopping words being translated into actions. In 2018, the Ocean Panel commissioned a two-year review of available intelligence on ocean threats and opportunities, from some 250 experts around the world, closing many existing gaps. That’s not to say there isn’t room for improvement — there’s a need for better regional data on fish biomass, for instance, which could help efforts to determine where and how to protect stocks.

But the one gap science alone cannot fill is a lack of leadership, something that is most evident in the disturbing misalignment of promises and action from self-proclaimed ocean champions. In June, Norway announced new permits for offshore oil and gas drilling worth $18.5 billion, and proposed opening some 280,000 square kilometres of its waters to deep-sea mining, a nascent industry that risks wreaking havoc on poorly understood ocean ecosystems. Similarly, France, also the host nation for an upcoming UN Ocean Conference in 2025, is opposing a measure to exclude a destructive fishing practice called bottom trawling from marine protected areas in the European Union.

The EU itself seems to be operating two sets of policies. Successes it has chosen to highlight include a 37% decrease in fishing pressure — a measure of the extent to which a stock is being exploited — and a 22% increase in fish biomass in its waters between 2005 and 2020. This contrasts sharply with its actions elsewhere; it has been fighting conservation measures in the Indian Ocean that would curb chronic overfishing of yellowfin tuna. French and Spanish ships harvest up to one-third of tuna in these waters with the aid of fish-aggregating devices — large floating structures made of wood or plastic that attract fish, including juveniles, and are associated with unsustainable fisheries.

Other big maritime nations — China, India, Brazil and Russia — are facing major challenges in achieving SDG 14. But none has held itself up as an ocean leader. Conversely, Chile’s government is making strides. It has designated 41% of the country’s waters for protection, and, last year, the government proposed (albeit unsuccessfully) to revise the constitution, in part to bring in broader ocean-management measures, including more stringent controls on coastal salmon farming.

There’s still time to turn the ship around. Key to this will be the implementation of measures to hold nations accountable for their promises, for which Nature and others have previously advocated. This, in turn, needs better progress metrics. In this respect, researchers can and are playing a crucial part3. There’s also a need to finance help where it’s needed. According to one analysis, implementation of SDG 14 will require an extra $150 billion a year4. But implementing some SDGs will make funding available for others. Ending harmful fisheries subsidies, for example, should free up between $22 billion and $35.4 billion a year5.

Much of the extra funding required for SDG 14 has already been negotiated through other forums, such as the UN’s Green Climate Fund. And last December, as part of the Kunming–Montreal Global Biodiversity Framework, nations agreed to raise at least $200 billion a year by 2030 from public and private sources to fund biodiversity protection, both on land and in the water.

This isn’t just about dewy-eyed sentiment for our beautiful blue planet: the livelihoods of hundreds of millions of people depend on the oceans and the life they sustain. There’s much that scientists can do to achieve ocean sustainability. But to get SDG 14 back on track for 2030, world leaders must stand by the promises in their rhetoric.