Climate change is pushing
the world’s oceans toward a mass extinction event, according to
a new report published in Science late last month. The authors, Princeton’s Justin Penn and Curtis Deutsch, contend that without swift steps to reduce greenhouse gas emissions, the vast majority of all marine species could vanish over the next three centuries, with
dire consequences for the rest of life on Earth. These findings underscore the urgent need to take dramatic action against global warming and to reduce other anthropogenic strains on marine ecosystems. There is still time to limit the damage—but only if the world acts quickly.
As a terrestrial species, we often take the oceans for granted, ignoring their centrality to a stable and healthy biosphere and treating them as an inexhaustible repository of resources, as if they are impervious to human activity. In fact, climate change and human exploitation are fast degrading the marine environment, undermining the ecological foundations of our own survival.
The oceans have always played a central role in Earth’s climate system, but they have worked overtime since the start of the Industrial Revolution, absorbing 90 percent of the heat and one-third of the carbon dioxide generated by human activity. In so doing, they have insulated humanity from the worst effects of climate change, but at great cost. And now, the bill is coming due.
Oceans are now
warmer today than have been in recorded history, and are
30 percent more acidic than they were 200 years ago. Many ocean species, from microorganisms to large animals, are struggling with the heat stress, changes to ocean chemistry and lower oxygen levels associated with warm or acidic water. Those unable to adapt or relocate will disappear, and complex ecosystems will fall apart. Absent a course correction, the loss of
ocean biodiversity will rival that of the Permian Extinction, a mass extinction event 250 million years ago that saw the disappearance of 90 percent of ocean life. That event was also the product of global warming, albeit one of volcanic, rather than human, origin.
Some of the coming losses are inevitable, but
Penn and Deutsch estimate that 70 percent of ocean species can still be saved if the world holds the rise in global temperatures to 1.5 degrees Celsius above preindustrial levels, the goal set by the 2015 Paris Agreement on climate change. Currently, the world is on track to warm by 2.7 to 3.0 degrees Celsius. Limiting heating to
1.5 degrees Celsius will require achieving net-zero global emissions by 2050. Unfortunately, too many countries, including the United States, are
doubling down on fossil fuels rather than phasing them out.
To make matters worse, the human assault on oceans is not confined to climate change. Marine species and ecosystems are also endangered by overfishing and deep-sea mining, among other threats. According to the
United Nations’ Food and Agriculture Organization, 34 percent of wild fish stocks are overfished, up from 10 percent in 1974. Despite the efforts of regional fisheries management organizations, as well as the
United Nations’ 2016 Agreement on Port State Measures, illegal, unreported and unregulated fishing remains rampant, facilitated by the transshipment of illicitly harvested fish on the high seas or within states’ poorly policed exclusive economic zones.
Scientists estimate that industrial fishing has reduced large ocean fish to 10 percent of their previous numbers,
destabilizing complex food webs and ecosystems.
Overexploitation is encouraged by the unnecessarily large capacities of national fishing fleets, an unintended effect of the
$14 billion to $54 billion in government subsidies they receive each year. In 2001, the
World Trade Organization began laborious negotiations to curb these harmful subventions, a
commitment reaffirmed in the United Nations’ Sustainable Development Goals. After two decades of work,
WTO members have a draft agreement before them, which
WTO Director-General Ngozi Okonjo-Iweala hopes they will sign at their
upcoming ministerial conference scheduled for June. Like so much else of the WTO’s work, however, this agreement could become a
diplomatic casualty of the war in Ukraine.
Earth's oceans have insulated humanity from the worst effects of climate change, but at great cost. And now, the bill is coming due.
Marine biodiversity is also endangered by the quickening global race to exploit the untapped mineral riches of the deep seabed, a competition that threatens to destroy species and ecosystems on the ocean floor and damage the broader marine environment. Ironically, a
major impetus behind this competition is the surging demand for cobalt, nickel, rare earths and other elements needed to manufacture the electric batteries that will power our clean-energy future. Seeking to cash in on the post-carbon economy, mining companies are rushing to stake their claims on the seabed’s resources, and particularly to the large deposits of polymetallic nodules that litter the ocean floor in places like the Clarion-Clipperton Zone between Hawaii and Mexico. Several firms have already designed robots to harvest these nodules on an industrial scale.
The international organization charged with
drafting the regulations for this gold rush is the
International Seabed Authority, a small, independent body established under the 1982
U.N. Convention on the Law of the Sea. Unfortunately, recent
investigative reporting by the Los Angeles Times suggests that this authority is both out of its depth and the victim of regulatory capture, failing to balance its twin—and
admittedly conflicting—responsibilities of facilitating resource exploitation and ensuring ocean conservation. In June 2021, hundreds of marine scientists and ocean policy experts from
44 nations signed a petition demanding a moratorium on any commercial mining leases until the potential environmental impacts on fragile deep-sea ecosystems have been studied.
These and other threats to the marine environment underscore the urgency not only of dramatic emissions reductions, but also of improvements in ocean governance. A centerpiece of the latter must be the successful conclusion of a new high seas biodiversity agreement, which
I have written about before. In March, at the fourth negotiating session for such a treaty,
national delegations agreed to meet again later this year, with the goal of approving a high seas agreement that would promote the sustainable management and conservation of seas that are beyond national jurisdiction, an area encompassing some 64 percent of the world’s ocean area and 95 percent of its volume.
Between now and then, negotiators will need to hammer out final details on four main issues. These include the designation of marine protected areas, which are essential to prevent overfishing; rules governing environmental impact assessments, including for mineral exploitation; measures to ensure equitable benefit-sharing, including from marine genetic resources; and the terms of technology transfer and other forms of capacity-building for poorer countries. The treaty must also create multilateral mechanisms to implement these provisions, and it should also clarify the relationship between these new institutions and other existing, flawed bodies, including the International Seabed Authority and the multiple regional fisheries management organizations. If the negotiators are successful, they will have helped bring order to the currently ungoverned ocean commons and will have advanced the global goal of protecting 30 percent of the world’s oceans by 2030.
An improved multilateral framework to protect the oceans would have
a triple benefit,
scientists say. It would preserve marine biodiversity, increase the productivity of fisheries and enhance the capacity of the oceans to sequester carbon. A healthy planet, in other words, requires healthy oceans. Or as the acclaimed oceanographer Sylvia Earle has said, “No blue, no green.”
Stewart Patrick is the James H. Binger senior fellow at the Council on Foreign Relations and author of “The Sovereignty Wars: Reconciling America with the World” (Brookings Press: 2018). His weekly WPR column appears every Monday.
