Carbon dioxide released into the atmosphere and absorbed by water lowers its pH level, making the ocean more acidic and less able to sustain life. In 2009 a group of scientists included this ocean acidification (OA) as one of nine planetary boundaries that must remain within safe bounds if the earth is to remain stable and resilient. That study recognised that ocean health is integral to the overall health of the planet. A more recent study concluded that by 2020 the planetary boundary for OA had already been crossed. It is the seventh of the boundaries to have been breached.
For over two decades, governments and international organisations have recognised the danger that OA poses to marine life, and by extension to economies and societies. Supported by a large volume of scientific research detailing the threat, measures to combat OA have been incorporated into numerous national policies and international agreements, including the United Nations Sustainable Development Goals (SDGs). But the crossing of the planetary boundary is a clear indicator that those efforts have failed.
Policy fragmentation, at both international and national levels, is a major reason for the lack of progress on OA. Seen in conflicting objectives, duplication and weak accountability for results, such fragmentation is, an issue across ocean management as a whole. Many experts believe that a more holistic, systems-based approach to ocean management can integrate OA action more effectively alongside parallel efforts to address other stressors of ocean and planetary health. In this article, they discuss why such an approach has potential to eventually turn the tide.
The case for ocean and planetary stewardship
It is self-evident why the ocean must be treated as a single system, says Robert Blasiak, associate professor at the Stockholm Resilience Centre at Stockholm University. “The ocean is inextricably linked to everything on the planet—to societies and communities, from their nutrition to their sense of place and spiritual connections and to the biosphere as a whole,” he says. “So we have to address threats to ocean health within the context of threats to the planet as a whole. OA is among the biggest threats to the ocean and we can’t disconnect it from atmospheric carbon emissions, climate warming and other perils.”
Johan Rockström, director of the Potsdam Institute for Climate Impact Research and one of the authors of the planetary boundaries framework, also makes clear the link between ocean health and planetary health. “The ocean regulates the climate system and fundamentally shapes the way the biosphere is configured. In essence, the ocean regulates liveability on earth. If the ocean released all the heat it has captured from our burning of fossil fuels, the temperature in our atmosphere would rise by over 20°C and make the planet uninhabitable.”
The implications of this for ocean policymakers are clear, says Sarah Cooley, executive director of Earth Science Information Partners (and formerly OA programme director at America’s National Oceanic and Atmospheric Administration). “They must fully embrace that humans are part of the ecosystem,” she says. “Any actions taken to address OA or other stressors are going to have effects not just elsewhere in the ocean but on humans as well. That makes it very complex to know what the right actions are to take.”
The fragmentation of ocean policy is simultaneously a source and manifestation of the complexity Dr Cooley describes. The UN Framework Convention on Climate Change, the Convention on Biological Diversity, the Biodiversity Beyond National Jurisdiction agreement and the SDGs all mandate action to improve ocean health, including by combatting OA. “There isn’t, however, a strong mechanism to find opportunities for synergies between these,” says Steve Widdicombe, director of the Sharjah Marine Science Research Centre at the University of Khorfakkan. “All of these treaties are important and work hard to deliver positive outcomes, but they could be so much more effective if they were consciously aligned.”
Dr Rockström agrees: “Those international agreements all play important roles in ocean management. They are interconnected to some extent, but we need a mother framework for all of these thematic and sector components, because ocean management is so closely tied to land management and to climate management.”
Disjointed OA action
The policy fragmentation afflicting OA action can only be understood within this context. OA isn’t even mentioned in some major international agreements, says Dr Cooley. “the UN Convention on the Law of the Sea, for example, and policies dealing with shipping or pollution are silent on carbon dioxide because they were developed well before OA or carbon emissions were recognised as threats. So we have a patchwork of laws and policies that have arisen over time, and they address different parts of marine governance.”
The inherent complexity of OA as a field of science and its intertwining with other fields has led policymakers to try and break up OA action into manageable pieces. This is also often the case at national levels, where in some governments OA responsibilities are distributed among several agencies, leading to duplication of effort and unclear accountability. “It makes joined-up thinking on OA or ocean health more widely very difficult to achieve,” says Professor Widdicombe.
Over the past decade, the governments of several American states have sought to overcome that fragmentation by creating dedicated OA action plans, with a single departmental body given responsibility for co-ordinating the disparate efforts of the others. Their achievements have thus far come more in the policy realm—for example by securing passage of legislation or mobilising funding for climate adaptation initiatives—than in actual reduction of OA levels in their waters. (The latter outcome is unlikely as long as global carbon emissions, the primary driver of OA, are not reduced.)
But, as Dr Cooley points out, America is an unusual example of fragmentation actually helping the cause of ocean action. “Individual states like Washington, Oregon, California and others have stepped up and led on OA when other states or the federal government have been unable, or found it inexpedient, to do so,” she says. “But we need to find a way to cross-wire or cross-link all the disparate OA policies and initiatives because of how OA interacts with so much else on the planet. Creating a top-down, unified OA policy isn’t necessarily the answer.”
A systems approach and OA
“It makes no sense to delay any longer bringing the different strands of ocean management together in a system of ocean stewardship,” says Professor Blasiak. “The science on OA, on warming, on deoxygenation and on other stressors is solid. Ocean health is increasingly a co-ordination challenge rather than a scientific challenge.”
A systems approach to ocean management would be distinguished by its recognition of the highly interconnected nature of the threats to ocean health. Following that recognition is the imperative for stakeholders to gauge the system-wide impacts of any policy or initiative, not just the impact on an individual stressor. For example, restricting fishing in designated coastal waters and the creation of marine protected areas (MPAs) improves their resilience against OA, but it could also lead to overfishing in adjoining waters. Coastal ecosystem management can, if it disturbs sediment layers, release stored carbon dioxide, leading to increased acidity levels. Higher acidity can also happen when land-based adaptation measures increase the flow of nutrients into coastal waters and thereby increase eutrophication. “Joined-up ocean management would reduce the likelihood of unintended effects resulting from otherwise well-intentioned measures,” says Professor Widdicombe.
Real examples of such an approach at governmental level are hard to find. But some organisations have taken steps to apply systems thinking that integrates actions across different parts of the ocean ecosystem. One is the OSPAR Commission, which manages work undertaken under the OSPAR Convention. The latter is an agreement between 15 European countries and the European Union government that regulates the sustainable use of the marine environment in the north-east Atlantic. Among several action areas, it also now integrates efforts to combat OA.
Dr Cooley believes America’s National Ocean Policy, developed under Joe Biden’s administration and which also addresses OA, has the potential to deliver unified and comprehensive management of the country’s coastal waters. But the prospects for its implementation under Donald Trump’s administration remain unclear.
From ideal to reality
America’s retreat from global climate change commitments in the past year darkens the prospect of ocean stewardship gaining ground internationally any time soon. But Dr Rockström is optimistic that its time will come, as will that for planetary stewardship. “Ocean stewardship is not a fantasy, and neither is the prospect of planetary stewardship,” he says. “We have global compacts such as the SDGs that commit nations to taking actions that protect the ocean, the climate and the entire planet. The UN is behind these and is capable of mobilising even more resolute action. I don’t think we’re far away from recognising the need for collective stewardship of the earth system, focusing on a world that develops within planetary boundaries.”
Back to Blue, February 2026. Article.
