Interest in marine carbon dioxide removal (mCDR) has risen in the last decade as the deadlines to meet global climate temperature goals draw closer. The Intergovernmental Panel on Climate Change (IPCC) tells us that the 1.5°C and 2°C temperature targets outlined in the Paris Agreement require net zero emissions, which in turn requires some use of carbon dioxide removal (CDR). This doesn’t mean we can or should abandon emissions cuts. CDR is a complement to, but cannot substitute for, deep and rapid emissions reductions. But persistent failure to reduce emissions on a trajectory needed to meet climate goals has increased the need for CDR by loading our atmosphere with carbon pollution.
mCDR is a subset of a broader range of CDR approaches. mCDR seeks to leverage the ocean’s natural ability to uptake and store carbon dioxide from the atmosphere. This is logical place to explore – the ocean is the Earth’s largest natural carbon sink; it has absorbed approximately thirty percent of all carbon dioxide emitted since the industrial revolution and currently holds approximately fifty times more carbon than the atmosphere.
The Sabin Center has been at the forefront of an effort to analyze the legal framework for mCDR. Starting in 2021, we’ve published papers analyzing the international and U.S. legal framework applicable to four distinct approaches: ocean alkalinity enhancement, seaweed cultivation, artificial upwelling and downwelling, and ocean fertilization. During that time, interest has grown in a fifth approach: direct ocean carbon capture and storage (DOCCS).
DOCCS aims to directly remove some of the carbon in the ocean and thereby enable it to uptake additional carbon dioxide from the atmosphere. Further research is needed to fully evaluate DOCCS, but early studies suggest it has significant climate mitigation potential. However, DOCCS at this scale would require the construction of new energy-intensive facilities to take in, process, and discharge water. Moreover, the captured carbon dioxide would need to be stored in a way that prevents its release into the atmosphere (e.g., via injection into underground geologic formations). All of these activities could pose risks, which must be weighed against the potential climate and other benefits of DOCCS in deciding whether and how to move forward.
The legal framework for DOCCS activities will have a major bearing on these questions. Over the past month, the Sabin Center has published two papers detailing the existing legal framework. The first paper explores the governance of DOCCS under international law. The second paper considers the application of U.S. domestic law to DOCCS. Together, the two papers offer the first comprehensive review of the existing legal framework for DOCCS and begin to identify key uncertainties, gaps, and shortcomings that will need to be addressed to ensure robust governance of the practice.
Overview of DOCCS
DOCCS aims to increase the ocean’s natural ability to uptake carbon dioxide from the atmosphere by first directly removing carbon dioxide from ocean water, and then allowing it to “refill” with carbon dioxide. To do this, closed systems are used to process ocean water or, in some cases, brines from desalination or other industrial operations. Within these closed systems, electrolysis is used to strip the fluid of carbon dioxide, which then needs to be stored in a manner that will prevent its re-release back into the atmosphere (e.g., by injecting it into geologic rock formations). The remaining fluid, which is now depleted of carbon dioxide, is then allowed to refill with carbon dioxide from the atmosphere.
In some DOCCS processes, this refilling step is performed within the closed system by, for example, bubbling air through the fluid before it is released back into the ocean (see a diagram of one example on page 5 here). Other DOCCS processes discharge carbon-depleted water into the ocean, where it should naturally uptake additional carbon dioxide from the atmosphere (see a diagram of an example here).
Further research is needed to evaluate DOCCS, but DOCCS shows promise in carbon removal potential. Because the carbon captured and geologically stored can be readily quantified, DOCCS does not pose the same accounting challenges as some other CDR approaches. Further, early studies suggest DOCCS could result in the storage of billions of tonnes of carbon dioxide annually. If this potential is realized, DOCCS could play a significant role in removing some of the more than 1.6 trillion tonnes of carbon dioxide humans have emitted since the industrial revolution.
Deploying DOCCS at this scale would, however, require the development of large amounts of new infrastructure and considerable use of energy, as noted above. This includes the construction of facilities to take in, process, and discharge water and infrastructure for handling, transporting, and storing carbon dioxide.
All of this could have adverse impacts on communities and the environment. For example, discharging water after processing could harm nearby water ecology and marine organisms. Transporting large amounts of carbon dioxide may require the development of new pipelines, which could require land clearing and/or have other adverse environmental impacts. There is also the potential for leakage of carbon dioxide from pipelines and other facilities. Careful siting, design, and operation of DOCCS systems is essential to mitigate these risks.
International legal Framework
A large body of international law could apply to DOCCS research and deployment. This includes international agreements addressing climate change, like the UN Framework Convention on Climate Change (UNFCCC) and the Paris Agreement, which require parties to take actions to mitigate climate change by, among other measures, enhancing carbon dioxide sinks. The definition of sinks is broad enough to include CDR approaches like DOCCS, but the climate agreements allow countries flexibility in determining exactly what strategies they will employ as part of their national mitigation plans.
Ocean management agreements, like the UN Convention on the Law of the Sea (UNCLOS), the Agreement under UNCLOS on the Conservation and Sustainable Use of Marine Biological Diversity of Areas Beyond National Jurisdiction (BBNJ Agreement), the Convention on the Prevention of Marine Pollution by Dumping of Wastes and Other Matter (London Convention), and the Protocol to that Convention (London Protocol) are also relevant to DOCCS. These agreements aim, among other things, to limit marine pollution which DOCCS could cause (at least in some circumstances). Parties to the London Convention and London Protocol have issued a series of decisions and statements on marine geoengineering broadly and are beginning to think about specific activities like DOCCS. Similarly, the parties to other environmental protection treaties, like the Convention on Biological Diversity have also issued decisions on geoengineering activities, which could apply to DOCCS.
Alongside these international agreements, rules of customary international law, including those requiring prevention of significant harm to the climate system, and rules governing environmental impact assessments, might also be relevant to DOCCS.
U.S. Legal Framework
The U.S. has been a focal point of early exploration of DOCCS technologies. Several start-up companies proposing to undertake DOCCS projects have formed in the country. And field trials testing different DOCCS technologies have taken place in California and Washington state. Domestic legal structures will have a major bearing on whether, where, when, and how such activities can be scaled up to larger deployments in the U.S. Similar to other mCDR technologies, the application of U.S. law to DOCCS is complex, with many potentially relevant federal, state, local, and tribal laws. The applicable legal requirements for DOCCS projects in the U.S. depend on the specifics of each project, with key distinctions based on the location and the DOCCs process used.
Siting DOCCS facilities will bring different legal requirements depending on whether the facilities are sited on land, in state waters, or in federal waters. Regulation of the siting facilities on land will depend partly on whether the land is private or publicly owned. For projects in state waters, coastal states often require a lease prior the construction of any facility that will be attached to the seabed, among other requirements. And federal law limits the type of activities that can use the seabed beneath federal waters, with yet-to-be-issued regulations on activities related to subseabed carbon dioxide injections.
Discharging processed water into the ocean will be governed primarily by the Clean Water Act and associated regulations, but different requirements may apply depending on the precise makeup of the discharged water. Further clarification by federal agencies or courts may be needed to ensure the precise application of the Clean Water Act to DOCCS discharges, and to ensure that similar activities with similar risks are not governed differently.
Regulation of post-capture transportation of carbon dioxide depends on whether the project utilizes pipelines, ships, road, and/or rail infrastructure. Utilizing pipelines may have energy and cost advantages over other forms, but that would in turn require new construction and associated regulations. Though the U.S. had about 5,300 miles of carbon dioxide pipelines at the time of writing, very few connected to the coast, and none were offshore.
And regulation of geologic storage turns on whether the storage is on land or in state ocean waters versus in federal ocean waters. Storage below land or beneath state ocean waters will be governed primarily by the Environmental Protection Agency’s Underground Injection Control program. And injections into federal ocean waters will be primarily governed by the Outer Continental Shelf Lands Act, with yet-to-be-issued regulations for such injections.
Conclusion
When and how the existing international and U.S. legal framework will apply to DOCCS is uncertain, in part due to the newness of the technology. The relevant international instruments were adopted prior to any discussion of DOCCS and were thus designed to govern other activities. In the U.S., federal and state laws overlap, creating complexity for DOCCS project developers. A dedicated, comprehensive legal framework could help overcome these challenges. The authors have previously written about the potential for an mCDR-specific regulatory framework in the U.S. Further research may identify whether this framework is well-tuned for DOCCS, and whether further legal development is needed for a DOCCS-specific framework.
This blog has provided a brief summary of some of the findings of our two papers, where they are explored in significantly more depth. As explained above, the papers offer the first comprehensive review of the existing legal framework for DOCCS. They are, however, a starting point. Further analysis is needed to fully evaluate the international and U.S. frameworks. This is especially true for tribal, state and local requirements for DOCCS projects in the U.S. Further, identifying existing law is a starting point towards analysis of the appropriate legal frameworks for DOCCS going forward, to ensure that such activities proceed in a safe, responsible, and just way.
The first paper, The Legal Framework for Direct Ocean Carbon Capture and Storage (Volume 1: International Law), is available here.
The second paper, The Legal Framework for Direct Ocean Carbon Capture and Storage (Volume 2: The United States), is available here.
Korey is the senior fellow in carbon management and negative emissions at the Sabin Center for Climate Change Law
