The Sixth Assessment Report of the Intergovernmental Panel on Climate Change underscores the need for carbon dioxide removal (“CDR”) to complement emissions reductions in meeting global climate targets. Ocean-based CDR strategies, which aim to increase the ocean’s natural carbon sink capacity, are gaining attention. One such strategy, ocean alkalinity enhancement (“OAE”), involves adding alkaline substances to seawater so as to increase its ability to absorb atmospheric carbon dioxide (“CO2”) and mitigate ocean acidification. Early research suggests OAE has significant potential to remove CO2 but key questions remain about its efficacy and impacts. Further research into OAE, including controlled field trials, is needed to answer those questions and determine what role (if any) OAE might play in efforts to address climate change. Some research is already occurring in the U.S. and more is planned. There are, however, significant questions as to how that research will be regulated under domestic (U.S.) law. One key question relates to federal preemption and state authority, namely do federal laws preempt state regulation, and, if not, to what extent can states regulate OAE activities? A recently published Sabin Center report answers this question.

OAE 101

OAE involves adding alkalinity to the ocean, in order to convert CO2 in the water into dissolved inorganic carbon. This, in theory, allows for a greater influx of atmospheric CO2 into the ocean. OAE also has the potential to counteract ocean acidification, which could help in the restoration and preservation of ecosystems threatened by the acidification.

Two of the most commonly discussed approaches to OAE are: (1) a mineral-based approach, whereby ground alkaline rock is spread on the surface of the water, and its dissolution leads to an increase in the pH of the water; and (2) an electrolytic approach, where the alkalinity of the ocean is increased through electrochemical reactions. These different approaches to OAE may have differing legal consequences.

A Patchwork of Federal Regulatory Oversight

Currently in the U.S., OAE, like other emerging CDR methods, does not fall under a dedicated regulatory framework. Instead, it is regulated under general environmental laws that were enacted several decades ago to address problems, such as air and water pollution.  The result is a complex and sometimes unclear regulatory landscape.

Our new report discusses various federal laws that may apply to OAE, including the Marine Protection, Research, and Sanctuaries Act (“MPRSA”) and the Clean Water Act (“CWA”). Each law addresses a different environmental problem – the MPRSA governs ocean dumping, while the CWA regulates pollution of navigable waters – but both could apply to certain OAE activities.

The MPRSA is the primary federal law governing OAE activities that involve dispersing alkaline materials into the ocean via vessels. Any person wanting to disperse alkaline materials from a vessel must first get a permit from the Environmental Protection Agency (EPA). EPA recently made a tentative determination to issue a research permit under the MPRSA for an OAE project proposed to be conducted off the Massachusetts coast.

Notably, the MPRSA does not apply to all OAE activities. For example, mineral-based OAE projects that do not involve the use of vessels are excluded, as are electrochemical approaches. Those activities will, instead, likely be regulated under the CWA (and potentially other federal laws).

The CWA regulates pollutant discharges from “point sources” (conveyances like pipes) into navigable waters of the United States. OAE projects that involve the dispersal of alkaline minerals into ocean waters via pipes from the shore would likely be covered by the CWA, as would electrolytic approaches to OAE. The CWA establishes multiple permitting regimes that could have implications for OAE projects. For example, some projects may require a permit the National Pollutant Discharge Elimination System (“NPDES”) program in Section 402 of the CWA, or a permit from the Army Corps of Engineers under Section 404 of the CWA. NPDES permits must abide by water quality standards. This is especially relevant to OAE activities, as changes to pH could affect compliance with applicable water quality standards.

The Sabin Center report also covers the Rivers and Harbors Act, which could apply to OAE activities if they obstruct navigable waters. There are other laws that apply to OAE as well, however their preemptive effects are more limited. These have been covered in greater depth in other publications.

The Role of States and Federal Preemption

While federal law provides overarching regulation of OAE, particularly for activities involving vessels, states still do retain some regulatory power.

For projects covered by the MPRSA, that Act includes a broad preemption clause, which limits both the application of other federal laws (including the CWA) and state regulation. States cannot permit or authorize the transportation of materials through vessels for the purposes of dumping in ocean waters. There is, however, potential for other state regulation. For example, states could ban OAE activities altogether or impose more stringent requirements (above and beyond those imposed under federal law) on OAE projects within their waters.

The CWA’s cooperative federalism model allows states to play a more active role in regulating OAE activities covered by that Act. States can regulate water quality and enforce stricter environmental standards than those set at the federal level under the CWA. States can set their own State Pollution Discharge Elimination System permits with authorization from EPA. The CWA thus leaves considerable scope for state regulation of OAE activities. Any state regulatory regime must, however, be at least as stringent as federal regulation. That is, the federal regulators establish a “floor,” which states have the ability to go beyond.

As the report discusses in further detail, there are other opportunities for states to oversee OAE activities, including the Coastal Zone Management Act (“CZMA”). Read the full report here.