Legal Considerations for Atmospheric Methane Removal

Scientists are beginning to investigate atmospheric methane removal approaches, which would accelerate the conversion of methane to a less radiatively potent form or physically remove methane from the atmosphere and store it elsewhere. Developing and, if appropriate, deploying atmospheric methane removal approaches will require an understanding of relevant legal considerations and governing structures that could impact whether, when, where, and how specific projects take place. This paper examines the treatment of atmospheric methane removal approaches under international and U.S. domestic law. The paper focuses on five atmospheric methane removal approaches that are currently being investigated: (1) atmospheric oxidation enhancement, (2) ecosystem uptake enhancement, (3) surface treatments, (4) methane reactors, and (5) methane concentrators. Scientists often divide the five approaches into two broad categories based on whether they involve “open” systems (i.e., approaches 1 to 3 above) or “closed” ones (i.e., approaches 4 and 5). This paper adopts that categorization but also distinguishes between approaches based on other factors that are legally significant. The paper does not discuss techniques for reducing methane emissions (e.g., flaring or other techniques that address high-concentration streams) and does not cover hydrogen emissions, even though they can affect atmospheric methane levels. Instead, this paper focuses on the removal of methane from the atmosphere and related legal issues under international law and domestic U.S. law, with a particular focus on U.S. federal law.\nThere is no specific legal framework governing atmospheric methane removal activities either at the international level or domestically in the United States. However, a variety of general environmental and other U.S. and international laws may apply to field research and deployment. The applicability of different laws will depend on a range of factors, including the specific nature of the activities (e.g., whether they involve open or closed systems), the purpose for which they are conducted (e.g., whether they involve research or commercial activities), where they take place (e.g., on land or in the ocean), and the nature and location of their impacts.