Methane Removal Under the Paris Agreement

By Romany M. Webb

In the 2015 Paris Agreement, the international community agreed to “strengthen the global response to climate change” by limiting the “increase in global average temperatures to well below" 2 degrees Celsius above pre-industrial levels, and ideally to 1.5 degrees Celsius. As recognized in the Agreement, to stay within these limits, global greenhouse gas emissions must be rapidly reduced, “so as to achieve a balance between anthropogenic emissions by sources and removals by sinks of greenhouse gases in the second half of this century” — a situation commonly described as “net zero.” The need to reach net zero has prompted growing interest in developing strategies to remove greenhouse gases from the atmosphere. While greenhouse gas removal cannot substitute for emissions reductions, it is likely a necessary complement to them, required to offset residual emissions for which there are no feasible control technologies.

One suite of greenhouse gas removal techniques currently receiving attention targets methane in the atmosphere. A short-lived but highly potent greenhouse gas, methane is emitted through various human activities (e.g., agriculture and fossil fuel production), as well as from natural sources (e.g., wetlands). The natural emissions, in particular, are difficult to control and expected to increase significantly in coming years due to climate change. In theory, atmospheric methane removal could help to compensate for increasing natural methane emissions, as well as hard-to-abate anthropogenic emissions. Atmospheric methane removal should not, however, be used as an excuse to delay implementing feasible emissions reduction strategies where they exist.

Scientists have proposed a range of atmospheric methane removal techniques. All are still in the early stages of development and require further research, but could, in theory, accelerate the conversion of methane in the atmosphere into other chemical species with lower global warming potential (e.g., carbon dioxide). Initial research suggests that this could have significant climate benefits but, to date, atmospheric methane removal has received little attention in international discussions regarding climate change. It was not considered at all when the Paris Agreement was negotiated and, in the ten years since, has been raised only in passing in debates about how to operationalize the Paris Agreement Crediting Mechanism (PACM). While this is understandable given the early stage of development of the field, as interest in atmospheric methane removal grows, so too does the need to understand whether and how it fits within the Paris Agreement framework.

This paper provides the first comprehensive analysis of methane removal under the Paris Agreement. The paper explores the role that atmospheric methane removal might play in achieving the goals of the Paris Agreement (Part 3), whether parties to the Paris Agreement could rely on atmospheric methane removal as a climate change mitigation strategy under the Paris Agreement (Part 4), and the potential for atmospheric methane removal projects to participate in the PACM (Part 5).

Read the report, Methane Removal Under the Paris Agreement, in Columbia Law School's Scholarship Archive.