Research into methane removal continues to gain momentum as more experts recognize methane’s importance in the climate system and the risk of increased methane emissions from natural systems as the planet warms. “Methane removal” refers to methods of breaking down atmospheric methane faster than natural systems would alone to help lower peak temperatures and to counteract some of the potential impact of rising natural methane emissions. Last week, the Sabin Center for Climate Change Law at Columbia University released a new report, Removing Methane via Atmospheric Oxidation Enhancement: The Legal Landscape, that provides a first-of-its-kind exploration of the international and domestic (US) legal frameworks governing the field, with funding support from both ClimateWorks and Spark. The Sabin Center is continuing work in this field with analyses of other categories of methane removal approaches. 

Atmospheric oxidation enhancement (AOE) is one of several proposed categories of approaches to remove methane after it’s been emitted and mixed into the atmosphere. Proposed AOE approaches would increase the overall atmospheric methane sink using atmospheric oxidants, such as chlorine and hydroxyl radicals, to mimic the natural breakdown of methane. The atmospheric concentration of methane is determined by the balance of sources and sinks, thus amplification of natural sinks — such as atmospheric oxidation which accounts for approximately 95% of methane loss — holds potential for reducing rising methane levels. 

The Sabin Center report describes important aspects of the current legal frameworks that may be relevant for AOE:

• “AOE law is underdeveloped, but it is already complex.” No existing laws were designed for the explicit purpose of governing AOE, but similar to some carbon dioxide removal techniques, federal laws that seek to protect the environment and limit human perturbation of it will still apply and govern AOE. 
• Many international agreements, rules of customary international law, and traditional domestic environmental laws will “be implicated by and govern” AOE approaches. This emerging field will not be a “wild west.” Any AOE research should be developed in careful compliance with applicable laws and regulations. 
• The laws relevant to AOE will vary depending on the approach being explored. Different laws may apply to stationary methods of AOE than to mobile methods. Implementing AOE via fuel additives in ships or planes would implicate additional regulatory schemes. Small-scale research may raise different — and potentially less restrictive — legal considerations from a hypothetical future deployment. AOE methods are not subject to a one size fits all legal framework in large part because the proposed methods and their potential field trials differ considerably. 

Spark is grateful to the report’s authors, Romany Webb, Korey Silverman-Roati, and Martin Lockman, for taking on this groundbreaking work and clarifying the existing legal framework for AOE. With its partners, Spark will continue supporting work to understand which — if any — methane removal approaches may be viable and how they could help to mitigate sources of unmanaged climate risk.