Atmospheric Methane Removal Approaches

Enhanced Methanotrophs

Rising temperatures are increasing the risk of natural systems releasing methane, which would drive further warming. Existing efforts towards reducing anthropogenic greenhouse gas emissions and removing atmospheric carbon dioxide are crucial, but may be insufficient to maximally decrease the chance of, and then possible impact of, these risks. Atmospheric methane removal approaches are being researched to determine how to remove methane from the atmosphere faster than natural systems alone, in order to help lower peak temperatures and counteract some of the impacts of large-scale natural systems methane releases.

Atmospheric methane removal, should any approaches prove highly scalable, effective, and safe, could help address some of the current 0.5°C—and rising—of methane-driven warming. All proposed atmospheric methane removal approaches are at a very early stage today: some ideas have been proposed, some are being researched in laboratories, but none are yet ready for deployment. Spark believes that accelerating research to develop and assess which, if any, of these approaches might be possible and desirable is an important additional risk mitigation strategy.

A number of atmospheric methane removal approach ideas have been raised—including
methane-oxidizing bacteria
, which is currently
, with major breakthrough innovations required to change this
This approach, based on early analysis, will likely require multiple breakthroughs in order to feasibly address atmospheric methane levels. It may hold the most promise if it also delivers separate benefits (e.g. for climate or pollution), as part of systems deployed for other primary reasons, or to address low-concentration methane sources.

Enhanced Methanotrophs


Methanotrophs, bacteria and archaea that oxidize methane, provide a natural methane sink. Some strains of methanotrophs are more effective than others at oxidizing atmospheric methane while sustaining their growth. It may be possible to engineer methanotrophs to improve their ability to oxidize atmospheric methane with higher growth rates and reduced other impacts, like nitrous oxide production, compared to naturally-occurring strains. Introduction of these strains could enhance the natural methanotrophic sinks of methane in soils, termite mounds, or on plants.

These approaches may warrant additional exploration in natural systems and/or agricultural settings. This overview focuses on the subset of methanotroph enhancements that have potential for a net uptake of atmospheric methane. Applying any of these approaches for atmospheric methane removal is at the early stage of conceptualization. Little is known about the potential effectiveness and side effects.


Learn more about how we evaluate cost plausibility and climate impacts

There is insufficient peer-reviewed literature on enhanced methanotrophs for methane removal to assess feasibility. Moreover, populations of methanotrophs have evolved to be adapted well to the methane concentrations that they frequently experience, from atmospheric concentrations (2 ppm) for upland soils to much higher concentrations in landfill soils and the surface soils in wetlands and rice paddies, where methane diffuses upwards from deeper methanogenesis sources (Whalen 1996, Whalen 1990, Conrad 2007). Hence, it is unclear how engineered organisms would have mechanisms that enable greater methane oxidation rates than those of natural soil populations.

Little is known about the cost per unit of methane uptake. Cost will depend on the methane uptake rate, expenses related to the dispersal of methanotrophs and those related to the enhancement process itself, and ongoing monitoring of the effectiveness.


Learn more about how we evaluate scalability

There is insufficient literature on enhanced methanotrophs for methane removal to assess scalability. The potential scale may depend on the suitability of the land for methane uptake enhancement, constraints in culturing and dispersing methanotrophs, and raw material availability.

As a benchmark, a net annual uptake of 10 million metric tons of methane (830 Mt CO2e using GWP20) would require enhancing the current global methane soil sink by 20% to 100%. This requirement might be somewhat less if methanogenesis suppression co-benefits are factored in. 

The scale of enhanced methanotroph deployment may be limited by environmental concerns, competition with natural methanotrophs, or the availability of suitable land.

Health & Environmental Considerations

Interventions in natural or agricultural systems must be approached very carefully. Introducing foreign bacteria into a natural or agricultural environment, whether natural or genetically modified, may have impacts on the microbial structure, soil structure, health, and nutrient profile, affecting plant, fungi, and animal health. Genes added by transgenic methods may transfer to other bacteria through horizontal gene transfer, though this risk can be mitigated somewhat by “suicide genes”. Genetic modification may also have impacts on nitrous oxide co-generation.

Assessing such impacts through lab testing, modeling, and small-scale field tests would be necessary before deployment, as would ongoing monitoring of effects after deployment. 

Genetically modified microorganisms have been deployed for pollutant degradation, environmental monitoring, and other applications. Regulatory regimes vary by country. In the U.S. they are regulated by the EPA. 

Methanotrophs technology transfer would face other particular challenges connected to land use. Over 40% of ice-free land has been modified by humans, primarily for agriculture. Agricultural soils generally have lower rates of methane uptake (by as much as a factor of 7) relative to native soils, which may present an opportunity to enhance methane uptake on agricultural land without directly affecting natural ecosystems. However, it is important to understand why methane uptake rates are lower in well-drained agricultural soils, such as soil compaction that reduces diffusion of atmospheric methane into the soil, competitive inhibition of methane oxidation by ammonium, lack of sufficient micronutrients like copper, or changes in microbial communities.

Introducing methanotrophs in agricultural settings or natural landscapes around the world would have to contend with various cultural norms, traditions, policy mindsets, capacity limitations, and scarce finances.

Learn More

State of Research
References and Resources
Thank you to
Simon Guerrero Cruz (Assistant Professor, Asian Institute of Technology, Environmental Engineering and Management program)
for their contributions to, and review of, this content.
This is live and evolving content, we are always open to well-referenced updates and suggestions, which can be shared here.

Explore Other Potential Approaches

Approaches Overview

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