Methane Action is a non-profit organization with a unique mission: Identify solutions that can rapidly reduce atmospheric methane concentrations to pre-industrial levels, and ensure their implementation, for the benefit of both present and future generations. Methane Action’s goal is to see atmospheric methane, a potent greenhouse gas, cut in half from its current dangerous concentration of 1.9 parts per million (ppm) to below 1 ppm, within a decade, thereby significantly reducing global warming. To that end, leading scientific experts, climate advocates, environmental lawyers, philanthropists and policy experts formed Methane Action, and are actively collaborating to address the growing methane crisis.


The Methane Crisis

The time for aggressive action to lower atmospheric methane levels has arrived. Here’s why:

  • Methane has at least 84 times the greenhouse-gas potency of carbon dioxide over a span of 20 years.[1]
  • Methane levels in the Earth’s atmosphere are now rising rapidly again after a brief plateau from 1999 to 2006, and scientists are unsure why. Methane has a relatively short half-life in the atmosphere of 9.1 years. But methane emissions are rising so fast that atmospheric methane is at record highs – 1.9 ppm, double pre-industrial levels –  and climbing fast.
  • Earth has lost 95% of the oldest, thickest Arctic Sea ice. Ground temperatures above the Arctic Circle reached 118 degrees Fahrenheit in July 2021. As more Arctic permafrost thaws and dark Arctic waters absorb more heat, the risk grows that permafrost and subsea methane deposits could escape.
  • High atmospheric methane concentrations could be the single biggest factor thwarting the collective effort of countries around the world to keep global warming below 1.5 degrees Celsius[2] under the Paris Climate Agreement.[3] The August 2021 United Nations IPCC report showed that global warming from methane from 2010 to 2019 was two-thirds that due to carbon dioxide.
  • Stopping anthropogenic methane emissions is critical and will help reduce atmospheric methane concentrations but even this won’t get atmospheric methane down to safe levels. For that, methane must also be removed from the atmosphere.

A Promising Methane Solution

Nature removes methane continuously in the troposphere via two “sinks”: the hydroxyl radical (°OH)[4] and the chlorine atom (Cl)[5]. Hydroxyl radicals account for roughly 90% of methane removal through natural oxidation, and chlorine accounts for another 3 or 4%. But nature’s oxidation process cannot keep up with today’s vast methane emissions from anthropogenic and natural sources, both of which are intensifying as the planet warms.  The resulting atmospheric methane buildup increases the risk of triggering dangerous climate feedback loops.  But the chlorine atom could, with a little assistance, potentially accelerate natural oxidation of methane. Chlorine atoms react with methane 16 times faster than the hydroxyl radical does, so generating more of them could be a highly efficient, natural way to remove tropospheric methane.[6]

Enhanced Atmospheric Methane Oxidation (EAMO)

Methane Action is currently helping coordinate and collaborating with an international network of scientists researching and testing ways to increase the natural methane oxidation rate through the chlorine pathway. When the sun shines on airborne sea salt particles, chlorine atoms are generated naturally through photocatalysis. One proposal is to add a small amount of iron to sea spray aerosols. The iron will react with chloride from saltwater forming iron chlorides that absorb sunlight to produce more chlorine atoms. As chlorine atoms react with methane, the main products are water and carbon dioxide. Eventually the sea salt and iron particles would fall back into the ocean where iron would help fertilize the growth of phytoplankton.

This approach is an example of “enhanced atmospheric methane oxidation” or EAMO. It was first investigated in 2015 with smog chamber lab tests, which simulated photocatalysis and found that adding iron to salt aerosols (ISA) increased the number of chlorine atoms generated by at least an order of magnitude. Those results are now being validated in lab tests at the University of Copenhagen directed by Professor Matthew Johnson, a leading atmospheric chemist.

As lab testing continues, climate scientists, marine biologists and other experts collaborating with us are also designing ways of field testing this EAMO technology in a tightly controlled manner. Field tests would obtain prior approvals by appropriate government authorities. Marine fuel oil combustion from shipping is currently the main source of soluble iron above the oceans,[7] and ships’ exhaust plumes may already be causing some EAMO effect. Our first field test is therefore to determine whether the effect is occurring, and if it is, to notify authorities so international regulations can take it into account.

EAMO technologies build on the atmosphere’s natural cleansing process. Iron salt aerosol for example stimulates natural methane oxidation and has no known negative side effects for people or the planet. But Methane Action takes safety very seriously and has commissioned an independent environmental impact assessment of ISA, which is now underway. We’re committed to conducting thorough environmental impact assessments for all methane removal technologies we think are promising. We also support broad-based, inclusive processes to enable stakeholders, affected communities, advocates, and experts to weigh in meaningfully before any methane removal technology gets deployed at scale.

Based on what we’ve learned so far, we believe EAMO holds powerful climate benefits. Combining it with aggressively mitigating methane emissions could cut atmospheric methane deeply and rapidly. Cutting methane concentrations in half would roll back global warming (i.e., radiative forcing from greenhouse gases in the atmosphere), reducing climate forcing by one-sixth, saving countless lives and ecosystems, and giving the world more time to succeed in drawing down other greenhouse gases to safe levels. Lowering atmospheric methane concentrations would also generate additional co-benefits, such as boosting crop yields and reducing ground-level ozone, which improves air quality and public health.

Once proven safe and effective and accepted by stakeholders, EAMO could be implemented with small amounts of iron over the ocean to efficiently reduce atmospheric methane levels. It could also mitigate otherwise hard-to-mitigate methane sources, such as rice paddies, where adding iron could lower methane emissions and boost the rice crop’s nutritional content.

 Methane Action works to evaluate all methane removal technologies according to safety, effectiveness, equity, scalability, affordability, and other vital considerations, and to advance best governance practices for methane removal. In addition to EAMO, scientists in our networks are also exploring the potential of other scalable methane removal technologies, such as adding zeolites[8] to direct air capture facilities or using photocatalysis[9].

Your Support Powers Our Work

Thanks to the generosity of our supporters and partners, Methane Action has secured initial funding for our operations, as well as partial funding for the work of our scientific advisors. Currently we are seeking additional funding to:

  • Continue prototype testing to validate proposed methane removal technologies;
  • Design and build new prototypes for field testing and deployment;
  • Evaluate test results and disseminate them to relevant scientific and industrial field leaders worldwide;
  • Develop a public engagement and policy framework for governance and oversight to facilitate deploying methane removal technologies, and scaling them up as needed; and
  • Design and conduct a broad, public-facing communications campaign on the methane crisis and its solutions.

To learn more, please contact Methane Action CEO Daphne Wysham, daphne@methaneaction.org, (503)310-7042, 211 Taylor St., Suite 403E, Port Townsend, Washington 98368

Click here to stay updated on our progress or to get involved.


[1] Intergovernmental Panel on Climate Change. (2014). Myhre, G., D. et al. (Eds). Anthropogenic and Natural Radiative Forcing. In Climate Change 2013 – The Physical Science Basis: Working Group I Contribution to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change (pp. 659-740). Cambridge: Cambridge University Press. doi:10.1017/CBO9781107415324.018. 

[2] Hansen, J., et al. (2017). Young people’s burden: requirement of negative CO2 emissions. Earth System Dynamics, 8(3), 577-616.

[3] The English text of the Paris Agreement can be found here: https://unfccc.int/sites/default/files/english_paris_agreement.pdf

[4] Atkinson, R., & Arey, J. (2003). Atmospheric degradation of volatile organic compounds. Chemical Review, 103(12), 4605-4638.

[5] Wang, X., et al. (2019). The role of chlorine in global tropospheric chemistry. Atmospheric Chemistry and Physics, 3981-4003.

[6] Witmer J., et al. (2015). Iron(III)-Induced Activation of Chloride and Bromide from Modeled Salt Pans, The Journal of Physical Chemistry A, 119(19), 4373-4385.

[7] Ito, A. (2013), Global modelling study of potentially bioavailable iron input from shipboard aerosol sources to the ocean, Global Biogeochem. Cycles, 27, 1–10, doi: 10.1029/2012GB004378.

[8] Jackson, R. B., et al. (2019) Methane removal and atmospheric restoration, Nature Sustainability, Vol 2, pp.s 436–438.

[9]  Chen, Xuxing, Yunpeng Li, Xiaoyang Pan, David Cortie, Xintang Huang, and Zhiguo Yi. (2016.) ‘Photocatalytic Oxidation of Methane over Silver Decorated Zinc Oxide Nanocatalysts’. Nature Communications.

See also De Richter, R. et al. (2017) Removal of non-CO2 greenhouse gases by large-scale atmospheric solar photocatalysis, Science Direct, Volume 60, Pages 68-96.