Environmental Studies Professor Sikina Jinnah was a co-author on a new report from the National Academies of Sciences, Engineering, and Medicine (NASEM) that recommends a national research agenda for atmospheric methane removal technologies and assesses potential atmospheric removal tools. 

Next to carbon dioxide, methane is the second most abundant greenhouse gas contributing to global warming. Methane is short-lived in the atmosphere but is over 80 times more effective than carbon dioxide at trapping heat over a 20-year period. Together with reducing carbon dioxide emissions, large reductions in methane emissions are needed to limit warming and impacts from climate change—and yet, global methane emissions continue to rise each year.

Atmospheric methane removal would encompass human interventions to accelerate the conversion of methane in the atmosphere to a less radiatively potent form—or to physically remove methane from the atmosphere and store it elsewhere. Compared with methane mitigation or carbon dioxide removal, atmospheric methane removal is in its earliest stages of discovery, and research is limited.

Jinnah, an expert in environmental governance, was invited to join NASEM’s Committee on Atmospheric Methane Removal in May 2023 and worked with fellow committee members to produce the new report, which is intended to guide U.S. governance of and investment in research on methane removal.

“The role of methane emissions in climate change is critically important, as is the timing of this report,” Jinnah told the UC Santa Cruz news team at the time of her appointment to the committee. “In contrast to some other climate intervention strategies, where technology development has gotten out ahead of assessment of equity and justice, this committee’s report will be an early intervention and an opportunity to ensure science and justice goals are developed in tandem.”

A Research Agenda for Atmospheric Methane Removal

The committee’s final report recommends a two-phased approach to fully assess the potential for atmospheric methane removal. First, the report identifies priority foundational and systems research that should commence, with urgency, within one year.  Based on the knowledge gained through research identified in this first phase within three to five years, a second-phase assessment could then assess the viability of technologies to remove atmospheric methane at climate-relevant scales—from the perspective of technical, economic, and broader social viability.

The recommended research agenda is broken down into five key areas:

• Research to better understand atmospheric and ecosystem methane sinks and sources
• Foundational research on the technical potential of atmospheric methane removal technologies
• Research across social and policy dimensions to improve understanding of how research on atmospheric methane removal would affect and be affected by different populations. 
• Research on the social, justice, and governance dimensions of these technologies is needed to inform any potential future development and/or deployment.
• Research to understand how potential atmospheric methane removal technologies would complement, compete, or interact with other climate responses to inform their optimal use.

Assessment of Atmospheric Removal Technologies

The report assessed five atmospheric methane removal technologies with the potential to reach effectiveness at atmospheric concentrations of methane, including methane reactors, methane concentrators, surface treatments, ecosystem uptake enhancement, and atmospheric oxidation enhancement. All technologies are still firmly in the research and development stages.

At climate-relevant scales, atmospheric methane removal technologies would impact the chemical composition of the atmosphere beyond methane concentrations, the report says. The unintended consequences of the technologies may be significant, but insufficient information is available to fully assess these consequences. The research agenda and a second-phase assessment would improve understanding to inform any decision to move from knowledge discovery into more targeted investment in additional research, development, or deployment.

While the report recommends research into atmospheric methane removal technologies, it highlights that even if successfully developed, they are not a replacement for methane emissions mitigation. The report emphasizes that reduced carbon dioxide and methane emissions are critical to limit global warming. 

“Tragically, the gap between our ambitions and our actions in the climate mitigation space is massive, and has remained so for decades, ” Jinnah said. “This gap is a reflection of deeper problems in our society surrounding the way capital is accumulated and concentrated. As we continue to keep that underlying problem in the long-term crosshairs, it’s critical to explore all possible options to reduce the impacts of climate change now, especially for the world’s most vulnerable communities.

“Climate intervention technologies aren’t my preferred solution; I desperately hope we never need them. But interdisciplinary research that takes seriously the ethics and governance questions of climate intervention technologies alongside the science is necessary now to make informed decisions about the future role these technologies may play in our response to climate change.” 

This story was adapted from a press release by the National Academies of Sciences, Engineering, and Medicine.