Research reveals potential of an overlooked climate change solution

Graph showing the global average monthly atmospheric methane abundance calculated from marine surface locations since 1983. Credit to NOAA
Biden encouraged other countries to join the U.S., European Union and their commitment to reduce methane emissions earlier this month. Two new Stanford-led studies could be a step in the right direction. They have created a blueprint for coordinating research on methane removal technology and modeled how it could have a significant impact on future peak temperatures.

These analyses were published in Philosophical Transactions of the Royal Society. They show that removing three years' worth of human-caused greenhouse gas emissions would decrease global surface temperature by 0.21 degrees Celsius. It would also reduce ozone levels sufficiently to prevent approximately 50,000 premature deaths each year. These findings allow for direct comparisons to carbon dioxide removal, which has been subject to much more investment and research. This could be used to help shape future national and international climate policy.

Rob Jackson, the lead author of the new research agenda paper as well as senior author on modeling study, stated that "the time is right to invest in methane elimination technologies." Jackson is the Michelle and Kevin Douglas Douglas Provostial Professor of Energy and Environment at Stanford's School of Earth, Energy & Environmental Sciences.

Methane removal: The case

Since the Industrial Revolution, the relative concentration of methane in the atmosphere has increased more than twice as fast that that of carbon dioxide. Methane can be removed from the atmosphere faster than carbon dioxide. It is 81x more potent at warming the climate in the first 20 years, and 27x more potent over a century. Methane removal improves the quality of air by reducing tropospheric oxygen, which is responsible for approximately one million premature deaths each year worldwide from respiratory diseases.

Methane is a greenhouse gas that is mainly produced by humans. Primarily, methane is emitted by agricultural sources like livestock and rice fields. Significant emissions are also caused by waste disposal and fossil fuel extract. The remaining 40% of global methane emissions comes from natural sources, such as soil microbes found in wetlands. These sources are expected to rise as the planet heats, which further complicates the picture.

Although methane removal technologies may not be easily developed, there are huge financial benefits. Each ton of methane that is removed from the atmosphere would be worth more than $2700 if carbon offsets market prices rise to $100 per ton by this century, according to most relevant assessment models.

Imagine the impacts of methane removal

To examine the potential effects of methane removal, the modeling study employs a model created by the UK Met Office. This model accounts for methane's shorter life span than carbon dioxide. However, some methane that was removed would still be there. To generalize their findings across a range of plausible future emissions pathways, the researchers devised a series of scenarios in which they could vary either the amount or the timing of methane removal.

The analysis revealed that a 40% reduction in global methane emission by 2050 would result in a temperature drop of around 0.4 degrees Celsius. A low emission scenario, where temperatures peak during the 21st Century, could see methane removal of the same size reduce the peak temperature by as much as 1 degree Celsius.

"This model allows us better understand how methane reduction alters warming on a global scale and air quality at the human scale," Sam Abernethy (a Ph.D. student working in Jackson's laboratory) said.

From research to development

It is not clear how to achieve these improvements in climate and air quality. The research agenda paper compares methane and carbon dioxide removal. It also describes various technologies for methane extraction and provides a framework to coordinate and accelerate its scaling-up. This framework will allow for more precise analysis of methane removal factors, from simulations specific to each location to possible interactions with other climate mitigation strategies.

Researchers believe that methane can be difficult to capture from the air due to its low concentration. However, a new class of crystalline materials called Zeolites, which are capable of soaking up the gas, holds the promise of providing a solution. These researchers advocate for more research on these technologies' cost and efficiency, scale and energy requirements, potential social obstacles to deployment, cobenefits, and possible negative side-effects.

Jackson stated that carbon dioxide removal has attracted billions of dollars in investments and dozens of companies have been formed. Jackson stated that similar commitments are needed for methane removal.

Continue reading Global warming will lead to ecosystems producing more methane that was first predicted.

More information: Robert B. Jackson and colleagues, Atmospheric Methane Removal: A Research Agenda, Philosophical Transactions of the Royal Society, (2021). Robert B. Jackson and colleagues, Atmospheric Methane Removal: A Research Agenda, (2021). DOI: 10.1098/rsta.2020.0454 S. Abernethy et al, Methane removal and the proportional reductions in surface temperature and ozone, Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences (2021). DOI: 10.1098/rsta.2021.0104 Journal information: Philosophical Transactions of the Royal Society A

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