New research suggests proposed climate intervention could worsen air quality while providing minimal benefits
A new study from University of Utah researchers has raised significant concerns about a proposed climate intervention that would spray hydrogen peroxide into the atmosphere to combat global warming. The research, published in Environmental Science & Technology, found that the technology would need to be deployed at an enormous scale to make any meaningful impact on methane levels, potentially leading to unintended consequences for air quality.
“Our work showed that the efficiency of the proposed technology was quite low, meaning widespread adoption of the technology would be required to make any meaningful impact on atmospheric CH4,” said lead author Alfred W. Mayhew, a postdoctoral researcher at the University’s Wilkes Center for Climate Science & Policy. “Then, our results indicate that if this technology is adopted at scale, then we start to see some negative air-quality side effects, particularly for wintertime particulate matter air pollution.”
The study focused on a patented technology that proposes using 600-meter towers to release hydrogen peroxide (H2O2) into the atmosphere during daylight hours. The chemical would then react with sunlight to produce hydroxyl radicals, which can break down methane into less harmful compounds.
Using sophisticated atmospheric modeling, the researchers examined three scenarios with varying numbers of towers and emission rates. Their findings showed that even with 50 towers operating at proposed emission rates, the technology would only reduce annual anthropogenic methane emissions by about 0.01%.
Numbers Tell a Sobering Story
To achieve a 50% reduction in human-caused methane emissions, the study calculated that approximately 352,000 towers would be needed – a scale that raises serious practical and environmental concerns. Even with enhanced emission rates, tens of thousands of towers would still be required to make a significant impact.
More troubling were the findings about air quality impacts. The research showed that large-scale deployment could lead to considerable increases in particulate matter pollution, particularly during winter months. In some regions, the 95th percentile of PM2.5 concentrations showed increases of up to 3.6 μg/m³ – a change that could push some areas out of compliance with air quality regulations.
Chemical Complexity Creates Challenges
Jessica D. Haskins, assistant professor of atmospheric sciences and co-author of the study, explained that hydroxyls are more likely to oxidize double-bonded molecules than methane, making the process inherently inefficient. The competition between methane and other atmospheric compounds for reaction with OH significantly reduces the technology’s effectiveness.
The research comes at a critical time as methane, which has 81.2 times the warming potential of carbon dioxide over a 20-year period, accounts for nearly a third of the rise in global temperatures since the Industrial Revolution. While methane only persists in the atmosphere for about nine years, its potent warming effect has made it a target for climate intervention strategies.
Cautionary Tale for Geoengineering
The study highlights broader concerns about geoengineering approaches to climate change. “There’s so many feedbacks that can go on in the climate. You change one thing and you think it’s going to do this, but it actually may do the opposite in one place versus the other,” Haskins said. “You have to be really careful and do these sorts of assessments.”
While the researchers don’t completely rule out the potential for targeted use of the technology, they emphasize that any implementation would require careful consideration of local conditions and timing. “There’s potential that future research could show that the air quality impacts of placing these towers close to methane point sources is minimal if they’re activated at certain times of the year, and far from large population centers,” Mayhew noted.
Looking Forward
The study, funded by the University of Utah’s Wilkes Center for Climate Science & Policy, represents the first comprehensive assessment of air quality impacts from atmospheric methane removal technologies. Its findings suggest that while the search for technological solutions to climate change should continue, careful evaluation of potential side effects must be a priority.
As the world grapples with the challenge of reducing greenhouse gas emissions, this research serves as a reminder that there are no easy fixes for climate change. The most effective approach, the researchers suggest, may still be reducing methane emissions at their source rather than trying to remove the gas once it’s in the atmosphere.