Research reveals potential for neglected solution to climate change

Earlier this month, President Biden urged other countries to join the United States and the European Union in a commitment to reduce methane emissions. Two new studies led by Stanford could help lead the way by laying out a plan to coordinate research on methane removal technologies and modeling how the approach could have a disproportionate effect on reducing future peak temperatures.

The analyzes, published on September 27 in Philosophical Transactions of the Royal Society A, reveal that removing about three years of human-made emissions of the potent greenhouse gas would reduce global surface temperatures by about 0.21 degrees Celsius while reducing ozone levels enough to avoid about 50,000 premature deaths per year. The findings open the door to direct comparisons with removing carbon dioxide – an approach that has received much more research and investment – and could help shape national and international climate policies in the future. to come up.

“Now is the time to invest in methane removal technologies,” said Rob Jackson, lead author of the new research program paper and lead author of the modeling study. Jackson is the Michelle and Kevin Douglas Senior Professor of Energy and Environment at the Stanford School of Earth, Energy and Environmental Sciences.

The case of methane removal

The relative concentration of methane has increased more than twice as fast as that of carbon dioxide since the start of the industrial revolution. Removing methane from the atmosphere could reduce temperatures even faster than removing carbon dioxide alone, as methane is 81 times more potent in terms of global warming in the first 20 years after its release, and about 27 times more powerful over a century. Removing methane also improves air quality by lowering the concentration of ground-level ozone, to which exposure causes approximately one million premature deaths worldwide due to respiratory illnesses.

Unlike carbon dioxide, the majority of methane emissions are of human origin. The main culprits are agricultural sources such as livestock, which emit methane in their breath and manure, and paddy fields, which emit methane when flooded. Waste disposal and the extraction of fossil fuels also contribute substantial emissions. Natural sources of methane, including soil microbes in wetlands, account for the remaining 40 percent of global methane emissions. They further complicate the picture because some of them, like thawing permafrost, are expected to increase as the planet warms.

While developing methane removal technologies is not easy, the potential financial rewards are significant. If market prices for carbon offsets reach $ 100 or more per tonne during this century, as most relevant valuation models predict, then each tonne of methane extracted from the atmosphere could be worth more than 2 $ 700.

Consider the impacts of methane elimination

The modeling study uses a new model developed by the UK’s National Weather Service (known as the UK Met Office) to examine the potential impacts of removing methane while taking into account its longer lifespan. shorter than carbon dioxide – a key factor as some of the methane removed would have been gone anyway. The researchers created a set of scenarios by varying either the amount withdrawn or the time of elimination to generalize their results over a wide range of realistic future emission trajectories.

In a high emissions scenario, the analysis showed that a 40% reduction in global methane emissions by 2050 would result in a temperature reduction of about 0.4 degrees Celsius by 2050. In a low emission scenario where temperature peaks in the 21st century, removing methane of the same magnitude could reduce the temperature peak to 1 degree Celsius.

“This new model allows us to better understand how the removal of methane alters global warming and human-scale air quality,” said Sam Abernethy, lead author of the modeling study. and co-author of the research program. applied physics student who works in Jackson’s lab.

From research to development

The way forward to achieve these improvements in climate and air quality remains uncertain. To highlight this, the research program document compares and contrasts aspects of carbon dioxide and methane removal, describes a range of technologies for methane removal, and describes a framework for coordinating and accelerating its removal. intensification. The framework would help facilitate a more precise analysis of methane removal factors, ranging from location-specific simulations to potential interactions with other climate change mitigation approaches.

Methane is difficult to capture in the air due to its low concentration, but burgeoning technologies, such as a class of crystalline materials called zeolites capable of absorbing gas, hold the promise of a solution, according to Researchers. They call for increased research into the cost, efficiency, scale and energy needs of these technologies, potential social barriers to deployment, co-benefits and possible negative by-products.

“The elimination of carbon dioxide has received billions of dollars in investment, with the formation of dozens of companies,” Jackson said. “We need similar commitments for the phase-out of methane.”