Microbes have emerged as major source of methane emissions

Methane is a central player in the fight against climate change. While exploring sources of methane and the role of microbes as a potential solution, a team of researchers discovered something surprising.

The experts identified a miniature but potent contributor to the worsening global warming crisis — and it’s not our industrial activities.

In a world-first, the study has revealed that microbes in the environment play a significant role in the ongoing surge of global methane emissions. This unexpected discovery may help guide more effective mitigation strategies.

Methane emissions from microbes

Sylvia Michel is a senior research assistant at the Institute of Arctic and Alpine Research(INSTAAR) and a doctoral student in the Department of Atmospheric and Oceanic Sciences at CU Boulder.

“Understanding where the methane is coming from helps us guide effective mitigation strategies. We need to know more about those emissions to understand what kind of climate future to expect,” said Michel.

Methane takes the spotlight in these findings for good reason. It’s a potent greenhouse gas that is responsible for a third of the planet’s post-industrialization warming.

Despite a lower atmospheric presence than carbon dioxide over a 100-year period, methane has 30 times the heat-trapping power. This makes it a formidable foe in the climate change battle.

“Methane concentrations in the air have almost tripled since the 1700s,” noted study co-author Professor Jianghanyang (Ben) Li.

Reducing methane emissions

Interestingly, this harmful methane gas degrades within a decade, unlike CO2, which lingers in the atmosphere for millennia.

Addressing methane emissions provides immediate and potent effects in slowing down global warming, making it a “low-hanging fruit,”.as Li put it.

While research suggests microbes surpassed fossil fuels in methane emissions, it doesn’t diminish the importance of reducing fossil fuel consumption for climate change mitigation.

The team further recommends cutting down on food waste and consuming less red meat as effective measures in reducing individual methane footprints.

Understanding the perpetrators

Historically, scientists identified fossil fuel production as responsible for 30% of global methane emissions. Microbial sources including wetlands, cattle, and landfills contribute to over half of these emissions.

Archaea, a soil-dwelling microorganism and resident of cow intestines, produces methane as a byproduct of organic matter decomposition.

The research team collaborated with Boulder’s Global Monitoring Laboratory at the National Oceanic and Atmospheric Administration.

By analyzing air samples from around the world, the team identified methane sources by examining the sample’s carbon atoms and isotopes. The lab has conducted methanol isotope measurements since 1998.

Microbes’ contribution to methane emissions

The team used computer simulations to model different emissions scenarios. They found that between 2020 and 2022, microbial sources drove a staggering increase in atmospheric methane.

While microbes contributed significantly to methane emissions since 2007, their contribution skyrocketed to over 90% in 2020.

“Some prior studies have suggested that human activities, especially fossil fuels, were the primary source of methane growth in recent years,” said Xin (Lindsay) Lan, a scientist at the Cooperative Institute for Research in Environmental Sciences.

“These studies failed to look at the isotope profile of methane, which could lead to a different conclusion and an incomplete picture of global methane emissions.”

True origins of methane emissions

It remains to be seen whether increased methane emissions from microbes originated primarily from natural sources like wetlands or from human-driven activities such as landfills, livestock farming, and agriculture.

Pinpointing the exact origins of the emissions is crucial for developing tailored strategies to combat methane release.

The research team will use advanced tools and methodologies to identify the precise source of this methane. This will provide clearer insights into how human activity and natural processes contribute to the global methane surge.

“In a warming world, it wouldn’t be surprising if any of these sources emitted more methane,” said Michel.

“Consequently, more methane could stay in the atmosphere to accelerate global warming. So we need to address the climate crisis, and that really means addressing CO2 emissions.”

The study is published in the journal Proceedings of the National Academy of Sciences.

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