Climate Game-Changer: Fossil Fuels Aren’t Behind Surging Methane Emissions

Methane or Ammonium Molecules — A new study from CU Boulder reveals that microbes, rather than fossil fuels, have been the main driver of the recent surge in methane emissions globally. While fossil fuel reduction remains essential for climate change mitigation, cutting food waste and reducing red meat consumption can also help lower methane emissions.

Microbes are now the primary driver of methane emissions, according to CU Boulder researchers. Mitigating fossil fuel use and other human-related activities is still key to tackling climate change.

According to a new detailed analysis recently published in the Proceedings of the National Academy of Sciences by researchers from CU Boulder and their collaborators, the recent global surge in methane emissions is being driven by microbes in the environment rather than by fossil fuels.

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

Methane is a potent greenhouse gas responsible for about a third of the planet’s warming since industrialization. Although the atmosphere contains less methane than carbon dioxide, methane traps about 30 times more heat than carbon dioxide over a 100-year time frame, making it a critical target for addressing climate change.

“Methane concentrations in the air have almost tripled since the 1700s,” said co-author Jianghanyang (Ben) Li, an assistant professor in the Department of Atmospheric and Oceanic Sciences and INSTAAR.

But unlike CO2, which can stay in the atmosphere for thousands of years, methane degrades within a decade. As a result, addressing methane emissions can have an immediate and powerful impact in slowing the rate of warming, making it a “low-hanging fruit,” Li said.

While the finding suggests microbes have been emitting more methane than fossil fuels in recent years, reducing fossil fuel consumption remains key to addressing climate change, the team said. Cutting down food waste and consuming less red meat can also help lower one’s methane footprint.

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Previous research suggests fossil fuel production is responsible for about 30% of global methane emissions.

But microbial sources—such as wetlands, cattle, and landfills— are an even more significant source of methane, accounting for more than half of global emissions. Archaea, a type of microorganism living in soil and the guts of cows, produce methane as a byproduct of breaking down organic matter.

Michel and Li have been working with Boulder’s Global Monitoring Laboratory (GML) at the National Oceanic and Atmospheric Administration (DOI: 10.1073/pnas.2411212121