A recent study has revealed that record-high methane levels in the atmosphere may be caused by microbes, tiny organisms found in places like wetlands, cow stomachs, and agricultural fields.
These findings help explain why methane emissions have surged in recent years, creating a new concern for scientists focused on slowing global warming, The News said.
Methane, though shorter-lived in the atmosphere than carbon dioxide, has a warming effect over 80 times stronger, making it a critical factor in climate change predictions.
Sharp Rise in Methane Levels Since 2007 Linked to Biological Sources
Since 2007, methane concentrations, which had been stable, began rising by about 5 to 6 parts per billion each year. This growth rate nearly doubled in 2020, leaving scientists puzzled.
The researchers in the new study, led by Sylvia Michel from McGill University, studied methane samples from different sources worldwide, analyzing the chemical structure of methane to understand its origin.
They found that much of the methane increase is "lighter" in composition, meaning it comes from biological sources rather than fossil fuels.
Methane has different carbon signatures based on its source. Methane produced by microbes, especially in warm, low-oxygen environments like wetlands and animal stomachs, tends to be lighter, with fewer carbon-13 (C13) atoms.
In contrast, methane from fossil fuels, such as natural gas, is "heavier" and has more C13 atoms. As methane levels have risen, the scientists observed that the gas has also become lighter, strongly suggesting a rise in microbial activity.
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Warming Wetlands Could Fuel Methane "Feedback Loop," Scientists Warn
Scientists are now exploring how warming temperatures may be affecting natural methane production.
According to the Washington Post, wetlands, in particular, could be releasing more methane as they become warmer and wetter, contributing to a possible "feedback loop" in which higher temperatures lead to more methane emissions, which in turn increase temperatures further.
Researchers are concerned this process may already be underway, potentially making it harder to control methane emissions through human efforts alone.
This microbial source of methane doesn't diminish the role of human-caused emissions. Methane leaks from natural gas operations, cattle farming, and rice paddies also play a significant role, accounting for about 60% of global methane emissions.
Many countries, including the United States and members of the European Union, have pledged to reduce methane emissions by 30% by 2030 to help limit climate change. However, these promises have not yet shown significant results, as methane levels continue to climb.
Rob Jackson, a professor at Stanford University involved in the Global Methane Budget project, noted that reducing human-caused methane emissions remains essential.
Unlike natural sources like wetlands, which are difficult to control, human activities offer opportunities for direct intervention, such as preventing methane leaks in oil and gas operations.
Experts warn that while natural sources of methane are harder to manage, there are still effective ways to reduce human-related emissions. By addressing these sources, the world can potentially slow down the impact of this powerful greenhouse gas, helping to mitigate the effects of climate change.
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