February 21st, 2020 by  

Methane emissions are much higher than reported, according to a new analysis by researchers at the University of Rochester. After studying atmospheric samples that predate the start of the Industrial Revolution — taken from ice cores obtained in the Arctic — the research team was able to distinguish between methane emissions that arise from normal biological activity, such as decaying vegetation, and methane derived from anthropogenic sources related to human activity. The distinction is made possible by carbon-14 detection. In older samples, the isotope has disappeared, while in later times it is still present.

The research shows an increase in methane emissions beginning in 1870. The scientists determined that levels of naturally released fossil methane are about 10 times lower than previous research reported. Given the total fossil emissions measured in the atmosphere today, the researchers claim anthropogenic methane is 25 to 40% higher than expected. If it’s not coming from biological sources, it must be coming from fossil fuel extraction and combustion, they say.

What difference does any of this make? Methane, which is 90% of natural gas, is the second leading cause of our Earth getting hotter. It is a more powerful greenhouse gas but remains in the atmosphere for only about 9 years, whereas carbon dioxide remains in the atmosphere for 100 years or more. If humans could greatly reduce global methane emissions, the effect could be to buy more time to address carbon dioxide emissions, according to Science Daily. The study was published on February 19 in the journal Nature.

“If we stopped emitting all carbon dioxide today, high carbon dioxide levels in the atmosphere would still persist for a long time,” says Benjamin Hmiel, the lead author of the study. “Methane is important to study because if we make changes to our current methane emissions, it’s going to reflect more quickly. Placing stricter methane emission regulations on the fossil fuel industry will have the potential to reduce future global warming to a larger extent than previously thought,” Hmiel says.

“As a scientific community we’ve been struggling to understand exactly how much methane we as humans are emitting into the atmosphere,” says Vasilli Petrenko, a coauthor of the study. “We know that the fossil fuel component is one of our biggest component emissions, but it has been challenging to pin that down because in today’s atmosphere, the natural and anthropogenic components of the fossil emissions look the same, isotopically.” Hmiel adds, “What we’ve previously categorized as n

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