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 natural methane emission must be anthropogenic sources, the most likely being fossil fuel use and extraction.”
The study has important implications for the environment. If anthropogenic methane emissions make up a larger part of the total, reducing emissions from human activities like fossil fuel extraction and use will have a greater impact on curbing future global warming than scientists previously thought. “I don’t want to get too hopeless on this because my data does have a positive implication,” Hmiel says. “Most of the methane emissions are anthropogenic, so we have more control. If we can reduce our emissions, it’s going to have more of an impact.”
Not Everyone Agrees
The Washington Post reached out to other scientists and found that not everyone agrees with the assessment made by the University of Rochester research team. The Hmiel group claims global methane emissions in the 1700s were 1 to 5 million tons a year. Today, they are 45 million tons annually and rising — fast. See this chart prepared by NOAA.
Hmiel and his colleagues argue that the increase is due to the use of natural gas. Daniel Jacob, a Harvard atmospheric scientist and methane expert not involved in the work, told The Washington Post the study represents an “important result, because the current estimates for the methane geological source were widely considered too high by atmospheric modelers such as myself.” However, he adds, “I totally disagree with this inference.” If natural sources of fossil methane are smaller, he argued, that simply means total emissions are smaller — not that we should bump up emissions from another source in their place.
Stefan Schwietzke, a researcher with the Environmental Defense Fund, believes the Rochester researchers have significantly undercounted biological sources of methane. He notes a recent study published last month in the journal Science Advances found methane emissions from just one sector of the Arctic ocean are 3 million tons per year.
He adds that methane emissions just from beneath the Caspian Sea are thought to be large enough to account for much of the global total. “The major question is now how to reconcile [the new study] with recent regional measurements,” Schwietzke says.
Making Methane Plumes Visible
In December, investigators for The New York Times used infrared photography to make methane leaks in the Permian Basin in Texas visible. The current administration plans to roll back regulations requiring industry to reduce methane leaks from its operations, a move that the EPA itself says will allow enough methane to escape to power up to 1 million American homes.
That’s a lot of methane, but the industry claims it is too expensive and too complicated to monitor methane emissions, even though the NY Times was able to do it with an infrared camera. We cannot reproduce the proprietary images gathered by the the NY Times, but you can see them on its website. They are quite disturbing.
Tim Doty, a former senior official at the Texas Commission on Environmental Quality who is trained in infrared leak detection, examined and helped analyze the film images gather by the Times photographer. “That’s a crazy amount of emissions,” he said. “It takes a little bit of investigative work, but with an infrared camera, you can see it.”
Robert Howarth, an earth system scientist at Cornell University, tells The New York Times, “It’s increasingly clear that fossil fuel production has dramatically increased global methane emissions.” He is the author of a study that estimates North American shale gas production may be responsible for about a third of the global increase in methane emissions over the past decade, a finding hotly denied by the shale gas industry.
Here’s what we know. Methane is a powerful greenhouse gas. Reducing the amount that escapes into the atmosphere every year would help control global heating. Industry is unable or unwilling to identify and remediate methane leaks, even if that means the environment becomes less able to support human life.
The economic system currently in effect in most developed countries places the burden on society to clean up any emissions attributable to commercial and industrial activity. It’s a “heads we win, tails you lose” situation that threatens the health and safety of every living thing on planet Earth.
Whether anthropogenic sources are responsible for a tenth, a third, half, or two-thirds of global methane emissions is not the point. The point is that any methane emissions lead to negative consequences for the environment and should be eliminated to the extent possible. To do otherwise is irrational and irresponsible.
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