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Arthur T Knackerbracket [soylentnews.org] writes:

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Arthur T Knackerbracket [soylentnews.org] has found the following story [newsweek.com]:

Levels of methane—the second biggest contributor to climate change after carbon dioxide—have spiked in the atmosphere in the past decade. And a study says fracking in North America could be partly to blame.

The gas is linked to climate change, as well as ground-level ozone levels that can harm agriculture. It can also trigger a range of health problems, including chest pains, as well as reducing lung function and worsening conditions [epa.gov] such as bronchitis, emphysema and asthma.

For the new study, Howarth looked at existing research on the levels of certain carbon isotopes of atmospheric methane to find a potential source, and created an equation to investigate the link.

Methane is a compound made up of carbon and hydrogen. While methane released in the late 20th century was enriched with the carbon isotope 13C, Howarth highlights methane released in recent years features lower levels. That's because the methane in shale gas has depleted levels of the isotope when compared with conventional natural gas or fossil fuels such as coal, he explained.

This lead Howarth to conclude: "The commercialization of shale gas and oil in the 21st century has dramatically increased global methane emissions."

This could help the commitment of the Paris Agreement [unfccc.int]be met.

"If we can stop pouring methane into the atmosphere, it will dissipate. It goes away pretty quickly, compared to carbon dioxide. It's the low-hanging fruit to slow global warming."

Grant Allen, professor of atmospheric physics at the U.K.'s University of Manchester, commented: "A wide range of different methane fluxes from different source types (e.g. fossil fuels, agriculture, wildfires and wetlands) can all simultaneously explain the observed trend in methane (and carbon isotopes of methane) within the limits of uncertainty in our knowledge of their carbon-isotopic fingerprints and estimates of total methane emitted from each source type.

"Other work has also proposed a role for changing chemical sinks of methane in the atmosphere. The jury is still out on the relative importance of all of these sources in explaining methane's rise."

"The results are extremely sensitive to highly questionable assumptions regarding the isotopic composition of methane found in shale. The arguments made by previous studies that increase in methane in the atmosphere is from biogenic sources, such as release from wetlands and agriculture or burning of biomass, seem far more convincing."

"It's also the case that the study itself admits that even if the increased methane concentrations were from shale that they are not a direct result of the hydraulic fracturing process," he argued.

"For example, the USA has an aging gas transportation network, which results in significant methane leakages."

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