E. Siberian Shelf Methane Releases Approaching 20% Of All US Natural Gas Leaks: Bottom Temps Up 0.9F
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Shakhova has spent the past decade compiling data on the East Siberia Arctic Shelf through research cruises and flyovers of the region. She published initial results in 2010, which showed that methane has been escaping at hot spots where vents have formed from a combination of geothermal heat as well as warmer river water flowing into the region. Those results showed that 7 teragrams of methane is bubbling to the surface annually. That's roughly the equivalent of 10 percent of the methane emissions from U.S. oil and natural gas production and transmission in 2012.
The new research refined those results, showing the amount of methane reaching the surface is more than double those previous estimates. In all, Shakhova and her colleagues estimate that 17 teragrams are escaping each year, though the new study says the estimates are likely on the conservative end. Shakhova said those totals are on par with emissions from the Arctic tundra.
One of the reasons for the revised estimates was more rigorous measurements using an unmanned underwater vehicle with advanced sonar technology. It provided a clearer image of the seafloor and the amount of methane escaping from vents.
Shakhova's research also shows that annual bottom water temperatures have increased 0.9°F over the past 14 years while summer temperatures have increased 1.8°F over the same period. That’s due in large part to increased runoff from rivers, which generally have warmer water than the Siberian Sea. Other research has pegged that increase at 7 percent from 1936 to 1999.
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http://www.climatecentral.org/news/storms-warming-mean-more-arctic-methane-being-released-16775