NASA Flew Gas Detectors Above California, Found ‘Super Emitters’https://www.bloomberg.com/amp/news/articles/2019-11-06/nasa-flew-gas-detectors-above-california-found-super-emitters
Over the course of three years, NASA flew a plane carrying gas-imaging equipment above California and made a discovery that surprised even the state’s own environmental agencies: A handful of operations are responsible for the vast majority of methane emissions.
In a report published in
Nature on Wednesday, scientists estimated that 10% of the places releasing methane -- including landfills, natural gas facilities and dairy farms -- are responsible for more than half of the state’s total emissions. And a fraction of the 272,000 sources surveyed -- just 0.2% -- account for as much as 46%.
For example, of the 270 surveyed landfills, only 30 were observed to emit large plumes of methane. However, those 30 were responsible for 40% of the total point-source emissions detected during the survey.
NASA’s aircraft made dozens of flights across 10,000 square miles from 2016 through 2018. Landfills accounted for 41% of the source emissions it identified, manure management 26% and oil and gas operations 26%.
The team identified more than 550 individual point sources emitting plumes of highly concentrated methane. Ten percent of these sources, considered super-emitters, contributed the majority of the emissions detected. The team estimates that statewide, super-emitters are responsible for about a third of California's total methane budget.
The results are already effecting change. The survey revealed four incidents of leaking natural gas distribution lines and one leaking liquefied natural gas storage tank, which operators confirmed and repaired.
Riley M. Duren et al.
California's methane super-emitters,
Nature (2019)
