(CN) – For two years a NASA aircraft scoured from the sky in search of deadly gas, but the mission was not over an alien planet: it searched for sources of methane in California.
The results of a statewide survey show a small number of industrial facilities are responsible for about a third of all methane put into the atmosphere above California. Those include landfills and oil wells according to the new study by NASA’s Jet Propulsion Laboratory published Wednesday in the journal Nature.
Methane concentrations in Earth’s atmosphere have increased exponentially over the last 300 years thanks in large part to ongoing fossil fuel use. Livestock and other agricultural industries and the breakdown of organic waste in landfills also factor into the mix.
In their study, NASA scientists monitored 300,000 facilities and infrastructure components across California over a two-year period. Thanks to a plane equipped with Airborne Visible InfraRed Imaging Spectrometer – Next Generation (AVIRIS-NG) the survey measured methane outputs, including small plumes that typically go undetected.
The team found more than 550 locations emitted high plumes of concentrated methane. While 270 landfills were surveyed, there were 30 outliers that accounted for 40% of the total point-source emissions detected during the survey.
According to the data, the biggest offenders were landfills, which produced 41% of the methane, followed by the oil and gas sector and dairy farms at 26% each.
That type of information can go a long way to help reduce possible leaks and malfunctions within those sites gas-capture systems.
Lead scientist on the study, Riley Duren with NASA's Jet Propulsion Laboratory said, “These findings illustrate the importance of monitoring point sources across multiple sectors [of the economy] and broad regions, both for improved understanding of methane budgets and to support emission mitigation efforts.”
Results from the study were given to facility operators so they can improve their methane-leak detection systems and results will be used to help state agencies curb output by prioritizing how they too can cutback emissions.
Researchers say this was the first attempt to estimate emissions for individual methane sources spread over an extensive area in a two-year window. The survey also excluded small natural gas leaks from millions of homes, because their emissions are below the detection levels of the method that was followed.
The survey was conducted by NASA, California Air Resources Board and the California Energy Commission. The final report will published in the fall.
Read the Top 8
Sign up for the Top 8, a roundup of the day's top stories delivered directly to your inbox Monday through Friday.