WASHINGTON (TheBlaze/AP) — For years, the country has had an "immense" methane leak that wasn't spotted in the southwestern U.S. until researchers were evaluating satellite data.
That result hints that U.S. Environmental Protection Agency might underestimate leaks of methane, or natural gas, significantly.
A satellite image of atmospheric methane concentrations over the continental U.S. shows a bright red hot spot over the Four Corners area of New Mexico, Colorado, Arizona and Utah. The image used data from 2003 to 2009.
Boxed in red is a major U.S. hot spot for methane emissions in this map showing how much emissions varied from average background concentrations from 2003-2009 (dark colors are lower than average; lighter colors are higher. Satellite data spotted a surprising hot spot of the potent heat-trapping gas methane over part of the American southwest. (AP/NASA, JPL-Caltech, University of Michigan)
Within that hot spot, a European satellite found atmospheric methane concentrations equivalent to emissions of about 1.3 million pounds a year. That's about 80 percent more than the EPA figured. Other ground-based studies have calculated that EPA estimates were off by 50 percent.
The methane concentration in the hot spot was more than triple the amount previously estimated by European scientists.
The new study, done by NASA and the University of Michigan, was released Thursday by the journal Geophysical Research Letters.
The amount of methane in the Four Corners — an area covering about 2,500 square miles — would trap more heat in the atmosphere than all the carbon dioxide produced yearly in Sweden. That's because methane is 86 times more potent for trapping heat in the short-term than carbon dioxide.
"It's the largest signal we can see from the satellite," said study lead author Eric Kort, a University of Michigan atmospheric scientist. "It's hard to hide from space."
There could be some areas elsewhere in the country where more methane is emitted if it is dispersed by wind, Kort said.
As for he hot spot's source, Kort said that hydraulic fracturing for natural gas should not be blamed, noting that the study's period was before fracking began in the area. However, he said in a statement that leaks in natural gas production in New Mexico's San Juan Basin, where the methane is extracted from coal, is the likely source.
"The results are indicative that emissions from established fossil fuel harvesting techniques are greater than inventoried," Kort said. "There's been so much attention on high-volume hydraulic fracturing, but we need to consider the industry as a whole."
Natural gas is 95-98 percent methane, a colorless and odorless substance, which makes leaks hard to detect without scientific instruments.
The results were so initially surprising to the scientists that they waited several years and then used ground monitors to verify what they saw from space, Kort said.
Several methane experts said the research makes sense to them and that the detected methane amount is disturbing.
"That is immense," Terry Engelder, a scientist at Pennsylvania State University, wrote in an email.