Four Corners methane hotspot points to coal-related sources

October 28, 2014 by Nancy Ambrosiano, Oak Ridge National Laboratory
Four Corners methane hotspot points to coal-related sources
Los Alamos National Laboratory measurement instruments were placed in the field for analysis of Four Corners area power plant emissions.

A large, persistent methane hot spot has existed over the Four Corners area of the U.S. Southwest for almost a decade, confirmed by remote regional-scale ground measurements of the gas by DOE's Los Alamos National Laboratory.

"A detailed analysis indicates that in the region are actually three times larger than reported by EPA. Our analysis demonstrates that current EPA inventories are missing huge methane sources in the region," said Manvendra Dubey, a Los Alamos National Laboratory scientist on the project. "We attribute this hot spot to fugitive leaks from coal-bed methane that actually preceded recent concerns about potential emissions from fracking," Dubey said.

A team of LANL, NASA and University of Michigan scientists reported these results in the journal Geophysical Research Letters. Methane is very efficient at trapping heat in the atmosphere and, like carbon dioxide, it contributes to global warming.

The hot spot, near the Four Corners intersection of Arizona, Colorado, New Mexico and Utah, covers about 2,500 square miles (6,500 square kilometers), or half the size of Connecticut. The Los Alamos measurement ground site was located near the community of Waterflow at the New Mexico Environment Department's San Juan monitoring site, close to two coal-fired power plants. This is an extensive coal-mining region with historically large coal-bed methane production.

Los Alamos' remote sensing observations, taken continuously through 2011 and 2012, showed large morning increases of methane. Interestingly, a European satellite had measured methane in that area daily for seven years, from 2003-2009. "Our persistently measured increases in methane, seen over 70 percent of the time, verified that the methane hot spot observed over that same Four Corners area was real," said Dubey the lead LANL scientist on the team. "It is clear that current EPA inventories are missing huge methane sources in the region," Dubey said.

"We were excited to share the results with our collaborators and we followed up with high-resolution regional atmospheric modeling of the current EPA reported methane emissions for the region. When we compared the simulated methane with both our ground and satellite observations we found that they were a factor of three too low, a fairly remarkable result," he said.

What was surprising, Dubey noted, is that the region had almost no hydraulic fracturing of oil or gas in the 2003-2009 period and the satellite still saw the large methane hot spot. Coal-bed methane is a gas that lines the myriad pores and cracks within a seam of coal. In underground coal mines, the trapped methane is a deadly hazard that causes sometimes-fatal explosions almost every year as it seeps out of the rock. This coal-bed methane, leaking progressively from the sites, may be the source of the newly measured material.

After the U.S. energy crisis of the 1970s, techniques were invented to extract the methane from the coal and use it for fuel. By 2012, coal-bed methane supplied about 8 percent of all natural gas in the United States. "Our finding clearly shows that one needs to look at the fossil mining industry as a whole when it comes to fugitive leaks, and that research on verification of reported leaks is critically needed," Dubey said.

"In light of the expansion of hydraulic fracturing in the Farmington, New Mexico region it is important that we continue extensive monitoring with the state environment department to assure we are attributing and managing the overall methane emissions responsibly," he continued.

Methane is a less climate-damaging energy source than coal, emitting half as much carbon dioxide as coal per unit energy produced. However, it is 25 times more potent a greenhouse gas than carbon dioxide so keeping fugitive leaks is crucial to harvest its potential as a bridge fuel, according to the science team.

"As the quest to understand emissions continues we must also correct for the missing coal-related methane sources and other biogenic sources that include cattle, landfills, and wetlands," Dubey noted. "Regional scale measurements from ground and space coupled to modeling are critical to achieve this for responsible energy and environmental policy – and we have much more research to do."

Explore further: Space-based methane maps find largest US signal in Southwest

Related Stories

Space-based methane maps find largest US signal in Southwest

October 9, 2014

An unexpectedly high amount of the climate-changing gas methane, the main component of natural gas, is escaping from the Four Corners region in the U.S. Southwest, according to a new study by the University of Michigan and ...

Figuring out methane's role in the climate puzzle

July 9, 2014

The U.S. may be on the verge of an economy driven by methane, the primary component of natural gas, which burns cleaner than coal and is undergoing a production boom. It has poised the country as a top fuel producer globally, ...

Control methane now, greenhouse gas expert warns

May 14, 2014

(Phys.org) —As the shale gas boom continues, the atmosphere receives more methane, adding to Earth's greenhouse gas problem. A Cornell ecology professor fears that we may not be many years away from an environmental tipping ...

Recommended for you

In China, a link between happiness and air quality

January 21, 2019

For many years, China has been struggling to tackle high pollution levels that are crippling its major cities. Indeed, a recent study by researchers at Chinese Hong Kong University has found that air pollution in the country ...

3 comments

Adjust slider to filter visible comments by rank

Display comments: newest first

Science Officer
1 / 5 (4) Oct 28, 2014
Wow, we've had all this unknown methane leakage into our atmosphere for all there years, and there still hasn't been any significant global warming for over 17 years. Those greenhouse gases must be really over-rated.
MandoZink
5 / 5 (4) Oct 28, 2014
Wow, we've had all this unknown methane leakage into our atmosphere for all there years, and there still hasn't been any significant global warming for over 17 years. Those greenhouse gases must be really over-rated.

I, too, am greatly confused when something on a massive scale is not affected by a comparatively miniscule phenomenon.
zz5555
5 / 5 (4) Oct 28, 2014
Wow, we've had all this unknown methane leakage into our atmosphere for all there years, and there still hasn't been any significant global warming for over 17 years. Those greenhouse gases must be really over-rated.


Keep in mind that climate change/global warming is caused by changes in the climate drivers. So if the methane leakage has been there all these years, then it can't, by definition, cause climate change.

Also, as you correctly imply, although the surface temperatures of the earth haven't seen statistically significant warming for the past 18 years (although 19 and longer do see statistically significant warming, the earth has continued to see warming for the last 18, 17, 16, 15, etc. years. And when the oceans are considered, there has been warming for every year. Interesting how science always triumphs over political rhetoric, isn't it? ;)

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.