A cloud of methane gas about the size of Delaware was detected over the Four Corners area of the American southwest years ago. But people didn’t take it seriously, because (believe it or not) – it was so big that they thought it was an instrument error.

The Four Corners area (red) is the 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).
Image Credit: NASA/JPL-Caltech/University of Michigan

“We didn’t focus on it because we weren’t sure if it was a true signal or an instrument error,” said Christian Frankenberg, a research scientist at NASA’s Jet Propulsion Laboratories in Pasadena, California, in an article on NASA’s news website.

Methane is a greenhouse gas, like CO2 – except it’s much more powerful than that. Pound for pound, its impact is 20 times greater than CO2 over a 100-year period. Globally, 60% of all methane emissions stem from human activity, and in the US, the figure is even larger – so we’re dealing with the effects of human activity here – most notably, natural gas. Natural gas is 95-98 percent methane.

“The results are indicative that emissions from established fossil fuel harvesting techniques are greater than inventoried,” said Eric Kort of the University of Michigan, Ann Arbor, the study’s author. “There’s been so much attention on high-volume hydraulic fracturing, but we need to consider the industry as a whole.”

Coalbed methane is gas that lines pores and cracks within coal. In underground coal mines, it is an extremely dangerous hazard that causes fatal explosions almost every year as it seeps out of the rock. Following the energy crisis in the US in the 1970s, techniques were developed to extract the methane from the coal and use it as fuel. Today, just under 10 percent of all the natural gas in the US comes from coalbed methane.

The hot spot, near the Four Corners intersection of Arizona, Colorado, New Mexico and Utah, covers only about 2,500 square miles (6,500 square kilometers), or half the size of Connecticut. It’s still not clear what the long term effects of this hotspot will be, but it’s clear that it will be associated with increased climate change and global warming. This find highlights the importance of greenhouse gas monitoring from outer space – the fact that this was thought for years to be an instrument defect is quite worrying.

“Satellite data cannot be as accurate as ground-based estimates, but from space, there are no hiding places,” said Christian Frankenberg of NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, California, who first noticed the Four Corners signal years ago in SCIAMACHY data. “[initiallt] we didn’t focus on it because we weren’t sure if it was a true signal or an instrument error,” Frankenberg said.