Study period predates the widespread use of hydraulic fracturing. | One small “hot spot” in the U.S. Southwest is responsible for producing the largest concentration of the greenhouse gas methane seen over the United States – more than triple the standard ground-based estimate — according to a new study of satellite data by scientists at NASA and the University of Michigan.
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 only about 2,500 square miles (6,500 square kilometers), or half the size of Connecticut.
In each of the seven years studied from 2003-2009, the area released about 0.59 million metric tons of methane into the atmosphere. This is almost 3.5 times the estimate for the same area in the European Union’s widely used Emissions Database for Global Atmospheric Research.
In the study published online Thursday, October 9th in the journal Geophysical Research Letters, researchers used observations made by the European Space Agency’s Scanning Imaging Absorption Spectrometer for Atmospheric Chartography (SCIAMACHY) instrument. SCIAMACHY measured greenhouse gases from 2002 to 2012. The atmospheric hot spot persisted throughout the study period. A ground station in the Total Carbon Column Observing Network, operated by the Department of Energy’s Los Alamos National Laboratory, provided independent validation of the measurement.
To calculate the emissions rate that would be required to produce the observed concentration of methane in the air, the authors performed high-resolution regional simulations using a chemical transport model, which simulates how weather moves and changes airborne chemical compounds.
Research scientist Christian Frankenberg of NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, California, first noticed the Four Corners signal years ago in SCIAMACHY data.
“We didn’t focus on it because we weren’t sure if it was a true signal or an instrument error,” Frankenberg said.
The study’s lead author, Eric Kort of the University of Michigan, Ann Arbor, noted the study period predates the widespread use of hydraulic fracturing, known as fracking, near the hot spot. This indicates the methane emissions should not be attributed to fracking but instead to leaks in natural gas production and processing equipment in New Mexico’s San Juan Basin, which is the most active coalbed methane production area in the country.
Natural gas is 95-98 percent methane. Methane is colorless and odorless, making leaks hard to detect without scientific instruments.
“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.”
Coalbed methane is gas that lines pores and cracks within coal. In underground coal mines, it is a deadly hazard that causes fatal explosions almost every year as it seeps out of the rock. 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, coalbed methane supplied about 8 percent of all natural gas in the United States.
Frankenberg noted that the study demonstrates the unique role space-based measurements can play in monitoring greenhouse gases.
“Satellite data cannot be as accurate as ground-based estimates, but from space, there are no hiding places,” Frankenberg said.
Here is the study: http://onlinelibrary.wiley.com/doi/10.1002/2014GL061503/abstract
Four corners: The largest US methane anomaly viewed from space
Methane (CH4) is a potent greenhouse gas and ozone precursor. Quantifying methane emissions is critical for projecting and mitigating changes to climate and air quality. Here we present CH4 observations made from space combined with Earth-based remote sensing column measurements. Results indicate the largest anomalous CH4 levels viewable from space over the conterminous U.S. are located at the Four Corners region in the Southwest U.S. Emissions exceeding inventory estimates, totaling 0.59 Tg CH4/yr [0.50–0.67; 2σ], are necessary to bring high-resolution simulations and observations into agreement. This underestimated source approaches 10% of the EPA estimate of total U.S. CH4 emissions from natural gas. The persistence of this CH4 signal from 2003 onward indicates that the source is likely from established gas, coal, and coalbed methane mining and processing. This work demonstrates that space-based observations can identify anomalous CH4 emission source regions and quantify their emissions with the use of a transport model.
It isn’t hard to see why this hotspot appears. An examination of Google Earth right over the hotspot reveals a plethora of well sites:
A closeup view leaves no question:
It seems to be little more than a matter of leakage, something easily dealt with with a natural gas leak sniffer used by many utility companies and some simple preventative maintenance.
From the Four Corners Oil and Gas Conference website:
The Four Corners area, which is made up of Northwestern New Mexico, Southwestern Colorado, Northeastern Arizona and Southeastern Utah, contains the San Juan Basin which is one of the premier natural gas deposits in the United States. The San Juan Basin has contributed more than eight percent of the nation’s current natural gas supply. Our area has produced more than 370 million barrels of oil and nearly 38 trillion cubic feet of natural gas. There are currently more than 20,000 producing wells with a prediction of up to 5,000 additional wells targeting natural gas in the upcoming years. The United States Geological Survey projects possible undiscovered resources at more than 50 trillion cubic feet of natural gas, 148 million barrels of natural gas liquids and between 7 and 35 million barrels of oil.
I suggest that a little bit of self-policing applied as a key topic in the next Four Corners Oil and Gas Conference would go a long way towards preventing yet another regulatory hammer coming down from the EPA.
Note that the other “hotspot” for methane emissions is near Bakersfield, California, with another concentration of wells, in a state that has greater regulatory control over emissions: