Another major study points to questions about whether natural gas offers greenhouse benefits

February 9, 2012 by Ken Ward Jr.

There’s a major new study out this week that provides more evidence to support questions about whether natural gas is really better than coal in terms of reducing greenhouse gas emissions and dealing with the climate crisis.

I first saw a report of the study on Joe Romm’s excellent Climate Progress blog. Joe is calling this a “bombshell study,” and he explains:

How much methane leaks during the entire lifecycle of unconventional gas has emerged as a key question in the fracking debate.  Natural gas is mostly methane (CH4).  And methane is a far more potent greenhouse gas than (CO2), which is released when any hydrocarbon, like natural gas, is burned.

Even without a high-leakage rate for shale gas, we know that “Absent a Serious Price for Global Warming Pollution, Natural Gas Is A Bridge To Nowhere.”

But the leakage rate does matter.  A major 2011 study by Tom Wigley of the Center for Atmospheric Research (NCAR) concluded:

The most important result, however, in accord with the above authors, is that, unless leakage rates for new methane can be kept below 2%, substituting gas for coal is not an effective means for reducing the magnitude of future climate change.

Now, as the journal Nature reports, we finally have some actual air sampling measurements, and they appear to confirm the higher estimates put forward by Cornell professor Robert Howarth:

When US government scientists began sampling the air from a tower north of Denver, Colorado, they expected urban smog — but not strong whiffs of what looked like natural gas. They eventually linked the mysterious pollution to a nearby natural-gas field, and their investigation has now produced the first hard evidence that the cleanest-burning fossil fuel might not be much better than coal when it comes to climate change.

Led by researchers at the National Oceanic and Atmospheric Administration (NOAA) and the University of Colorado, Boulder, the study estimates that natural-gas producers in an area known as the Denver-Julesburg Basin are losing about 4% of their gas to the atmosphere — not including additional losses in the pipeline and distribution system. This is more than double the official inventory, but roughly in line with estimates made in 2011 that have been challenged by industry. And because methane is some 25 times more efficient than carbon dioxide at trapping heat in the atmosphere, releases of that magnitude could effectively offset the environmental edge that natural gas is said to enjoy over other fossil fuels.

Methane is 25 times  more efficient than CO2 trapping heat over 100 year — but it is 100 times more efficient than CO2 trapping heat over two decades.


“If we want natural gas to be the cleanest fossil fuel source, methane emissions have to be reduced,” says Gabrielle Pétron, an atmospheric scientist at NOAA and at the University of Colorado in Boulder, and first author on the study, currently in press at the Journal of Geophysical Research. Emissions will vary depending on the site, but Pétron sees no reason to think that this particular basin is unique. “I think we seriously need to look at natural-gas operations on the national scale.”

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