Fracking paper overstated size of methane leak from Marcellus Shale, earning retraction

Last spring, a group of environmental scientists reported an impressive finding: Hydraulic fracturing (better known as fracking) in the Marcellus Shale region of the eastern United States was leaking enough methane to power a city twice the size of Washington, D.C. (We didn’t come up with that comparison, apt though it may be.)

Turns out that wasn’t true.

The researchers have retracted their paper, “Methane emissions from the Marcellus Shale in southwestern Pennsylvania and northern West Virginia based on airborne measurements,” which appeared in the Journal of Geophysical Research Atmospheres. The reason: Further analysis revealed a mistake in a key measurement that, once corrected, shows the leakage to be roughly half as large as they initially calculated.

And that means one of the paper’s main conclusions — that fracking was worse for climate change in the region than using coal — is more than likely wrong.

Although it’s not clear how much of an impact, if any, the article has had — beyond some traffic on Twitterand a news article that was apparently retracted yesterday — its conclusions painted a bleak picture for fracking. (The paper has not yet been cited, according to Clarivate Analytics’ Web of Science.) The authors, led by Xinrong Ren, of the University of Maryland, write:

Although recent regulations requiring capture of gas from the completion venting step of the hydraulic fracturing appear to have reduced losses, our study suggests that for a 20  year time scale, energy derived from the combustion of natural gas extracted from this region will require further controls before it can exert a net climate benefit compared to coal.

But the retraction notice tells a different story:

The article, Ren, X., et al. (2017), “Methane emissions from the Marcellus Shale in southwestern Pennsylvania and northern West Virginia based on airborne measurements,” has been retracted by the authors because of an error in wind measurements used to calculate methane emissions in the southwestern Marcellus Shale region. The error was discovered by the authors in October 2017 upon their installation of an improved, differential GPS, wind measurement system onto the aircraft used in this study. The original wind measurements led to an overestimate of methane emissions from oil and natural gas operations. A reanalysis with corrected winds reduced the total estimated emissions by about a factor of 1.7, with a correspondingly larger reduction in emissions of methane attributed to oil and natural gas in the southwestern Marcellus Shale area. This is expected to reverse a conclusion of the paper, which had asserted that leakage from oil and natural gas extraction in this region results in a climate penalty compared to the use of coal. The authors are in the process of submitting a new manuscript based on an updated analysis that will describe the process to correct the erroneous wind measurements used in the original manuscript, provide a more accurate estimate of the methane emissions, and assess the implications of the fossil fuel production from the Marcellus Shale.

The authors did not immediately respond to a request for comment.

Update, 2240 UTC, 1/22/18: Last author Russ Dickerson tells Retraction Watch:

The retraction is based on a technical correction.  Measuring winds from a moving airplane is difficult; the mean winds were good, but through rigorous testing we found that there can be a substantive error for certain aircraft headings.  The rest of the measurements and previous papers are sound.  We have replaced the instrument and corrected the prior data.  The total estimated emission rate for methane will go down, so just a “smaller effect.”