Science is an interactive process made rigorous through replication of results and critical examination of data and methodology. A methane leakage paper authored by scientists at NOAA and the University of Colorado and now a critical paper that refutes its conclusions provide are the scientific process at work.
On Friday, October 12th, the Journal of Geophysical Research published a peer-reviewed comment by Michael Levi of the Council on Foreign Relations that offers strong scientific criticism of the NOAA/University of Colorado paper. blogs.cfr.org/levi/. Please also see discussion at:
In great technical detail (his paper is more formulas than words), Mr. Levi describes errors that in his judgment the NOAA/University of Colorado team made that led to erroneous conclusions of methane leakage rates in the 2.3% to 7.7% range. When corrected for the errors that Levi identifies, Mr. Levi calculates that the raw data measured by the NOAA/University of Colorado team is consistent with leakage rates of 1% to 2%.
As Mr. Levi notes, leakage rates of 1% to 2% is the most commonly accepted current range of methane leakage rates arrived at by measuring, estimating, and extrapolating leakages in the various parts of the process. The NOAA was limited to one place in one time period--on a non-shale development area of Colorado in 2008. But its conclusions stood in sharp conflict with the bulk of evidence on leakage rates and so is particularly important to understand, confirm or refute.
On twitter, Levi said his paper had been accepted for publication in April of 2012 and had been available to the NOAA/University of Colorado team for 7 months so far without their promise response to it forthcoming. When it arrives, assuming it will, the response will be important and examined closely.
Few things are more important to the global future of natural gas than having a good understanding of methane leakage rates and taking measures to reduce it further. On that score, the recent EPA natural gas air rules will cut further current leakage rates, and that is good news for natural gas and the environment.