As was widely reported this week, a new study has just come out concluding that, compared to coal, shale gas fracking is anywhere from just as bad to much worse in terms of greenhouse gas emissions. Despite the holy-grail of peer-revision, there appear to be some very obvious methodological problems and reliance on very poor data (which the researchers have admitted, and wish they had access to better information).
Here is a piece of a review from Matt Ridley, entitled “Black Propaganda.” (Read the whole thing):
So, in other words, shale gas has greater global warming potential than coal only if you rely on lousy data, misunderstood accounting categories, quadrupled assumptions about methane’s relative greenhouse potential — and then only in the short term, when people like Black are always telling us it is the long term we should worry about.
A review from Michael Levi of CFR (again, the whole thing is worth reading):
First, the data for leakage from well completions and pipelines, which is where he’s finding most of his methane leaks, is really bad. Howarth used what he could get – figures for well completion leakage from a few isolated cases reported in industry magazines, and numbers for pipeline leakage from long-distance pipelines in Russia – but what he could get was very thin. There is simply no way to know (without access to much more data) if the numbers he uses are at all representative of reality.
Second, Howarth’s gas-to-coal comparisons are all done on a per energy unit basis. That means that he compares the amount of emissions involved in producing a gigajoule of coal with the amount involved in producing a gigajoule of gas. (Don’t worry if you don’t know what a gigajoule is – it doesn’t really matter.) Here’s the thing: modern gas power generation technology is a lot more efficient than modern coal generation, so a gigajoule of gas produces a lot more electricity than a gigajoule of coal. The per kWh comparison is the correct one, but Howarth doesn’t do it. This is an unforgivable methodological flaw; correcting for it strongly tilts Howarth’s calculations back toward gas, even if you accept everything else he says.
One last comment: I worry about what this paper says about the peer review process and the way the press treats it. This article was published in a peer-reviewed journal that’s edited by talented academics. It presumably got a couple good reviews, since its time from submission to publication was quite short. These reviewers don’t appear to have been on the ball. Alas, this sort of thing is inevitable in academic publishing. It’s a useful caution, though, against treating peer review as a mark of infallibility, as too many in the climate debate – both media and advocates – have done.
The weak data and unorthodox methodology should make one question its ultimate conclusion, and it doesn’t help that the author is apparently an anti-fracking advocate. The EPA has already called this study an “important piece of information” and it has been reported on without mentioning the critiques in a number of media outlets (and here). Some outlets were better:
Mark D. Whitley, a senior vice president for engineering and technology with Range Resources, a gas drilling company with operations in several regions of the country, said the losses suggested by Mr. Howarth’s study were simply too high.
“These are huge numbers,” he said. “That the industry would let what amounts to trillions of cubic feet of gas get away from us doesn’t make any sense. That’s not the business that we’re in.”
Most business models don’t include plans to allow billions of dollars of your product to escape into the atmosphere.