Prof Howarth remains the king of media and distortion. Just published by Climate Letters, Howarth's reponse to the avalanche of academic studies that took apart his original work claiming that gas's global warming emissions are greater than coal's has already drawn more media than did the multiple studies critiquing him. I will add in my small way to the attention given Howarth, though this blog has postings on the Carnegie Mellon University, Worldwatch Institute, University of Maryland, National Energy Technology Laboratory, and the competing Cornell studies. Here is the link to the Howarth response: http://22.214.171.124/HowarthIngraffeaarticleFINAL1.pdf.
Paid for by the Park Foundation that is financing the most aggressive anti-shale gas advocacy, Howarth's response with one big and one small exception is simply a repeat of his paper and its extreme assumptions that all head in one direction--skewing numbers to make coal look cleaner than gas. The big exception involves an area of agreement between Professor Howarth and myself--the importance of the EPA proposed July 2011 proposed rule on air emissions.
Howarth now says of July 11, 2011 EPA proposed rule on air emissions from gas drilling: "EPA...estimates the regulation would reduce flowback emissions from shale gas wells by up to 95%, although gas capture would only be required for wells where collector pipelines are already in place, which is often not the case when new sites are developed. Nonetheless, this is a very important step, and if the regulation is adopted and can be adequately enforced, will reduce greatly the difference in emissions between shale gas and conventional gas in the U.S. We urge universal adoption of gas-capture policies."
Later Howarth adds at page 11 of his response: "Can shale-gas methane emissions be reduced? Clearly yes, and proposed EPA regulations to require capture of gas at the time of well completions are an important step."
The above is an indirect way of Howarth saying that even he would concede his fugitive methane emission assumptions would no longer stand if the EPA rule is promulgated and enforced.
The only other small concession Howarth makes in his response is to concede that the assumption in his original paper that 100% of flowback gas is vented is wrong. "Note that estimates we published in Howarth et al. (2011) for emissions at the time of well completion for shale gas could be reduced by 15%..." See discussion at page 6. This is a small, inadequate concession. Based on my experience in the Marcellus, Howarth's estimate that 85% of all flowback gas for a 10-day period is vented, as opposed to flared or captured, remains a huge exaggeration.
In the rest of the paper, Howarth makes no adjustments for leakage rates from shale gas to reflect the fact that the pipes and infrastructure being deployed in these new plays is of course new and very high quality, with low leakage problems. In fact, for this reason, shale gas infrastructure almost certainly has lower leakage rates than the infrastructure serving conventional gas wells that often is decades old.
Howarth continues to reject and attack the IPCC's 100-year period for estimating the global warming potential of natural gas. Methane comparatively quickly dissipates compared to carbon dioxide, with most of it gone within 15 years. Consequently, were Howarth to accept the science published by the Intergovernmental Panel on Climate Change, his paper substantially collapses so he attacks the IPCC science consensus.
Howarth continues to refuse to do a full life cycle comparison of coal and gas through combustion, refusing to even deal with the fact that nearly 100% of coal is combusted in power plants. Nobody disputes that the carbon emissions from burning coal at a power plant are vastly greater than carbon emissions using gas. But Howarth just stops his life cycle analysis prior to combustion at the power plant, because again his paper essentially collapses if he did not.
The paper does nothing to make clear to the public and reporters that even Howarth is not arguing that gas is dirtier than coal on emissions like mercury, arsenic, lead, soot and all the pollutants that directly sicken and kill people. The failure to do so is most unfortunate, because many people simply hear the Howarth claim that gas is dirtier than coal and do not understand that Howarth is focusing only on global warming pollution. This is a prevalent confusion not directly sowed by Howarth, but one which he shows no interest in correcting.
Yet, to end on a hopeful note, Howarth's concession that the EPA proposed July 2011 rulemaking is a game changer is important. For that point and that alone, I will thank Professor Howarth.