Their work has been challenged (condemned?) by at least 12 other sources - amongst them
May 2011, U.S. Dept. of Energy report: Emissions from natural gas are low compared to other fuels.
- 'Howarth [and Ingraffea] found a large fraction of produced gas from unconventional wells never made it to end users, assumed that all of that gas was vented as methane, and thus concluded that the global warming impacts were huge. As the [Dept. of Energy] work explains, though, 62% of that gas isn't lost at all, it's used to power equipment.'
- 'Ingraffea's and Howarth's analysis is seriously flawed in that they significantly overestimate the fugitive emissions associated with unconventional gas extraction .....'
- 'The assumptions used by Howarth et al. are inappropriate and ....... their data, which the authors themselves characterize as 'limited', do not support their conclusions'.
- 'Professor Howarth's & Ingraffea's conclusion that gas emits more heat trapping gas than carbon, flies in the face of numerous life cycle studies done around the world'.
- 'Professor Howarth & Ingraffea just adopted an extreme and false assumption of no flaring that conveniently moved the result of his life cycle analysis in the direction that he wanted'.
- 'The GHG emission estimates shown here for Marcellus gas are similar to current domestic gas.'
- 'For comparison purposes, Marcellus shale gas adds only 3% more emissions to the average conventional gas, which is likely within the uncertainty bounds of the study. Marcellus shale gas has lower GHG emissions relative to coal when used to generate electricity.'
- 'Lead researcher Paula Jaramillo (with reference to Ingraffea and Howarth's paper): 'We don't think they're using credible data and some of the assumptions they're making are biased. And the comparison they make at the end, my biggest problem, is wrong.'
I do not think we should publicise one side or the other in this debate. We certainly should not provide a link to a biased source.
The only defensible link would be to http://www2.epa.gov/hydraulicfracturing
this is the regulatory authority which is currently conducting a 5 year R&D program into the impact of hydraulic fracturing. So far the news flow has not been kind to Professor Ingraffea's position.