Drawbacks to natural gas.

E. Kintisch recently reported on the evolution of the climate stabilization wedge concept (“Climate study highlights wedge issue,” News & Analysis, 11 January, p. [128][1]), first conceptualized by Pacala and Socolow in 2004 ([ 1 ][2]). At the close of the News story, Socolow acknowledges the need for thoughtful assessment of the technological paths toward carbon neutrality, but not before he touts the recent expansion of natural gas as “a rare sign of progress.” Natural gas is increasingly held up as a clean-burning, domestic “bridge fuel” paving the way toward energy independence. The problem with this assertion is that the recent proliferation of U.S. natural gas production is largely due to the expansion of hydraulic fracturing methodology to access shale gas ([ 2 ][3]). Once extracted, natural gas burns cleaner than coal or oil; however, the extraction-to-consumer carbon footprint of hydraulically fractured natural gas is greater than that of traditional energy sources ([ 3 ][4]). Moreover, hydraulic fracturing is increasingly linked with potentially irremediable freshwater contamination. In Pavillion, Wyoming, for instance, toxic or carcinogenic compounds added to fracking fluid have been found in drinking wells adjacent to drill pads ([ 4 ][5]). As we grapple with how to meet society's energy demands while obtaining carbon neutrality, we cannot pay for carbon offsets at the expense of other valuable natural resources, such as fresh water. ![Figure][1] Shale gas well site. CREDIT: DWIGHT NADIG/ISTOCKPHOTO 1. [↵][6]1. S. Pacala, 2. R. Socolow , Science 305, 968 (2004). [OpenUrl][7][Abstract/FREE Full Text][8] 2. [↵][9]Energy Information Administration, “Annual energy outlook” (U.S. Department of Energy, Washington, DC, 2011). 3. [↵][10]1. R. W. Howarth, 2. R. Santoro, 3. A. Ingraffea , Clim. Change 106, 679 (2011). [OpenUrl][11][CrossRef][12][Web of Science][13] 4. [↵][14]1. D. C. DiGiulio, 2. R. T. Wilkin, 3. C. Miller, 4. G. Oberly , “Draft: Investigation of ground water contamination near Pavillion, Wyoming” (EPA, Office of Research and Development, Ada, OK, 2011); [www.epa.gov/region8/superfund/wy/pavillion/EPA\_ReportOnPavillion\_Dec-8-2011.pdf][15]. [1]: pending:yes [2]: #ref-1 [3]: #ref-2 [4]: #ref-3 [5]: #ref-4 [6]: #xref-ref-1-1 "View reference 1 in text" [7]: {openurl}?query=rft.jtitle%253DScience%26rft.stitle%253DScience%26rft.aulast%253DPacala%26rft.auinit1%253DS.%26rft.volume%253D305%26rft.issue%253D5686%26rft.spage%253D968%26rft.epage%253D972%26rft.atitle%253DStabilization%2BWedges%253A%2BSolving%2Bthe%2BClimate%2BProblem%2Bfor%2Bthe%2BNext%2B50%2BYears%2Bwith%2BCurrent%2BTechnologies%26rft_id%253Dinfo%253Adoi%252F10.1126%252Fscience.1100103%26rft_id%253Dinfo%253Apmid%252F15310891%26rft.genre%253Darticle%26rft_val_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Ajournal%26ctx_ver%253DZ39.88-2004%26url_ver%253DZ39.88-2004%26url_ctx_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Actx [8]: /lookup/ijlink/YTozOntzOjQ6InBhdGgiO3M6MTQ6Ii9sb29rdXAvaWpsaW5rIjtzOjU6InF1ZXJ5IjthOjQ6e3M6ODoibGlua1R5cGUiO3M6NDoiQUJTVCI7czoxMToiam91cm5hbENvZGUiO3M6Mzoic2NpIjtzOjU6InJlc2lkIjtzOjEyOiIzMDUvNTY4Ni85NjgiO3M6NDoiYXRvbSI7czoyNDoiL3NjaS8zNDAvNjEyOS8xNDEuMS5hdG9tIjt9czo4OiJmcmFnbWVudCI7czowOiIiO30= [9]: #xref-ref-2-1 "View reference 2 in text" [10]: #xref-ref-3-1 "View reference 3 in text" [11]: {openurl}?query=rft.jtitle%253DClim.%2BChange%26rft.volume%253D106%26rft.spage%253D679%26rft_id%253Dinfo%253Adoi%252F10.1007%252Fs10584-011-0061-5%26rft.genre%253Darticle%26rft_val_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Ajournal%26ctx_ver%253DZ39.88-2004%26url_ver%253DZ39.88-2004%26url_ctx_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Actx [12]: /lookup/external-ref?access_num=10.1007/s10584-011-0061-5&link_type=DOI [13]: /lookup/external-ref?access_num=000290449200010&link_type=ISI [14]: #xref-ref-4-1 "View reference 4 in text" [15]: http://www.epa.gov/region8/superfund/wy/pavillion/EPA_ReportOnPavillion_Dec-8-2011.pdf