"A new study in the Proceedings of the National Academies of Science concludes that hydraulic fracturing–the controversial technique behind the nation’s recent oil and gas boom–doesn’t appear to contribute significantly to global warming, as many environmental groups have warned....
Many environmental groups fear that the process can contaminate underground water supplies–and also that it releases underground stores of methane, a potent greenhouse gas that can have 20 times more impact on global warming than carbon dioxide.
The White House and EPA “have expressed great interest in the findings,” said David Allen, a professor of chemical engineering at the University of Texas and the lead author of the study. Allen has been invited to brief EPA and other administration officials on the research....
The study concluded that the majority of hydraulically fractured natural-gas wells have surface equipment that reduces on-the-ground methane emissions by 99 percent, although it also found that elsewhere on fracking rigs, some valves do allow methane to escape at levels 30 percent higher than those set by EPA. Overall, however, the study concludes that total methane emissions from fracking are about 10 percent lower than levels set by EPA....
University of Texas researchers say their yearlong study, which involved measuring methane emissions from 190 natural-gas production sites in the Gulf Coast, midcontinent, Rocky Mountains, and Appalachia, is far more comprehensive than the (2011) Cornell study, which relied on existing data rather than new fieldwork."...
9/16/13, "Measurements of methane emissions at natural gas production sites in the United States," PNAS
- David T. Allena,1,Vincent M. Torresa, James Thomasa, David W. Sullivana,
- Matthew Harrisonb, Al Hendlerb, Scott C. Herndonc, Charles E. Kolbc,
- Matthew P. Fraserd, A. Daniel Hille, Brian K. Lambf, Jennifer Miskiminsg,
- Robert F. Sawyerh, and John H. Seinfeld iAuthor Affiliations" ================================
“Fig. 1. Monthly global atmospheric CO2“
"In our analysis we use eight well-known datasets:
1) globally averaged well-mixed marine boundary layer CO2 data,
2) HadCRUT3 surface air temperature data,
3) GISS surface air temperature data,
4) NCDC surface air temperature data,
5) HadSST2 sea surface data,
6) UAH lower troposphere temperature data series,
7) CDIAC data on release of anthropogene CO2, and
8) GWP data on volcanic eruptions....
Changes in CO2 always lagging changes in temperature."...