July 16, 2012 A debate has raged in the past couple of years as to whether natural gas is better or worse overall than coal and oil from a global warming perspective. The back-and-forth findings have been due to the timelines taken into consideration, the details of natural gas extraction, and the electricity-generating efficiency of various fuels. An analysis by Cathles, which focuses exclusively on potential warming and ignores secondary considerations, such as economic, political, or other environmental concerns, finds that natural gas is better for electricity generation than coal and oil under all realistic circumstances.
To come to this conclusion, the author considered three different future fuel consumption scenarios:
(1) a business-as-usual case, which sees energy generation capacity continue at its current pace with its current energy mix until the middle of the century, at which point the implementation of low-carbon energy sources dominates and fossil fuel-derived energy production declines;
(2) a gas substitution scenario, where natural gas replaces all coal power production and any new oil-powered facilities, with the same midcentury shift; and
(3) a low-carbon scenario, where all electricity generation is immediately and aggressively switched to non-fossil fuel sources such as solar, wind, and nuclear.
The author finds that the gas substitution scenario would realize 40 percent of the reduction in global warming that could be achieved with a full switch to low-carbon fuel sources. The benefit for mitigating warming revolves around the fact that to produce an equivalent amount of electricity burning natural gas would release less carbon dioxide than burning oil or coal. Though atmospheric methane traps more outgoing radiation than carbon dioxide does, at reasonable leakage rates its atmospheric concentration is much lower and what is released decomposes much more quickly. The author suggests that over timescales relevant to large-scale warming -- decades to centuries -- the effect of any methane released during natural gas extraction would be inconsequential.
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- L. M. Cathles. Assessing the greenhouse impact of natural gas. Geochemistry Geophysics Geosystems, 2012; 13 DOI: 10.1029/2012GC004032
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