By Zeke Hausfather | May 5, 2011
Global Warming Potentials:
A recent analysis concluding that natural gas from shale poses more climate change problems than combustion of coal rests heavily on a problematic time frame. In the end, the widely reported article may do more to muddle understanding of natural gas vs. coal than to clarify it.
A recent article in the journal Climatic Change by Robert Howarth and his colleagues argues that natural gas from shale formations is worse for the climate than coal. This controversial finding has been widely reported in the media, but has also been subject to criticism from a wide variety of sources.
Critics say that the Howarth et al analysis used an unrealistically short time frame for estimating the warming effect of methane emissions, and they say Howarth did not take into account the relative efficiency of converting coal and natural gas into useful energy. When these factors are taken into account, electricity generation from natural gas emits one-third to one-half less carbon than coal, a range comparable to prior estimates.