The Times, 23 September 2013:
Your claim that shale gas is better for the environment than coal does not stack up (Frack Baby Frack July 20) as shale gas (methane) is a potent greenhouse gas, twenty times more powerful than CO2 over a 100 year time frame. Whilst burning gas releases less CO2 per unit of energy than coal, this benefit is negated by releases of methane during the fracking process. Calculations published by Professor Tom Wigley in the journal Climatic Change in 2011 show that unless fugitive emissions of methane are kept below 2%, then shale gas is no better than coal from a global warming perspective. In the US fugitive emissions have been running at around 7%, and the fossil fuel industry has been strenuously resisting methane control legislation proposed by the EPA. This explains why shale gas in the US is cheap, but also means that America’s new energy mix is making climate change worse not better.
There is no link to the original article as it is behind a paywall.