Fracking, shale gas and climate change

There's been an interesting exchange of emails in the Guardian recently regarding climate change, shale gas and fracking.

July 2, 2013 had several letters for and against this source of energy for the UK. David England stated that methane is 200% as effective as a greenhouse gas as carbon dioxide and that therefore methane leakage of shale gas reduces its low-carbon credentials. He mentions concerns in the US that as much as 16% of methane may be lost in fracking operations.

On July 3 David Hookes corrects England's figure of 200% to 2000% and quotes a figure from a study at Cornell University that suggests a leakage of only 5% would cancel out the apparent gain from using shale gas rather than coal.

On July 5 Peter Hansen confirms Hookes's figure (well; he quotes methane being 21 times worse than carbon dioxide which is 2100%  but let's  not quibble), and suggests that with 16% leakage of methane this fuel would cause over 50% more greenhouse warming than using coal.

So Hookes and Hansen are, roughly speaking, in agreement and the claim that using methane extracted by fracking as a fuel helps mitigate climate change looks pretty dubious.

Roger Oliver (8/7/13)