Moving from burning coal to generating electricity from shale gas in the US is not cutting carbon emissions at the rate originally estimated.
Gas produces lower emissions than coal, and the US is now burning less coal to generate electricity because of the development of unconventional gas reserves in shale rock. But millions of tonnes of unused coal is now being exported to the UK, Europe and Asia, say researchers from the Tyndall Centre for Climate Change.
While emissions from the US energy sector have declined by 8.6 per cent, reductions could simply have been displaced.