US CO2 emissions from domestic energy have declined by 8.6% since a peak in 2005, the equivalent of 1.4% per year. However, the researchers warn that more than half of the recent emissions reductions in the power sector may be displaced overseas by the trade in coal.

Dr John Broderick, lead author on the report from the Tyndall Centre for Climate Change Research, comments: "Research papers and newspaper column inches have focussed on the relative emissions from coal and gas.

"However, it is the total quantity of CO2 from the energy system that matters to the climate. Despite lower-carbon rhetoric, shale gas is still a carbon intensive energy source. We must seriously consider whether a so-called "golden age" would be little more than a gilded cage, locking us into a high-carbon future."

Professor Kevin Anderson of the Tyndall Centre notes: "Since 2008 when the shale gas supply became significant, there has been a large increase in US coal exports.

This increases global emissions as the UK, Europe and Asia are burning the coal instead. Earlier Tyndall analysis suggests that the role for gas in a low carbon transition is extremely limited, with shale gas potentially diverting substantial funds away from genuinely low and zero carbon alternatives"

This Co-operative commissioned report "Has US Shale Gas Reduced CO2 Emissions?" is the third on shale gas from the Tyndall Centre - and builds on several years of research and submissions to the UK and European Parliaments as well as the International Energy Agency.

Chris Shearlock, Sustainable Development Manager at The Co-operative, said: "The proponents of shale gas have always claimed that it is a lower carbon alternative to coal.

"However, this is only true if the coal it displaces remains in the ground and isn't just burnt elsewhere. Without a cap on global carbon emissions, shale gas is burnt in addition to other fossil fuels, increasing total emissions."