US 'will become one of the world's top gas exporters by 2020'

IEA says growth in production, as fracking opens up shale oil and gas deposits, will see US rival Russia and Norway

The American shale gas revolution will enjoy a second wind as rapid growth in domestic production sees the US join the world's club of top gas exporters, a leading energy authority has predicted.

Fracking has already opened up US shale oil and gas deposits, leading to a fall in gas prices and greenhouse gas emissions as power generation switches from coal to gas, as well as reducing America's historical reliance on fossil fuel imports.