How the 2010s became another lost decade in the fight against climate change when the move to natural gas delayed a transition to more renewable sources of energy. Engineer Tony Ingraffea explains how, in the 1980s, he helped develop a new technique for extracting gas and oil from shale rock, which became known as 'fracking'. It was to unleash vast new reserves of fossil fuels and promoted as a cleaner energy source. But Ingraffea explains how he later came to regret his work.

S1 Ep3 60min