Not so long ago it seemed the world's addiction to fossil fuels would soon be ended by dwindling supply. But that was before fracking, tar sands and deep sea exploration transformed calculations about global reserves of oil and gas. HARDtalk speaks to Fatih Birol - one of the world's most influential analysts of the global energy market and its effect on the world economy and environment. Is the resilience of fossil fuel supply a cause for celebration, or despair?