World leaders gathered at a UN climate summit in New York recently and pledged again to tackle global warming. Yet again this year global greenhouse emissions have risen, partly because many politicians and citizens don't want more expensive renewable energy if it costs economic growth and prosperity. Hardtalk speaks to the British climate economist, Lord Nicholas Stern, who has just co-chaired a new report on the climate and economy. He says, it is not an either or situation. But what evidence is there that we can have it both ways and are governments listening?(Photo: Lord Nicholas Stern. Credit: Hannelore Foerster/Getty Images)