Justin Rowlatt reports on whether President Obama is on target to keep his climate change promises. Travelling across the States, using public transport only, Justin encounters coal miners and car manufacturers; activists and politicians; a pig farmer and a film star. He goes ice-fishing in Michigan, finds a thriving wind industry in the oil state of Texas and, in Detroit, drives a test car of the future. The film reveals two very different sides of America - the people who agree with their president that the US should be leading the world on tackling global warming, and those who see Obama's plans as an attack on their liberties. And it's not surprising that, in this divided America, the president's push to limit greenhouse gas emission has become stuck in the mud of Washington politics.