German environment minister Norbert Roettgen says the Copenhagen summit will fail if there is no agreement to limit the rise in the earth's temperature to two degrees. Roettgen called on Germans to buy cars that are less environmentally harmful. But critics at home accuse Roettgen, a CDU party member, of harming the environment by announcing cuts to solar energy subsidies. Ahead of his departure, for Copenhagen, the minister met some young environmental activists....