Knut was the perfect mascot for the Green moment, splashed on the cover of Vanity Fair. Now? He's a quivering, angry mess. A cautionary tale of animal celebrity Consider the effect of climate change on animals and it's the polar bear that invariably comes to mind, majestically astride a thinning ice floe, watching its habitat disappear.The species is a powerful conservation symbol. But how much is it, and the public's dawning enviro-consciousness, being cynically exploited because of it?The story of two German polar bear cubs raises the question. It's a cautionary tale, sprinkled with fairy dust at the start, now...