The Canadian Fur Council http://www.furcouncil.com/Conservation.aspx says that real fur is more environmentally sound than synthetic, because fake fur uses petrochemicals which causes pollution and contributes to global warming.
First I must say that I love it when crazy environmentalists battle with big corporations pretending to be crazy environmentalists, who may actually have a case. Next I must say that the logic here is terrible! Just because A is better than B doesn't mean that you can't do neither. Using all natural clothing, made from hemp, would be better than either. This is really just a way for rich people to feel better about themselves.