pleather thou?

I was thinking about something totally different tonight, and somehow two things converged in my head, and I started wondering.

How does the carbon footprint of leather shoes compare with those made out of petro-chemicals?

I think this popped up because I was reading about PETA's public statement that one cannot be an environmentalist while consuming animal products and then I started thinking about how I really can't see myself wearing clothes that are made of artificial fibres, and it kind of snowballed from there. Most leather comes from cows which are horrible for the environment. Artificial substitutes are made from a non-renewable resource, but the issue is less about running out of the stuff as it is what kind of mess we make using it.

So what do you think?