Actually, this is a straw man argument. I don't know anyone who thinks that peak oil will prevent climate change. There's certainly enough oil left to take us to the point where natural positive feedbacks will make global warming irreversible.

Everyone that I've spoken to about peak oil has been disappointed to hear that. On the other hand, it's a good way to convince skeptics that we need to be taking action to reduce oil usage regardless of what they think about the climate.