Here's a good article on the subject, by David Strahan. He discusses why Climate Change campaigners don't want to discuss Peak Oil and vice versa, despite the obvious interdependence of the two subjects.
Peak oil could also sabotage attempts to fight climate change by paradoxically increasing greenhouse gas emissions, if oil depletion forces us to exploit the wrong kinds of fuel. The alternatives to crude oil are all resource constrained and unlikely to fill the gap – at least not in time – but they still have the potential to do enormous climate damage. Burning rainforest and peatlands to create palm oil plantations for biofuels releases vast amounts of CO2, and has already turned Indonesia into the world’s third biggest emitter after America and China. Synthetic transport fuels made from gas using the Fischer-Tropsch chemical process emit even more carbon on a well-to-wheels basis than conventional crude. When the feedstock is coal the emissions double. So in the unlikely scenario that we manage to replace more than half the yawning conventional deficit with coal-based fuel, but not all of it, we would still suffer fuel shortage while emitting even more CO2 than in the current business-as-usual forecast - the worst of all possible worlds.