The First problem with predictions about "Peak Oil", or peak anything for that matter, is that it assumes the current known reservers are all that exist. The Second problem with these predictions are that they don't take into account the ability of price and new technology to change what known quantities of a natural resource even get counted in the reserves.
The known reserves of Oil is higher today than it was during the oil shortages of the 1970's here in the US. This is becuase exploration continues to find new reserves. Furthermore, the Candian oil sands were known about in the 1970's, but excluded from the estimates of global reserves becuase, at 1970's prices and using 1970's technology, it was not possible to extract the oil and sell it for a profit. Both prices and technology changed, and now the Canadian oil sands are included in global reserves calculations. Also, wells are not pumped dry. They are frequently shut off when the costs associated with extraction are greater thant he price the oil can be sold for. As prices go down, producing fields are capped until prices go back up and the field can be operated without a loss. Steam injection and other techniques have made it possible to get more oil out of a well at a lower cost than was possible 40 years ago, and I see no reason to believe that this advance of technology is going to reach it's apex with current technology. The financial incentives to come up with new technologies are just too great.
This is all very clearly discussed in "Basic Economics, 4th edition" by Thomas Sowell. I'm currently listening to the Audiobook during my weekday commute and it is very understandable and quite convincing.
Now, this doesn't address the AGW issues associated with use of fossile fuels directly. However, by using up the cheap easily-accessible oil we will create an economic situation where alternatives that are currently not cost effective (with or without government intervention) will become cost effective at somepoint without increasing their cost per unit of energy. Furthermore, as each alternative technology gets closer to cost effective, investement capital will be injected into R&D to try and be the first to hit the market in a cost effective manner and reap the benefits that come from being first and getting the lions share of the market to start.