There is every likelihood that we could in principle just keep drilling new oil. Our ability to extract oil at a cost effective rate scales almost exactly with the depletion of easy reserves. The reason we need to switch out is the devastating environmental impact, and only the devastating environmental impact.
It's not the drilling, but leaks of oil, gas, fires and obviously actually burning this fuel without full recapture. (Not offset, that is insufficient and sleigh of hand.)
