"This paper presents a new formula for calculating when fossil fuel reserves are likely to be depleted and develops an econometrics model to demonstrate the relationship between fossil fuel reserves and some main variables. The new formula is modified from the Klass model and thus assumes a continuous compound rate and computes fossil fuel reserve depletion times for oil, coal and gas of approximately 35, 107 and 37 years, respectively. This means that coal reserves are available up to 2112, and will be the only fossil fuel remaining after 2042." http://www.peakoil.net/publications/when-will-fossil-fuel-reserves-be-diminished
Current trends cannot be continued until 2100. There isn't enough fossil fuel. All the easily reachable oil is going to be burned and go into the atmosphere, no matter how successful the attempts to curb global warming. If we dramatically curb the use of fossil fuels, it will simply take a little longer to burn it all up. But it is all going into the atmosphere. There is no political force strong enough to tell all the people of the world they can't run their cars or heat their homes with fossil fuels any more. Since is entirely futile to stop all the easily extracted fossil fuel from being burned, there is no point in debating how to curb emissions. Our focus should be on what we can do to minimize the impact.