Hello @gavvet Good Post.
The estimations on Fossil Fuels running out in 53 years don't consider Fracking. Controversial Topic I admit, but the reserves held in shale based reserves are incredibly vast. It's hard to get actually numbers, but from what i understand, there is more Fracking potential in the world than conventional basin reserves.
I can't see this happening in our lifetime, however I hope we get our acts together and Clean Energy takes over way before we need to worry about it..