My thesis is that the knowledge on its own wouldn't be enough. To reflect a later commenter, suppose we still knew how to make shale gas. We still need all the

My thesis is that the knowledge on its own wouldn't be enough. To reflect a later commenter, suppose we still knew how to make shale gas. We still need all the infrastructure involved in getting shale gas - which needs other infrastructure, which needs us to have some other easily available resources. All those resources might be gone.