Sharon Astyk in Casaubon's Book:
Let us imagine human beings climbing up a rather steep and precarious tree, boosted up by fossil energies into a place we simply could never get to without them. The problems we are facing right now all originate in our fundamental inability to voluntarily set limits – that is, at no point did most of us even recognize the basic necessity of stopping at a point at which we could get down on our own, without our petrocarbon helpers. So right now we look like Tiggers high in the trees – we can climb up but we can't climb down. Is the problem our fears or that our tails (our structural addictions to energy) get in the way? It can be hard to tell. But what is not terribly hard to tell is that one way or another, we have to come down – and probably quite rapidly. The goal is to avoid a painful “thud” upon descent.
Why do we have to come down? Well, there are two compelling reasons, which will be entirely familiar to my regular readers, but perhaps are worth rehashing. The first is this. We can't keep burning fossil fuels – period. And we have very, very little time to make our choices not nearly as much time as we need to make a smooth, easy descent.
The problems we face have several names. Peak oil, which the Hirsch report suggests requires a 20 year lead time before we reach an oil peak – a peak that even optimistic sources suggest is much less than 20 years from now (the USGS, for example, uses 2023, many sources suggest much sooner – the US Army JOE report anticipates major constraints within 2-5 years).
But even if we had all the fossil fuels we wanted, we know we can't burn them.
More here.