Not exactly news that our current energy consumption growth rate is unsustainable, but here's a pretty need summary anyway. I at least was surprised by the numbers.
http://physics.ucsd.edu/do-the-math/...-scale-energy/
As a short paraphrase (capturing only a part of the whole thing), at current growth rate, in 400 years we could need to cover the whole surface of Earth (seas included) with 100% efficiency solar panels to satisfy our energy needs.