3) Running out of fuel. Again, this comes with a big caveat. We're suddenly finding huge amounts of fossil fuels You're right, we're not going to run out of oi

3) Running out of fuel. Again, this comes with a big caveat. We're suddenly finding huge amounts of fossil fuels You're right, we're not going to run out of oil in an absolute sense - but we're unlikely ever to be able to get the stuff out of the ground faster than we're doing now. See http://www.indexmundi.com/energy.aspx?product=oil&graph=production http://www.indexmundi.com/energy.aspx?product=oil&graph=... for a nice illustration, and bear in mind that the last few years have been at record oil prices, so if there was any room to grow production, we'd expect it to have done so. Limited supply and growing demand means rising prices. I think this is a self-fixing problem to a large extent as higher prices will mean alternatives become cost-effective, but steadily- and sharply-rising energy prices does seem as safe a long bet as one could take.