Peak oil! I bang on about this at every given chance, but I think it's worth it.

Say there are 100 years of oil left. (Oil companies come out with this sort of number all the time, and it's a nice reassuring number because we all expect to be dead by then).

Peak oil means that we actually have a lot less time to get our shit together than those supposed 100 years of oil implies.

Peak oil is the moment when we reach maximum oil production. It means we've used about half of the oil in the ground. Because it was easier, we also probably used all the easy to reach oil first. So what we have left are a lot of dregs. Oil at the bottom of the ocean (remember the Gulf of Mexico spill?), oil extracted from tarsands (requires billions of gallons of freshwater to unmix - another delpeting commodity), oil in ecologically sensitive areas (big row over Alaska, for example).

All of this adds up to one outcome: there's always going to be less and less oil from now on, and it's always going to be harder and harder to get. Which means oil costs a shitload more than than it used to. We don't have to wait for that to happen, everyone already feels it in their wallet.

Before long, a barrel of oil costs more to produce than most people can afford to pay to fill up their cars. Even with say 90 "years worth" left in the ground, that's the real crisis point. There's already plenty of people who can't afford to fill up their cars anymore. Eventually, that will be all but the most priveleged.

(By the way, oil isn't just energy, it's also all plastics, resins, paints, fertilisers, cosmetics, modern medicines - it's industrial civilisation, and there is no alternative.)

What I'm trying to say is, we're even more screwed than that article implies.