Peak oil has probably come and gone, but to focus on that is misleading.
The real resource problem we're seeing is continuously declining energy return from hydrocarbons.
In the 1960s, we were seeing, for example, returns of 100:1 in West Texas oil fields. Production was cheap. Profits, both economically and energetically were huge. Fast forward to 2012. These days a good energy return is 10:1. A 10-fold decrease in 50 years.
In 2005, a funny thing happened. Energy prices started to climb, and they're still climbing, even during a global financial crisis (
http://inflationdata.com/inflation/infl ... _chart.asp).
The reason is straightforward. Oil, for example, contributes 160 exajoules a year to the world. It now takes much more money and energy to generate that 160 exajoules than it did 10 or 20 years ago. The oil that's left, is harder to get, entails more risk (and more insurance), is in many separate scattered small reservoirs, making it more expensive to drill. The end result that we see is higher prices.
Eventually, prices go high enough to start breaking supply chains, including the supply chains that provide energy. That decidedly nonlinear, nongradual break is something to watch out for. When it happens, there will still be plenty of oil in the ground, it's just that we'll never be able to use it.