I am convinced that depletion of the super-giant oil fields, that the global economy depends on, is occurring now. Although production and enhanced oil recovery data is closely held, looking at the production data that is available, from sources such as this, there is little doubt. The slope of decline can be steep from an exhausted field with respect to production.
Given that situation, consider this interview which predicts the consequences of expensive oil on the global economy. There are numerous blogs looking at elements of the material presented, but this is worth considering.
The waste of energy and inefficiency in our transportation, heating and industrial activity amazes me. Increased efficiency are the low-hanging fruit with respect to expensive hydrocarbons.