Petrocollapse isn't the danger. We will not run out of oil - just the cheap oil we have become used to - but depletion of our socio-economy's primary fuel has made us vulnerable to a Great Depression style dislocation. Commentators predict variants of the following scenario:

• oil spikes upwards over $100 a barrel, perhaps $200 a barrel;
• companies in key industries - airlines, tourism, distribution, etc. - go bankrupt and resulting deflation pounds existing speculative bubbles - real estate, stock markets - which burst and, as the deflation accelerates, lack of demand plus increased energy costs for production and distribution, plus strikes/fuel price protests, rapidly paralyses existing trade.