The historical and deductive merits for an explicit energy-based economic growth formulation are presented. Parameters in the formulation are successfully calibrated to empirical data and a range of forecasts is made for global economic growth potential to 2050, based on a plausible case of energy availability. The results demonstrate the vital importance of energy security and lead to the conclusion that the current socio-economic paradigm may not be sustainable. (C) 2009 Elsevier Ltd. All rights reserved.