Resource use and economic development: an exergy perspective on energy and material flows and stocks from 1900 to 2010

Energy and materials support food production, maintain and expand material stocks (e.g. buildings and roads) and provide services. In this paper, an exergy-based approach is used to provide an integrated perspective on the evolution of societal resource flows and stocks. The scope of this analysis is from resource extraction (primary exergy stage) to end uses such as low temperature heating and illumination (useful exergy stage). From 1900 to 2010, global exergy consumption at the primary stage increased from 115 to 903 EJ/year, of which 88–89% corresponded to energy flows, including food and feed. Useful exergy flows increased from 9 to 148 EJ/year, of which 47%, in 2010, was contained within material goods. Primary to useful efficiency doubled from 8% in 1900 to 16% in 2010. However, this improvement is far from that which is required to achieve climate targets for 2060. The amount of resource flows required per unit of economic activity decreased at both the primary (from 58.5 to 17.0 GJ/$) and useful (from 4.7 to 2.8 GJ/$) exergy stages, indicating relative decoupling. The exergy in stocks went from 91 to 820 EJ. Stock intensity reduced from 46.2 to 15.5 GJ/$-year−1 due to a shift in stock composition rather than dematerialisation in mass terms. Future research needs to identify the relationships between resource flow intensity and stock intensity in order to meet sustainability targets, including those linked to future resource demand. The scope could be expanded to include additional resources such as water and rare earth metals