Produced energy and the pattern of human population growth from 1750. Utilization of these energy sources, together with the energy used by humans from net primary production, is now approaching the entire energy available to the global ecosystem before human intervention [Barnosky, [1]]. Key to colours: dark blue = coal; dark brown = oil; green = natural gas; purple = nuclear; light blue = hydro; orange brown = biomass (e.g. plants, trees). Data source from http://www.theoildrum.com/node/8936