The links between economic prosperity, or lack thereof, and the exploitation and use of energy and other natural resources go back to the earliest records of the human species - and in important respects even further back to when hunting and foraging characterised the earliest humanoid species. This paper surveys the challenges of resource exploitation and use, reflecting that as we exploit the most readily and cheapest resources, and extraction technology, available at the time, so the marginal returns of each tend to decline as the highest quality is depleted, costs rise, and alternatives are increasingly sought. There are few resources where this is truer than the various forms of energy which have been exploited down the ages. Many complex societies in the past have failed to make a successful transition, and the historic record demonstrates clearly the inadequacies of Solow-type growth theory. Scenarios of global energy prospects for the 21st Century need to consider the past and, in the light of it, ask whether the end of the Anthropocene Age is in sight or whether some kind of Promethean leap will come to the rescue.
Introduction
In January, 2014, this journal published a Special Issue on "Oil and Gas Perspectives in the 21st Century". The Special Issue con- tained a paper by Robert Ayres and Vlasios Voudouris: "The eco- nomic growth enigma: Capital, labour and useful energy?" in which: they discussed the failure of neo-classical growth theory to take adequate account of energy and other natural resources; consideration of the concept of "useful energy"; and the in- adequacies of the first law of thermodynamics (which some have interpreted as energy cannot be wasted or destroyed, but only converted). Robert Solow is principally associated with the stan- dard neo-classical theory of economic growth, and here we con- sider his assumption that the growth theory need consider only two factors of production - labour and capital - against historic evidence and the realities of human existence. Admittedly, Solow in his famous paper on this subject began it by stating: "All theory depends on assumptions which are not quite true" ( Solow, 1956). The weakness of his case lies principally in his ignoring of energy and other natural resources because they contributed little to national accounts in monetary terms. The reality is that human existence and material progress have been heavily dependent upon the exploitation of natural resources, and particularly of energy, from the earliest times - not just since the Industrial Re- volution. Our ability to draw on larger and more concentrated supplies of useful energy (mainly from finite fossil fuel resources) has increasingly powered growth over the past 250 years, but the basic principles go back to the mists of time. A key question is: given the world's finite resources and limitations of renewable resources, how well is the human race positioned to cope with a human population anticipated to rise to nine billion by 2050, and possibly to over twelve billion by 2100?