ENERGY FROM FOSSIL FUELS — HUBBERT 257 



conquest of a larger and larger fraction of the available energy. The 

 invention of clothing, the use of weapons, the control of fire, the do- 

 mestication of animals and plants, and many other similar develop- 

 ments all had this in common: They increased the fraction of solar 

 energy available to the use of the human species, and they continuously 

 upset the ecologic balance in favor of an increase in numbers of the 

 human species, v^ith corresponding adjustments in all the other popu- 

 lations of the complex of which the human species was a member. 



From that early beginning until the present day this progression 

 has continued at an accelerated rate. It has involved the development 

 of wind power and water power, the smelting of metals with wood as 

 fuel, the extensive employment of beasts of burden. However, 

 throughout this period until within the last few centuries the rate of 

 these changes has been small enough for population growth to keep 

 pace. The energy consumed per capita, therefore, has increased but 

 slightly. 



ENERGY FROM FOSSIL FUELS 



Emancipation from this dependence upon contemporary solar en- 

 ergy was not possible until some other and hitherto unknown source 

 of energy should become available. This had its beginning about the 

 thirteenth century when some of the inhabitants of Britain made the 

 discovery that certain black rocks found along the shore of the east 

 coast, and thereafter known as "sea coles," would burn. From this 

 discovery there followed in almost inevitable succession the mining of 

 coal and its use for the smelting of metals, the development of the 

 steam engine, the locomotive, the steamship, and steam-electric power. 



This development was further augmented when, about a century 

 ago, the second large source of fossil energy — petroleum and natural 

 gas — was tapped, leading to the internal-combustion engine, the auto- 

 mobile, the airplane, and Diesel-electric power. 



A third source of fossil energy, oil shale, although exploited on a 

 small scale for almost a century, is only now approaching its phase 

 of rapid development. 



RATES OF PRODUCTION 



It is to the rate of increase and the magnitude of the consumption 

 of the energy from fossil fuels that I now wish to direct your attention. 



Consider coal. Although production statistics for the earlier peri- 

 ods are not available, it is known that from the initial discovery and 

 use of "sea coles" to the present there has been a continuous increase in 

 the rate of consumption of this commodity. During the eighteenth 

 century the need for power for the coal mines led to the development 

 of the steam engine, and the demand for better means of transporta- 

 tion led first to the railroad and then to the steam locomotive. We 



