270 



ANNUAL REPORT SMITHSONIAN INSTITUTION, 195 



cultural degeneration this curve may decline, as in curve II, to the 

 subsistence level of our agrarian ancestors. 



Viewed on such a time scale, the curve of human population would 

 be flat and only slightly above zero for all preceding human history, 

 and then it, too, would be seen to rise abruptly and almost vertically 

 to a maximum value of several billion. Thereafter, depending largely 

 upon what energy supplies are available, it might stabilize at a maxi- 

 mum value, as in curve I, or more probably to a lower and more nearly 

 optimum value, as in curve II. However, should cultural degeneration 

 occur so that the available energy resources should not be utilized, the 

 human population would undoubtedly be reduced to a number appro- 

 riate to an agrarian existence, as in curve III. 



HUMAN AFFAIRS IN TIME PERSPECTIVE 



TIME (Thousonds of Yeors) 

 FiGUEE 8. 



These sharp breaks in all the foregoing curves can be ascribed quite 

 definitely, directly or indirectly, to the tapping of the large supplies 

 of energy stored up in the fossil fuels. The release of this energy is 

 a unidirectional and irreversible process. It can only happen once, 

 and the historical events associated with this release are necessarily 

 without precedent, and are intrinsically incapable of repetition. 



