IS THERE INTELLIGENT LIFE ON EARTH? 



271 



DIRECTION OF 

 ENERGY FLOW 



EXPLORATION 



MINING 

 EXTRACTION 



" M 'Ni NG ENGlN^ 



Fig. 3 Cycle of nonenergy materials in industrial society (inspired by a sketch 

 by A. G. Chynoweth). 



society — a strong multiplier effect on this quantity gradually upgrades it until it 

 represents a major fraction of all the goods and services utilized. Finally the 

 products, through various uses, deteriorate and become waste. This waste then 

 either becomes pollution, returning to or into the earth, or is recycled, bypassing 

 the raw-materials bottleneck and going back through the system again. One big 

 opportunity for improvement is in recycling, but remember that the quantities 

 needed are doubling every few decades or less because of exponential growth of 

 consumption. Therefore, even if everything is recycled, it is still necessary to 

 show at least as much new primary production for every doubling period. The 

 effects of some of those exponentially growing demands can be seen in Figs. 4 to 

 6. 



Figure 4 shows global reserves of selected critical raw materials compared 

 with demand expected to the end of the century. This information 

 is from the 4th edition of Mineral Facts and Problems, published by 



