276 CLOUD 



our budget, as it were? The need to care for larger populations at better levels is 

 inevitable. The age structure of the present population is such that, even if we 

 were to begin reproducing at bare replacement from the present time,* the 

 population of the earth as a whole would increase by 50% in the span of a 

 human lifetime — that is, it would reach an eventual total of around 5.7 billion 

 earthians by about the year 2040, while the population of the United States 

 would still increase by about 35% over the same period of time, reaching an 

 ultimate population of around 280 million. No matter what we do, therefore, 

 short of going to the one-child or no-child family, we are going to have to care 

 for a larger population, and we want to care for these inevitably larger 

 populations at better levels of living. It does seem urgent to try to stretch the 

 limits of supportability along with taking ever greater precautions to safeguard 

 the environment and to limit population growth. 



Consider some of the ways in which the limits might be stretched. 



First, although overrated by many of its proponents, is nuclear energy. 

 Nuclear energy helps in three ways: 



1. It can lead to conservation of the fossil fuels that are really much too 

 useful as sources of plastics and other petrochemicals to be burned. The faster 

 we can move safely to deriving higher proportions of our energy budget from 

 nuclear sources, the less pressure that makes on fossil fuels, permitting them to 

 be conserved for other more versatile uses. 



2. Nuclear energy will bring distant resources to the market place, either by 

 lowering the costs of transportation or by making it possible, through the 

 transfer of energy to the mining sites, to beneficiate the products of the mine 

 locally and ship them to trade centers in the form of refined materials. 



3. Nuclear energy will probably make it possible to mine lower grades of 

 material more profitably than we are able to mine at the present time. But Fig. 7 

 shows how little correlation there has been between input of energy and mineral 

 productivity from 1870 until now. 



The application of nuclear energy to mining is usually visualized as involving 

 the fracturing of rock at depth by nuclear explosion, followed by the 

 introduction of leaching solutions or microorganisms to remove the metals and 

 bring them up to the surface. What has to be remembered in this kind of 

 operation, assuming that it can be carried off technologically, is that, first, the 

 rock has to be fractured to the particle size of the metals with which the 

 leaching solutions or microorganisms are to be brought in contact. Second, when 

 leaching solutions or bacteria are introduced, they may be lost to groundwaters, 

 contaminating the subsurface environment. Third, there is the problem of 

 keeping irradiated materials out of the environment and of keeping the product 

 itself from being irradiated so that it cannot be used. Thus a number of 



*End-of-1972 census reports indicate that we are currently doing this in the United 

 States — although global populations are still increasing 2% for a 30-year doubling time. 



