13% 

 29% 

 33% 

 25% 

 60% 



If the 50-year percentage increases are plotted against 

 the dates, it appears that they indicate: (1) A rising 

 percentage increase in the average, from about 10% in 

 1650 to about 50% in 1950; and (2) a quasi-periodic 

 fluctuation in percentage increase, in a period of about 

 150 years. If this curve is extrapolated to 2050, the per- 

 centage increases in world population are given as about 

 75% for the 50-year period ending 2000 and about 

 45% for that ending 2050. With these values we can 

 calculate the approximate population numbers for 2000 

 and 2050 as being 4,200 million and 6,100 million re- 

 spectively. The figure for A.D. 2000 is considerably smaller 

 than the United Nations estimate of 6,300 million, which 

 figure would appear to be reached about A.D. 2050 ac- 

 cording to the present analysis. However, it seems rather 

 likely that by 2050 A.D. at the latest, the Earth's human 

 population will exceed 6,000 million, which corresponds 

 to more than 120 people per square mile, or about one 

 person per 5 acres of land, again assuming nearly all 

 the Earth's land to be made habitable. Since it is more 

 probable that, at most, about 40% of the land surface 

 could be made available for agriculture during the next 

 100 years, we may expect that about 2Vi acres of land 

 will be available, on the average, for each person living 

 in the year 2050 A.D. This should be adequate if it is 

 properly treated, but will necessitate a very large amount of 

 work in increasing the area of cultivated land from the 

 approximately 10% of total land surface now in agricul- 



63 



