the high/medium variant projections are considered to be more realistic. If that is the case, the world population in 2150 is 20.8 billion and some increase for years after is inevitable. Then, the next problem will be whether there are enough supporting resources for the world population to support more than 20 billion people. This will be discussed in the next section.
By the way, Figure 1 indicates long-term projections for the world population growth rate. From prehistoric age to the present, its characteristic is that up till the 18th century, the population growth rate had been always quite low. If U.N. projections are correct and world population growth stays as low in the future, then it means throughout several million years of history of mankind, it was only for a short time, which is less than a hundred years from between 20th century to the first half of 21st century, when population growth rate exceeded 1%. Therefore, it means that those who received life in the present time are blessed with the supreme opportunity to live in such a precious age and to witness the most dramatic change in the history of population.
5. Carrying Capacity of the Earth
How many people can the earth support? This is an old yet new problem. According to "How many People Can the Earth Support?" (W.W. Norton & Company, 1995) which was written by Cohen (Joel E. Cohen) recently, the first man who figured out the supporting resources for the world population was a Dutch man, named Leeuwenhoek who was known as the inventor of the microscope, and in 1679, he figured it out the number of 13.4 billion. This was obtained by multiplying the population density of Netherlands, which was the highest in the world in those days, by area of surface of the earthwhich is livable. However, it is interesting to see that today, more than 300 years after his time, world population projections made recently by the U.N. and Bank of World projected (U.N. for 11.5 billion, & Bank of World for 11.4 billion) world population of the middle of 22nd century which is in the stabilized
