Global Estimates and Projections of World Populations. Relation between Hypothesis, Theories and Policies.

The United Nations 2002 Revision of the world population projections has radically reviewed the results of the preceding revision. The results obtained show that it is reasonalbe revision. The results obtained show that it is reasonable to dispel the fear of an excessive and perhaps uncontrolled growth of world population, which alarmed public opinion and many international organizations in the last decades. Even in the medium variant, by the year 2050 world population will be less than 9 billion, with zero growth. In view of the fact that fertility will remain below replacement level, after that a process of slow decrease might set in, despite a further sharp increase in survival rates. The objectives of the projections are of an administrative nature: firstly, to adapt global and local policies to the real needs of the population; secondly, to distinguish the trends that are favourable or harmful for the population's greater wel-being; thirdly, to govern society in such a way as to achieve the highest possible standard of living, which must be extended to everyone, long-lasting, and therefore compatible with the limits imposed by the environment; the final objective is not to subtract resources from the future generations. The hypotheses formulated are based on interpretations of past data, on assumptions and theories not shared by all demographers. In various instances, they have proven to be erroneous in retrospect. Also the policies promoted by international organisms and enforced in various states are founded on theories which are often controversial. They have ethical aims, but they are often contested in the name of personal freedom. As the real evolution of world populations is different from what had been hypothesized, desired and programmed, it follows that certain scientific and political errors have been made. The most evident indicator is the increase in the differences in wealth and lifestyle among the various nations.