It is easy to understand the confusion of many concerning whether the world is overpopulated or under populated when one reads a news report on the increasing number of Sub-Saharan Africans followed by an article on the alarming lack of people in Russia or Eastern Europe. This confusion is due in part to the difference in population developments worldwide. A recently updated study by the Austrian-based International Institute for Applied Systems Analysis (IIASA) tries to explain the story of a continually diverging worldwide population, a population that is increasing in some areas and decreasing in others.
The study used the group’s 2001 study as its basis, adding new empirical data gathered since 2001. The new results say the total global numbers have not changed much since 2001; those areas with increased population growth offset those areas where the number of people is decreasing. This increased divergence in population growth and decline in specific areas will result in no change in the expected world population peak of about 9 billion people in about 2070.
According to IIASA, the populations of Eastern Europe, especially countries that were part of the former Soviet Union, are expected to decrease at a faster rate than was expected in 2001.
In many countries that were part of the former Soviet Union, the great political changes in the 1990s have “triggered a precipitous fertility decline, together with some mortality increase, particularly among men.” The areas already had a skewed age structure with many old and fewer young due to increased use of contraceptives and abortions and emigration, and with the expected continued decreased fertility and emigration, the IIASA report predicts that “[t]his has distorted the age structure to such an extent that even in the unlikely event of a return to replacement level fertility, there would be a population decline because fewer and fewer women are entering reproductive age.” This will cause future population shrinkage to increase exponentially with the expectation of the population size likely to decline to less than half what it is today by the end of the century.
That China is working hard to decrease its numbers is common knowledge. China’s population is expected to increase until the 2020s to around 1.5 billion and then decline as the age structure changes and the number of people of reproductive age decreases, The IIASA report concludes that “after an initial increase China’s population is likely to be back down to its 2000 level during the 2040s and then, by the end of the century, possibly almost down to half the 2000 level.”
Meanwhile the populations of sub-Saharan Africa are increasing faster than expected. This is due not only to stable birthrates, but also to a decrease in the estimated number expected to die from AIDS. This change in data is not due to medical progress or in stemming the spread of the disease, but to the UNAIDS’ inability to calculate numbers. As the IIASA report says, “This has less to do with the rapid spread of anti-retroviral treatment in parts of the continent than with a significant downward correction of the estimates made by UNAIDS of the numbers of people infected with the virus.”
The IIASA report expects Africa’s population to more than double in the future. As economic history has proven again and again, the economy grows where there are adequate people to fill the jobs. If the population of Africa continues to grow as the IIASA suggests, it is quite obvious where future economic development will be.
The IIASA report sees a problem demography watchers have long foreseen on the horizon: the inability of countries to stop the decreases in their populations. Once countries reach a replacement-level fertility, they do not even out and plateau. Instead, countries with decreasing birthrates find the populations continuing to decrease and countries with growing populations find their numbers continuing to increase: “But on a global level the demographic trends have seen little convergence over the past decades. In fact, over the past few years there has been outright divergence. Regions with already low fertility have seen further declines, and regions with high fertility have shown lower than expected declines. The high level of path dependency inherent in population growth has already produced a more heterogeneous demographic picture for the twenty-first century.”
See the Source: Prof. Wolfgang Lutz, Prof. Warren Sanderson, Dr. Sergei Scherbov, “The growing divergence in population trends and concerns,” Options, Winter 2007, http://www.iiasa.ac.at/Admin/INF/OPT/Winter07/opt07wint.pdf
