FORECAST OF WORLD POPULATION
The future of world population could be significantly affected by the worldwide HIV/AIDS pandemic. In Africa, birth rates are already the highest in the world, especially in Sub-Sahara Africa. But if HIV/AIDS is controlled or even eradicated, world population could increase much faster than predicted.
In the long run, the future population growth of the world is difficult to predict. Birth rates are declining slightly on average, but vary greatly between developed countries (where birth rates are often at or below replacement levels), developing countries, and different ethnicities. Death rates can change unexpectedly due to disease, wars and catastrophes, or advances in medicine. The UN itself has issued multiple projections of future world population, based on different assumptions. Over the last 10 years, the UN had consistently revised these projections downward, until the 2006 revision issued March 14, 2007 revised the 2050 mid range estimate upwards by 273 million.
Alternately, the United States Census Bureau issued a revised forecast for world population that increased its projection for the year 2050 to above 9.4 billion people (which was the UN''s 1996 projection for 2050), up from 9.1 billion people. The latest Census Bureau estimates for the same upcoming years are as follows. Predictions based on our growing population
In 1798, Thomas Malthus incorrectly predicted that population growth would eventually outrun food supply in the middle of the 19th century, resulting in catastrophe. In 1968, Paul R. Ehrlich reignited this argument with his book The Population Bomb, which helped give the issue significant attention throughout the 1960s and 1970s. The dire predictions of Ehrlich and other neo-Malthusians were vigorously challenged by a number of economists, notably Julian Simon.
On the opposite end of the spectrum there are a number of people who argue that today''s low fertility rates in Europe, North America and Australia, combined with mass immigration, will have severe negative consequences for these countries.
Child poverty has been linked to people having children before they have the means to care for them. More recently, some scholars have put forward the Doomsday argument applying Bayesian probability to world population to argue that the end of humanity will come sooner than we usually think.
It should be noted that between 1950 and 1984, as the Green Revolution transformed agriculture around the globe, world grain production increased by 250%. The energy for the Green Revolution was provided by fossil fuels in the form of fertilizers (natural gas), pesticides (oil), and hydrocarbon fueled irrigation. The peaking of world hydrocarbon production (Peak oil) may test Malthus and Ehrlich critics.
The world population has grown by about four billion since the beginning of the Green Revolution and most believe that, without the Revolution, there would be greater famine and malnutrition than the UN presently documents (approximately 850 million people suffering from chronic malnutrition in 2005).
Demographics of youth
According to the 2006 CIA World Fact book, 27.4% of the world''s population is below 15 years of age.
Before adding mortality rates, the 1990s saw the greatest number of raw births worldwide, especially in the years after 1995, despite the fact that the birth rate was not as high as in the 1960s. In fact, because of the 160 million-per-year raw births after 1995, the time it tookach the next billion reached its fastest pace (only 12 years), as world population reached 6 billion people in 1999, when at the beginning of the decade, the reaching was designated for the year 2000, by most demographers. People aged 7 through 17 make up these births, today.
1985–1990 marked the period with the fastest yearly population change in world history. Even though the early 1960s had a greater growth rate than in the mid and late 1980s, the population change hovered around 83 million people in the five-year period, with an all-time growth change of nearly 88 million in 1990. The reason is because the world''s population was greater in the mid and late 1980s (around 5 billion) than in the early 1960s (around 3 billion), which meant that the growth rate in the ''80s was no factor on the dramatic population change. People aged 17 to 22 make up these births, today.