Environmental Ethics PHIL 323 / INDS 323 The University of Arizona

World Human Population Numbers Research for this page was done by Elizabeth Willott and Amy Boomer (an undergraduate student in Env. Ethics, 1999). I. What is the world human population? Is this number reasonable? What doubt exists with this number? Where are errors introduced? How reasonable are projections into the future? The sources below give numbers but not error ranges and they do not discuss the basis of their projections. However, by looking at data pertinent to the world population numbers, we can get an idea of what drives their predictions. Note, however, that in 1955, it would have been impossible to predict that so many women would choose (or even have the option to choose) to practise birth control successfully. Projecting from now out to 2050 has difficulties because we don't know what changes are going to happen between now and then. See part III below for some links to relevant information. Some organizations giving figures on the world population, demographics, and changes include: US Bureau of the Census; UN Population; the World Bank; and The Union of Concerned Scientists. The latter site has some explanation of the projections made by the UN. 1950: 2.56 billion 1975: 4.09 billion 1995: 5.68 billion 2025: 7.9 billion projected 2050: 9.3 billion projected SOURCE: US Bureau of the Census. (World Health Report, 1998, agrees with these numbers) Shaded area includes projected figures. II. What accounts for the increase in world human population? Note that some of these are merely slightly different ways of looking at the same phenomenon. Sometimes seeing the same thing from different angles helps give a better insight. Life expectancy has been increasing: The US Census site gives the following: 1955: 48 years 1995: 65 years (World Bank says 67 for 1995) 2025 projected: 73 years (World Health Report, 1998, agrees with these numbers) Infant mortality rate per 1000 live births has been decreasing: 1955: 148 1995: 59 2025 projected: 29 years (World Health Report, 1998, agrees with these numbers) Child mortality (deaths of children under 5 years of age) has been decreasing (per 1000 live births): 1955: 210 1995: 78 2025 projected: 37 (World Health Report, 1998, agrees with these numbers) Fertility Rate, though dramatically decreased from 1955, still exceeds replacement level: 1955: 5 1995: 2.9 Worldwide, in 1995, the number of babies born per woman was 2.9 which is still above the replacement level of 2.1. However, contrast this with a rate of 5 in 1955. In all regions of the world, the fertility rate has been decreasing, often at an astonishing rate. This can account for the decline in the rate of increase in the world's population. The World Health Report, 1998, states that an extra 220,000 people accumulate each day. 365,000 babies born; 140,000 people die (US Census agrees) People are living longer before they die Infants and young children are much less likely to die now than 40 years ago. Many people are living longer and so the number of people dying at over 65 years of age has increased dramatically as a percentage of all deaths (compare 1955 with 1995) and is expected to increase even more by 2025. (World Health Report, 1998) People living longer contribute to the increase in world population. III. Predicting the Future Thirty years ago, it would not have been reasonable to predict the dramatic decline in the Fertility Rate (number of births per woman) that has occurred virtually worldwide (for more info see Fertility Rates). Nor could anyone have predicted the incredible decrease in child mortality or increase in rate of child vaccinations. Today we do not know what will happen in Africa as a result of the HIV-AIDS crisis. Sub-Saharan Africa contains approximately 13% of the world's population but has 67% of the world's HIV-AIDS cases. Many of the cases are infants. For more information about HIV-AIDS in Africa, visit the UNAIDS HomePage at http://www.unaids.org or visit the HIV-AIDS page at this site.

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