Why does comparing the total population
of two countries not give us enough
information about the population situation?
Answers
Answer:
Government policymakers and planners around the world use population projections to gauge future demand for food, water, energy, and services, and to forecast future demographic characteristics. Population projections can alert policymakers to major trends that may affect economic development and help policymakers craft policies that can be adapted for various projection scenarios.
The accuracy of population projections has been attracting more attention, driven by concerns about the possible long-term effects of aging, HIV/AIDS, and other demographic trends. The National Research Council of the U.S. National Academy of Sciences (NAS) convened a panel of experts in 1998 to examine the assumptions, accuracy, and uncertainty related to the most widely used population projections and to recommend ways to improve these projections. After extensive review, the panel concluded in July 2000 that current world population projections to the year 2050 are based on sound scientific evidence and provide plausible forecasts of demographic trends for the world. The panel cautioned, however, that projections for specific countries, for certain population groups, or for longer periods in the future are less certain than global and shorter-range projections.
Comparison
World Population > Explanation
Populations can be compared in many ways, for example changing world and national populations across time, differences between national populations and differences between groups (for example, ethnic groups) within a national population
World Population > Growth & Decline
When talking about population it is necessary to consider both population growth, and population decline. Take a look at the graphs below. What causes the types of changes seen in these two graphs?
World Population > Fertility
Fertility is usually measured by the Total Fertility Rate.
World Population > Mortality
Changes in the death rate also influence population growth. The expected mortality rate of any given cohort (people born in the same time period) is measured by Life Expectancy, the number of additional years of expected life for all those born in a given year.
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