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What is the history and projected future of human population growth? What impacts does human population growth have on ecosystems and human health? How is the population problem being addressed through public policy? Birth and Death Rates Balance Population growth is offset by death. Population size stabilizes when birth and death rates are equal and low. As an area develops, death rates drop Birth rate varies across the globe Carrying Capacity The carrying capacity of an ecosystem is the size of the population or community that can be supported indefinitely on the available resources and services of that ecosystem. Unlimited Population Growth Population Time interval Without limits, populations increase geometrically (2, 4, 8, 16, 32, 64, 128, 256, 512, 1024, 2048, 4096, etc) Population Growth Varies in Different Parts of the World Population in billions Population is growing rapidly in some regions and slowly in others. Human Population Growth Rates Human populations are growing more slowly. World Population But human population is still increasing. Just over 6 billion now, 9 billion by 2050. World Population But human population is still increasing. Over 6 billion now, (6,625,022,006) 9 billion by 2050. Urbanization is a Worldwide Issue More people are living in cities and fewer are living in rural areas. Africa - Water Supply Water Supply will be critical in many areas by 2050. Projections for Worldwide Water Supply
NOW in the world: 20% lack safe drink water 50% lack sanitation By 2025 the US, Europe, and much of Asia are expected to be experiencing moderate to high water stress (using more than 20% of available each year). Africa - Food Supply Increasing human population has directly caused degradation of agricultural land and a drop in per capita (per person) food production in fast growing developing countries. Europe and Central Asia Overexploitation of Resources "Stocks of commercially exploited fish are in serious condition... the North Sea fishing fleet should be reduced by 40 percent to match available fish resources."
UNEP, Global Environmental Outlook 2000 West Asia - Land Degradation
Arable (farmable) land per capita The amount of arable land is decreasing rapidly.
Source: data compiled by UNEP GRID Geneva from FAOSTAT 1997 North America - Excessive Energy Use
Energy use per capita (per person) Americans use more energy than any other country in the world. Most of this energy is in the form of fossil fuels.
Source: compiled by UNEP GRID Geneva from WRI, UNEP, UNDP and WB 1998 North America - Excessive Emission of Greenhouse Gases
CO2 Emissions per capita (per person) The United States is the world leader in the production of greenhouse gases.
Source: compiled by UNEP GRID Geneva from WRI, UNEP, UNDP and WB 1998 Summary of Projected Population Growth Population increase per year Industrialized countries - population growth is slowing and will eventually fall below replacement. Developing nations - population growth will peak and then decrease, but will remain very high. It is clear that overpopulation can lead to environmental problems and decrease the quality of life for people in crowded areas. What is being done about it?
The last 30 years have seen an increase in government supported family planning efforts around the world.
A history of family planning policies. Policy Objectives of Existing Family Planning Programs
1. Reducing fertility rates and slowing population growth benefits developing nations. 2. Family planning mitigates (minimizes) the adverse health consequences of high fertility for mothers and their children. 3. Individuals and families have the right to control reproductive decisions, including family size and the timing of births.
International Family Planning Programs: Criticisms and Responses, RAND, 2000 Policy Objective 1. Reducing fertility rates and slowing population growth benefit developing nations. Criticism: Family planning programs are not an effective way to reduce fertility or slow population growth. Response: Data do not support this criticism. Voluntary family planning is effective in reducing fertility. The existence of family planning programs leads to an increase in contraceptive use. Policy Objective 2. Family planning mitigates (minimizes) the adverse health consequences of high fertility for mothers and their children.
Criticism: Family planning programs promote abortion or increase it's likelihood. Response: The most well-documented data do not support this criticism. In Bangladesh and the former Soviet Union, family planning reduced abortions by reducing unwanted pregnancies. Data show that some women will end a pregnancy through abortion whether it is legal or not. Policy Objective 3. Individuals and families have the right to control reproductive decisions, including family size and the timing of births.
Criticism: Family planning programs can be coercive and ignore basic principles of voluntarism and individual welfare and rights. Response: Yes, this has happened in some instances. China's 1 child per family law - led to forced abortions, forces sterilizations, and female infanticide 1998 - US Congress passed the Tiahrt Amendment, which emphasizes USAID's commitment to voluntarism and informed choice in family planning Even if population growth slows, population will continue to increase. In developing countries, most of the population is young and will continue to have children. Population growth will slow quickly in developed countries, because most of the population is old. ...
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This note was uploaded on 05/18/2008 for the course BIO 105 taught by Professor Adler,irschick,podos during the Fall '08 term at UMass (Amherst).
- Fall '08