Presentation on theme: "CH08-1 Population Measuring its growth & impact ronmental%20Science/course%20files/multimedia/l esson35/animations/3b_Cultural_Carrying_Capacity.html."— Presentation transcript:
CH08-1 Population Measuring its growth & impact http://www.montereyinstitute.org/courses/AP%20Envi ronmental%20Science/course%20files/multimedia/l esson35/animations/3b_Cultural_Carrying_Capacity.html
CH08-2 The Growing Human Population The human population has grown slowly for most of human history. The rapid increase in population size is a relatively recent phenomenon.
CH08-4 Why Has the Human Population Grown So Large? The human population has skyrocketed in the last 200 years. Global decline of death rates without a decrease in birth rates. result of increases in food supply and better medicine and sanitation. Infant mortality in the U.S.
CH08-5 The Ecology of Expanding the Earth’s Carrying Capacity Technological advances lower environmental resistance promote population growth. Technology increases the carrying capacity for humans. Technology decreases the prospects of other species and may cause adverse effects in human populations as well.
CH08-6 What Is the Earth’s Carrying Capacity for Humans? Determining the Earth’s carrying capacity for humans is a task fraught with difficulty. Some people think we have not reached the carrying capacity. Others believe that the human population already exceeds the Earth’s long-term carrying capacity. Economics, Diet, & Culture
CH08-7 Too Many People, Reproducing Too Quickly Population is at the root of virtually all environmental problems pollution resource depletion social and economic problems environmental problems and solutions
CH08-8 Too Many People, Reproducing Too Quickly The massive size of the human population causes environmental problems evident in urban and rural areas. shortages of resources environmental deterioration a host of possible social problems
CH08-9 Reproducing Too Quickly Social, economic, and environmental problems of cities and rural areas are aggravated by rapid population growth. The large size of many populations makes it difficult for governments to keep up with current demands. Continued rapid growth makes it nearly impossible to improve conditions and create a sustainable human presence.
CH08-10 Fig. 8-4 Graph of global population growth
CH08-11 Understanding Populations and Population Growth Measuring Population Growth – Growth Rates and Death Rates Global population growth is determined by subtracting the crude death rate from the crude birth rate.
CH08-12 Doubling Time the time it takes a population to double in size. determined by dividing 70 by the growth rate. small growth rates can result in rapid doubling. Growth rates developed countries are relatively low. less developed nations, generally much higher.
CH08-14 The Total Fertility Rate and Replacement-Level Fertility Total fertility rate is the average number of children women are expected to have during their reproductive age span. Replacement-level fertility occurs when couples produce exactly the number of children needed to replace themselves. Zero population growth occurs when the death rate equals the birth rate and when the net migration is zero.
CH08-15 Migration The growth of a town, city, state, or region is determined by two factors: Growth rate (natural increase) Migration (the movement of people into and out of the population) Immigration, the movement of people from one region of a country to another, affects regional population growth.
CH08-16 Population Histograms Graphs of populations various age groups males and females provide useful information for planners. A countries histogram may be Expansive Constrictive Stationary Global population Expansive due to continued growth in the less developed nations
CH08-18 Exponential Growth Human populations are growing exponentially. Globally, the human population has “rounded the bend” of the exponential growth curve. This means that even small percentage increases result in huge numbers of new world residents.
CH08-19 Exponential Growth Exponential growth is cause for great concern. As our population increases, so do: our demand for resources our waste production our environmental damage
CH08-20 The Future of World Population: Some Projections and Concerns Predicting the future size of the world’s population is difficult. It is likely that the population of the world will increase dramatically before it stabilizes. This increase could bring about massive changes in the environment.
CH08-22 Population Growth in the Less Developed World: Why Should We Worry? Impacts: Social -- disease, war, equitable distribution of resources Economic -- education, available resources, sustainable development Environmental -- overuse of resources and pollution
CH08-23 A World of Possibilities The human population cannot grow indefinitely. Transition Options Smooth transition to a stable population size. Periodic crashes that will eliminate large numbers of people. Overshooting the carrying capacity destroy their ability to support people populations may fall to much lower levels.
CH08-24 Fig. 8-10 Patterns of population growth
CH08-26 A Bit of Good News… Population growth is slowing 1960 – Average family had 5 kids 2005 – Average family has 3 kids Sustainable – Average family has 2 kids (ZPG) 1994 – U.N. International Conference on Population & Development (ICPD) in Cairo, Egypt Multi-Faceted Approach Equity for Women – Education, Social, Political, Economic Economic Equity between rich and poor 2015 – affordable family planning and reproductive health care for all Sustainable Economic Development throughout the world