Populations/Urbanization. Ecology Field Study

Transcription

1 Populations/Urbanization Ecology Field Study

2 Earth s Population Why Worry?

3 Earth s Population Why Worry? What do you think the author of the cartoon (Tom Toles) is trying to say? Is the population of the planet an issue? Why or why not? Describe some ways that you can envision larger populations impacting the planet. Why should we care one way or the other about population?

4 Populations One of the largest problems facing the planet today is population growth. Numbers Beginning of the 20th century 2 billion people World Population 4/25/02 6,220,275,152 people World Population Today 1/20/10-6,797,615,020 people At the current rate of the growth, the human population doubles every 50 years.

5 Populations Effect on the Environment Many, if not all, environmental problems in the world today can be linked directly or indirectly to human impacts on the environment. The scope of the impacts increase with increasing population. Examples 1. 6 million acres of farmland (an area the size of Vermont) were lost between 1982 and million were due to urban growth and suburban sprawl. 2 million were lost to erosion, deforestation, and over use. 2. As human population increases the diversity and number of plants/animals decreases.

6 Populations Effect on the Environment 3. One or more entire species of plant or animal lost every 20 minutes 27,000 species /year This rate and scale of extinction has never occurred before. 4. Global emissions of CO2 have quadrupled since 1950 from deforestation and fossil fuel use. This contributes to global warming etc.

7 Population Growth Types Population growth occurs in two ways: 1. Exponential Growth population grows by doubling over given amounts of time. 2. Logistic Growth population grows to a certain point, and then levels off when it reaches the carrying capacity for the area in which it lives.

8 Carrying Capacity Carrying capacity is the maximum number of a population that a given habitat can support over a given period of time dependant on factors such as available resources and competition etc.

9 Real World Solutions to Controlling Population 1. Education 2. Empowering Women Access to family planning Improving health care for women and children Providing education opportunities Promoting male participation and education Eradicating violence against women Advocating for gender equity 3. Economic Development 4. Governmental Control Tax penalties Tax incentives Funding of education programs etc.

10 Transitional Stages of Economic Development and their Effects on Population 1. Preindustrial Hunter gather type of society Harsh living conditions High Birth Rate/High Infant Mortality/High Death Rate = Overall low population growth Overall low population growth 2. Transitional Industrialization Begins Food production rises (agriculture etc.) Health care improves Death Rates Drop Rapid population growth = 2.5% - 3% per year

11 Transitional Stages of Economic Development and their Effects on Population (Cont d) 3. Industrial Lots of industrialization Better education of population More opportunities for women (empowering women) Health care continues to improve Low infant mortality, lower birth rates Birth rates begin to approach death rates Population growth still occurs, but at a much slower pace Most developing countries are here, or entering this stage

12 4. Post Industrial Information society Birth rates continue to decline for reasons stated above Overall population slows to stop and begins to decline Emphasis shifts from unsustainable economic pursuits to more sustainable ones 37 countries including most of Western Europe are at this point. (Not US) Time is the key to moving past these transitions

13 Question How do we get developing countries through these various transitional stages without total degredation of the environment? How do we help them not to make the same mistakes and create the same problems that we did and have as we have moved on to a post industrial society?

14 Urbanization Urban Area Towns or cities plus their adjacent suburban fringe with populations of more than 2,500 people. Rural Area Cities or towns with populations less than 2,500. Urban Growth Rate of increase of urban populations. Growth rates vary developed countries/lesser developed countries

15 Reasons for Growth of Urban Areas Natural increases increase birth rates/decrease death rates Immigration usually from rural areas

16 People Pulled to Cities New jobs Higher income Education Culture Health care

17 People Pushed from rural areas Modernization of industry logging/farming etc. more machines, less people Less subsistence farming No land/jobs go to city for work Government services etc. Better Living

18 Environmental Pros/Cons of Urban Areas Pros Recycling Lower Birth Rates Educational Opportunities Concentrating people in one area reduces stress on wildlife habitat Concentrating people in one area reduces stress on wildlife habitat preserves biodiversity Cons Not self-sustaining Produce large quantities of waste Use large amounts of natural resources Disturb natural areas for resources decrease biodiversity Poverty becomes urbanized

19 Urban Pollution Problems Air Pollution Large numbers of people (1/5 pop) live in areas where pollution levels are above healthy levels. Autos/industry/wood burning etc. Larger issue in developing countries (lax laws) Issue in US due to volume Water Pollution Develop countries strict laws for water quality Lesser developed countries no money for treatment systems Sewage Treatment 90% of sewage in developing world discharged into lakes, oceans, streams etc.

20 Pollution Cont d Noise Pollution Urban dwellers subject to excessive noise Definition any unwanted disturbance or harmful sound that impairs or interferes with hearing, causes stress, or hampers work efficiency or causes accidents. Hearing loss, High blood pressure, headaches, insomnia Control by: Shielding noisy devices, shielding workers, noise cancellation, modify env. for less noise etc.

21 City Designs Three main types 1. Concentric circle model city develops outward from its central business district. (CBD industry poor more affluent suburbs) 2. Sector Model City grows out from CBD along transportation routes creates sectors 3. Multiple Nuclei Model City develops around a number of independent centers. Business, industry residential etc.