1. Unit 6 Part III: Human Environment Interaction
Stress on the Earth’s Landscape

2. I. Alteration of Ecosystems
From the beginning…fires, hunted, exterminated
Ecosystem-ecological units consisting of self-regulating associations of living and nonliving natural elements

3. II. Environmental Stress
A. Obvious Actions-cutting of forests, emission of pollutants
B. Less Obvious Actions-burying of toxic wastes, dumping garbage, use of pesticides
C. Concerns-future of water supplies, state of the atmosphere, climate change, desertification, deforestation, soil degradation, disposal of industrial wastes

4. Water
renewable resource, availability is not evenly distributed, most along equator
a. distribution is sustained through hydrologic cycle
b. aquifers-water-holding rocks/wells that distribute H20
Sign. 50x as much in aquifers as precipitation
c. water shortages –Africa, S. California, Spain

5. California Water Issues
80% water used for irrigation
Supply insufficient for population
Colorado River flow diminishing
Farmers are now digging for water to use for irrigation, putting pressure on ground (sinking)

6. The Aral Sea Once the 4th largest lake on earth.
Water diverted for Soviet Union cotton irrigation upstream on the Amu Darya and Syr Darya Rivers.
Watch the following video clip…

7. The Aral Sea

8. The Aral Sea

10. Politics and Water in the Middle East
Israel has one of the lowest natural renewable water resources in the world
½ of water supply comes from areas outside of Israeli state
Jordan River key source of water supply for Israel, along with aquifers beneath the West Bank
Desalinization is one of the ways in which Israel attempts to meet water demand throughout the state
Note: most water comes non-Israeli states

11. 80% of China’s rivers are unfit for human contact
80% of China’s rivers are unfit for human contact. Aquatic life in these rivers is in decline.

12. 40% of U.S. rivers, lakes, and streams are not fit for swimming, fishing, or drinking.

13. The Pacific Trash Vortex

14. Global Atmospheric Issues
The Ozone Hole
Global Warming
Acid Rain

15. The Greenhouse Effect
A normal climatic warming effect caused by permitting incoming solar radiation but inhibiting outgoing terrestrial radiation.
Three gases are the primary cause:
Carbon Dioxide (CO2)
Methane (CH4)
Water Vapor (H2O)
The effect is possible because outgoing earth radiation is of much longer wavelengths than incoming insulation.

16. Global Warming

17. The Global Warming Hypothesis
Human-induced rise in CO2 levels is causing unnatural warming of atmosphere.
Likely effects:
Increased storminess
Rising sea level (.2-1 meter in 100 years – IPCC, 2001)
Loss of arable land (some areas hotter, others cooler)
Extinction of thousands of species
Loss of nearly all coral reef
Millions of climate refugees
Loss of Arctic sea ice during summer

18. Acid Rain
Burning fossil fuels-emission of sulfur dioxide and nitrogen oxide Leads to acidification of lakes and streams, stunted growth of forests, loss of crops

19. The Land
I. Deforestation-44% of tropical rainforests had been cut down in the 1980s; predictions that all rainforests will be gone in less than 90 years; second-growth forests uninhabitable by most animal species
II. Soil Erosion-pressures on land to produce more; 37,000 acres lost each year to livestock, wind erosion, dry climate
III. Waste Disposal-U.S. largest producer of solid waste (3.7 lbs./person/day); open vs. sanitary landfills; suitable land for landfills decreasing; toxic (chemicals) vs. radioactive (low vs. high radiation)

20. Loss of Biodiversity
U.N.’s Environmental Program’s Global Diversity Assessment indicates 8% of plants, 5% of fish, 11% of birds, and 18% of the world’s mammal species are currently threatened.
*Species on islands are particularly susceptible to extinction. Why?

21. Discussion
Who is ultimately responsible for environmental degradation?
What should be done to improve environmental conditions that have resulted?
Does sub-Saharan Africa play a role in any of this? Why or why not?
What can be done to improve the development of Sub-Saharan Africa? Do they even have any hope?