1. Chapter 18 The Environment Section 1 – Global Change Section 2 – Effects on Ecosystems Section 3 – Solving Environmental Problems

2. Acid Rain  Acidified precipitation caused by nitric and sulfur-rich air pollution  Burning fossil fuels  Sulfur and nitric acid in atmosphere combined with water vapor falls to Earth and joins the water cycle  How acidic is the precipitation?  Drops the pH from 7.0 to 4.0-4.5  What is the impact of acid rain?

3. Effects of Acid Rain  Largest affect is on aquatic ecosystems  High levels of nitric and sulfuric acid are toxic to organism  Toxicity can affect all organisms in a food chain from producers to large predators  The soils of nearby areas can become too acidic and plants start to become vulnerable to death if they cannot adapt to the new pH

4. Pesticides  Chlorinated hydrocarbons broken down  The process is slow and the toxins accumulate in fatty tissues of animals  Biological Magnification: Molecules move up the food chain as organisms are consumed  DDT  Now banned due its threat to the bird population in 1972

5. Ozone Layer  A protective, upper layer of the atmosphere that reduces the amount of UV rays that hit the Earth’s surface  Ozone Hole  The concentration of O 3 is lower over Antarctica  Expected to have started becoming less concentrated from 1978 and on  Decrease in concentration has led to more UV exposure and diseases

6. Causes of the Ozone Hole  Main cause: Chlorofluorocarbons (CFCs)  Chlorofluorocarbons (CFCs)  Created in 1920s as stable and harmless coolants  Present in fridges, Styrofoam, air conditioners and aerosol cans  Presently banned in the US  Began escaping into the atmosphere breaking down the O 3  Cl bonds reacted with oxygen – producing less O 3

8. Global Temperatures  Temperatures have a typical pattern of increase then decrease for about a century  Effected by sunspot cycles  Since 1950’s the temperatures have only been increasing  Global Warming Periods of steady increase usually followed by cold periods  Human activities have contributed to larger cycles of global warming

10. The Greenhouse Effect  Greenhouse Gases Water vapor, carbon dioxide, methane and nitrous oxide  These gases insulate the planet  The Greenhouse Effect Bonds in carbon dioxide absorb heat radiating off the Earth and this heat is trapped by the atmosphere  As carbon dioxide levels increase, more heat is being absorbed by the atmosphere

11. Loss of Resources  Nonrenewable resources are being used at faster rates – leaving a path of destruction in its wake  Effects of Loss of Resources  Extinction of species  Loss of Topsoil  Ground-water Pollution and Depletion

12. Extinction of Species  Human activities like cutting down parts of rainforests are leading to the next mass extinction  Approximately 10% of the species are subject to extinction  The worst possible outcome is loss of over 1/5 th of the rainforests species  The loss of species can affect not only the ecosystem, but the possible benefit of those species to human kind.

13. Loss of Topsoil  Replacement of topsoil is impossible – about a centimeter is lost every year  The causes are from turning the soil to eliminate weeds, overgrazing and poor agricultural practices  These methods cause water and wind to remove soil from the area  Since 1950 – 1/3 rd of the topsoil has been lost

14. Ground-water Pollution and Depletion  Aquifers Porous rock reservoirs that hold ground water  Ground-water is a precious resource that is being used by the buckets at rates that are too large for consumption  Another portion of ground water is being polluted by chemical wastes  Removing of wastes is impossible

15. Growth of the Human Population  Fundamental causes of destruction  Average Global birth rate = 1,000/year  Average death = 9 per 1,000/ year  Population exceed 6 million in 1999  US rate is declining  Third world countries increasing  Projected stable 9.7 million by 2050  Will our resources support us until then?

16. Worldwide Effort  Began in 1990s  First Problem: Pollution  International consensus decided to reduce or eliminate use of CFCs  US started a ban DDT  Some countries followed suit  Sewage treatment plants  Scrubbers – smoke stacks  Reduce car use – eco-friendly cars

17. United States Effort  Pollution Effective Efforts  Laws Forbidding Pollution  Strict standards about what is released into the atmosphere  Clean Air Act of 1990  Pollution Tax  To be effective the tax amount must equal the cost of the pollution  Gas tax is most popular

18. Five Steps to Success  Assessment  Using data and observations – scientists make ecosystem models  Risk Analysis  Models are used as a trial and error system  Plug in a disruption and understand the consequence  Formulate a solution and check possible progress

19. Five Steps to Success  Public Education  Informing the main cause of the problem of possible alternatives  Also can use the public for ideas  Political Action  Power of persuasion and a group of followers  Follow-Through  Collect data over time to evaluate the progress and report to public

20. The Nashua River (New England)  Problem: Polluted by mills starting in 1900s  Solution (1966): Marion Stoddart and politicians start a group to finance a water treatment plant Industrial dumping is now banned  Progress: As of 1990, the river has recovered and abilities to swim are intact

22. Lake Washington (Seattle)  Problem: Water treatment plan discharge into the lake between 1940 to 1953 Blue-green algae started to grow with the new presence of nutrients  Solution: In order to clean-up the lake, taxes financed trunk sewers that divert sewage to Puget Sound  Progress: As 1961, clean bill of health and full of life

23. Lake Erie Algal blooms

24. What Can You Do?  Conserve energy by walking to locations, use public transportation or carpool  Energy inventory at home  Educate yourself about the environment  Recycle and upcycle  Compost