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Sections 1-3
• Section 1: Global Change (The atmosphere & ecosystems/ Ozone Layer/ Global temps)
• Section 2: Effects on Ecosystems (Effects of Chemical Pollution/Loss of Resources/ Growth of Human Population)
• Section 3: Solving Environmental Problems (A Worldwide Effort/Solving Environmental Problems)
Global Change
• Human-induced environmental changes are affecting ecosystems worldwide
• Acid Rain: acidified precipitation-caused by coal-burning power plants that release sulfur into environment
The Ozone Layer• In 1985 Scientists
found that the ozone layer was depleted
• Decreased ozone allows more UV rays to reach the surface
• Increased rates of skin cancer, cataracts and cancer of the eye
What is Destroying the Ozone Layer?
• Chlorofluorocarbons (CFC’s) are the major destroying factor
• Found in coolants of refrigerators and air conditioners, in aerosol cans, and in foaming agents of styrofoam cups
Global Temperatures
• Since the 1950’s the average temperatures have been increasing (global warming)
• Greenhouse Effect: additional carbon dioxide in the atmosphere due to burning fossil fuels (CO2 traps heat)
Is Global Warming Occurring?
• There is a correlation between increasing CO2 levels and increasing temps
• This correlation does not prove cause/effect. This topic is a controversial subject among scientists
Effects on Ecosystems
• Chemical Pollution:ex dumping of industrial chemicals into Lake Erie
• Oil Spill in Alaska - injured/killed 1000s of animals
• Most incidents of pollution involve chemicals that are toxic or carcinogenic
Agricultural Chemicals• Pesticides,
herbicides, and fertilizers pollute areas around farms
• Agricultural chemicals pollute water sources and land
• DDT - pesticide that accumulates in fatty tissue of animals (Banned)
• Birds - thin eggshells
Loss of Resources
• Extinction of species- in last 50 years half of the world’s tropical rainforest have been burned down - 1000s of species are lost
• Loss of topsoil - excessive farming is causing topsoil to be lost
• Ground-Water Pollution/Depletion- aquifers are areas b/w porous rock that hold ground water
• Water is being removed faster than it is being replaced into the aquifer
Growth of Human Population
• Decreased death rates b/c of better sanitation and increased medical care
• World population annual increase is 94 million people
• Most industrial countries have lower rates of pop. increase (US/Japan/ Europe/New Zealand)
Solving Environmental Problems
• In 1990’s an international agreement stopped CFC production
• Many dangerous industrial and agricultural chemicals have been restricted in US
Reducing Pollution
• Sewage treatment plants remove chemicals/bacteria from sewage
• Scrubbers reduce sulfur emissions from smokestacks
• Carpool lanes to promote sharing rides
• The US has passed laws forbidding pollution
• All cars must have catalytic converters to reduce emissions
• Gas tax - extra money collected helps to rid pollution from air
Solving Environmental Problems
• 5 steps to success– Assessment - gather information, collect
data– Risk Analysis- scientists predict
consequences of different types of environmental intervention
– Public Education- present alternative actions, explain costs and results
– Political Action- politicians try to implement action
– Follow-through- monitoring of problem to see if problem is being solved.