Chapter 18

The Environment

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.

Your Contribution

• Conserve energy by walking, riding bike, or taking public trans

• Learn about your environment

• Reduce/Reuse/Recycle

• Create compost in your backyard