Download Name: Chapter 1: Environmental Science: A Global Perspective

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Chapter 1: Environmental Science: A Global Perspective
Section 1.1: Understanding Our Environment
• Environmental Science is a relatively new field
• It is the study of how humans interact with the environment
• Major focus is solving environmental problems
• The term ‘environment’ refers to everything that surrounds us
• Our environment includes natural world as well as things produced by humans
Solving Environmental Problems
• 40 years ago, people did not think much about the environment
• After WWII, people moved out of the crowded cities to the suburbs; rapidly expanding industries made
jobs plentiful; bigger cars and household electric appliances made life more comfortable
• Have we paid the price over the years for that comfortable lifestyle? Rivers/lakes are too polluted to
enjoy; air pollution hangs over cities; increased health risks from chemicals in the water, soil and food;
no place to put our trash
• Environmental problems can be complicated; preventing pollution can be expensive; cleaning it up can
be even more expensive
• Environmental problems can be solved
• Our environmental problems are huge and require careful attention and action
• The 21st century is a crucial time in human history; a time to find solutions that will allow people all
over our planet to live in clean, healthy environments and have all the resources they need for a good
life
What are our main Environmental Problems?
• There are unlimited numbers of environmental problems facing us today: whether to ban septic tanks,
where to build landfills, ozone advisories, making decisions based on rare birds or insects, etc.
• Almost all environmental problems fall into one of three categories: resource depletion, pollution and
extinction
Resource Depletion
• A resource is depleted when a large part of it has been used up
• Natural resource – any natural substance that living things use (sunlight, air, water, soil, minerals,
plants, animals, forests, fossil fuels
• Nonrenewable resources – resources that cannot be replaced (fossil fuels like oil, natural gas); when
they are used up, they are gone
• Renewable resources – resources that are continually replaced (solar, trees, fish, wind); can be
depleted if used up faster than it can be replaced, ex: trees
Pollution
• Introduction of harmful levels of chemicals or waste material into the environment
• Heat energy and nitrous oxide are by-products of fuel combustion
• Pesticides are intentionally created for practical reasons but cause a great deal of harm to water, air
and soil
• Pollutants also are dangerous to humans, ex: Mercury (in water) can cause nerve damage in humans
when they eat contaminated fish
Extinction
• Extinction means that the last of a species has died and will never be seen again
• Thousands of species are becoming extinct every year—some have never been identified, named or
studied; more today than any other time in history
• Extinction is one of the most significant challenges we face today; most species are dying as a result of
the loss of habitat
A Global Perspective
• Most environmental problems are global
• Sulfur dioxide released by coal-fired electric generators in Midwest come back as acid rain in Canada;
cars release carbon dioxide in the atmosphere, causing changes in the atmosphere; rainforest
destruction also increases CO2 in the atmosphere; CFC’s produced all over the world harm the ozone
• Biosphere (extends 8 km or 5 miles) above and below the surface of Earth; all living things exist in this
space with the non living things necessary for survival
Developed and Developing Countries
 Even though all humans live in biosphere; different countries have different needs and priorities
 Countries can be categorized into two groups:
 Developed – highly industrialized, high average incomes; ex: USA, Canada, Japan, Australia, New
Zealand, western Europe
 Developing – less industrialized, low average incomes, for instance, average farmer in India makes only
$2700/yr., Kenya $450/yr.; not all are this poor, come countries like Malaysia, Mexico and Thailand are
rapidly growing
Population and Consumption

Many of our environmental issues are linked to increasing human populations and increase needs of
our natural resources

Population crisis – some regions of Earth have human population increasing more rapidly than the
natural resources can support; most severe in developing countries where they already don’t have
enough resources; too many people and there are not enough natural resources for people to live
healthy and productive lives: malnutrition, starvation and disease are constant threats

Consumption crisis - when resources are polluted, used up or wasted, the resources are used faster
than they can be replaced, renewed or cleaned up; most severe in developed countries where
population is stable or growing slowly, but citizens use more than their share of the resources (USA);
developed countries used up 75% of resources but make up only 20% of world’s population
A Sustainable World

Goal of environmental problem solving is to achieve a sustainable world – a place where humans can
exist indefinitely with high standards of living and health, habitats preserved and garbage turned into
harmless substances

Nonrenewable resources would be used sparingly

Renewable would be used only as fast as it could be replaced