Fixing a Hole in the Sky

•Ozone is a naturally occurring molecule that absorbs
and redirects harmful UV radiation.
•In the 1970s, Mario Molina and Sherwood Rowland
discovered that CFCs were rapidly destroying ozone in
the stratosphere.
•Today, most nations have banned CFCs, and the ozone
hole is expected to close up around 2050.

Talk About ItShould environmental scientists’
discoveries about the natural world influence human
activity? If so, how?

What Is Environmental Science?

• The study of our planet’s natural systems and how

humans and the environment affect one another

• The environment includes all living and nonliving things

with which organisms interact.

• Understanding the interactions between humans and

the environment is the first step to solving
environmental problems.

Lesson 1.1 Our Island, Earth

Environmental Science vs.

Environmentalism

• Environmental Science: Objective, unbiased

pursuit of knowledge about the workings of the
environment and our interactions with it

• Environmentalism: Social movement dedicated to

protecting the natural world

Lesson 1.1 Our Island, Earth

Natural Resources

• Natural resources are materials and energy sources found in nature that

humans need to survive.

• Renewable resources: Naturally replenished over short periods
• Nonrenewable resources: Naturally formed more slowly than we use them.
• Renewable resources can become nonrenewable if they are used faster than

they are replenished.

Lesson 1.1 Our Island, Earth

Human Population Growth

• Tremendous and rapid

human population growth
can be attributed to:

• The Agricultural

Revolution: About 10,000
years ago; humans began
living in villages, had longer
life spans, and more
surviving children.

• Industrial Revolution:

Began in early 1700s; driven
by fossil fuels and
technological advances

Lesson 1.1 Our Island, Earth

Did You Know? The human population
increases by about 200,000 people every day.

Ecological Footprints

Lesson 1.1 Our Island, Earth

•The total amount of land and water required to:

• provide the raw materials an individual or population

consumes

• dispose of or recycle the waste an individual or

population consumes

•Most informative when footprints are calculated
using the same method

Did You Know? By one calculation, the
ecological footprint of the average American is
3.5 times the global average.

Tragedy of the Commons

• Describes a situation in which resources, made

available to everyone, are used unsustainably and
eventually depleted

• Resource management, whether voluntary or

mandated, can help avoid resource depletion.

Lesson 1.1 Our Island, Earth