Overpopulation• ~7 billion people• Many natural

resources are nonrenewable

• More people means:– 1) More forests

removed– 2) More resources

consumed– 3) More pollution

• Nonrenewable resources = used faster than they can form or be replenished:– Coal– Oil– Natural Gas

• Renewable resources = cannot be used up or can replenish themselves over time :– Wind– Solar– Water

Fossilfuels

The Greenhouse Effect• G.H.E. is naturally good

(it warms Earth)• Problem: Excess heat

trapped near the earth’s surface

• Fear: Climate patterns change, ice caps melt

• Main Cause: CO2 from burning of fossil fuels

• Solutions: Reduce use of fossil fuels, regrow trees, alternative energy sources

What’s a Greenhouse?A Greenhouse is designed to trap heat so you can grow plants year round, even in cooler environments.

heat

heat

heat

heat

Some heat escapes the greenhouse, but enough is trapped to keep the inside warm

Earth

heat

heat

heat

Some heat escapes into space

Some heat naturally trapped by Earth’s atmosphere

The Natural Greenhouse Effect is good!

The Atmosphere

CO2, Methane, other greenhouse gases

Earth

heat

heat

heatheat

heat

Excess CO2 in atmosphere

Less heat escapes into space

More heat trapped near Earth’s surface

The Greenhouse Effect is naturally GOOD!

Mars: No Greenhouse Effect

Little heat is trapped by the thin CO2 atmosphere. High temperatures can be around 20⁰F.

Earth: Balanced Greenhouse Effect

Average global temperature is 57⁰F.

Venus: The Extreme Greenhouse Effect

Heat is trapped by the thick CO2 atmosphere. Temperatures reach 750⁰F.

• Defined: Precipitation with a below normal pH

• Cause:– Pollution from burning

fossil fuels rises into the air

• Effect:– Ecosystems more acidic– Kills plant and animal life– Biomagnification: toxins

accumulate in living tissue higher up the food chain

• Solutions:– Reduce fossil fuel usage– Add buffer (base) to

waterways

Biomagnification

Acid rain

Pesticide runoff

Fertilizer runoff

Mercury

SO2

NO

NO

Nitric acid

Sulfuric acid

Ozone Layer Depletion• Ozone Function: Block

UV radiation from sun• Problems:

– CFCs thinning the ozone layer

• CFCs common to coolants and foam production

– More UV radiation reaches the surface

• Effects: Crop damage, skin cancers, Eye damage

• Solution: Reduce CFCs, regrow trees

UV

Ozone layer blocks UV radiation from the sunOzone layer

CFCs

UV

Argh!!!!

The Smog and Ground-Level Ozone• Reason:

– Burning of fossil fuels & industry

• Problems:– Respiratory illness– Ozone gas is poisonous

• Causes:– Particulates rise into air

and react with sunlight to make air pollution

• Solutions:– Reduce use of fossil fuels– alternative energy sources– Plant trees

When is ozone good vs. bad?

When Good

• When 10-30 miles up in the atmosphere

• It blocks UV radiation from the sun

• Life doesn’t exist in the stratosphere

When Bad

• When near the ground• Where life exists

Deforestation • Defined: Clearing of forested areas

• Reasons:– High demand for wood– Create farmland

• Problems:– Species extinction– Excess CO2 released– Desertification: wind/rain

carry soil away

• Solutions:– Recycle– Improved farming

techniques

Non-native Species Introduction• Defined: Foreign organisms

are introduced to a new habitat• Reason:

– Pet industry, “free ride” organisms, pest control

• Effects:– Foreign species outcompete

native species– Food webs unbalanced– Decrease biodiversity– Economic damage

• Solutions:– Laws preventing foreign

goods into new countries

Kobe Kuiz1) CFCs are manmade chemical responsible for the destruction of

_________________.

2) Which gas is a main contributor to the greenhouse effect?

3) Crop damage and cancers are caused by an excess amount of which type of energy?

4) Name the big three fossil fuels.

5) Which planet has excess temperatures because of a thick CO2 atmosphere?

6) Desert-like land is created as a result of which problem?

7) Where is ozone gas harmful to life?

8) Where is ozone gas helpful to life?

9) Food webs become unbalanced as a result of the introduction of which type of organisms?

10) Even though there may be space for people, why do those who study the environment consider humans to be overpopulated?