Greenhouse Effect CO 2 Earth as a Closed System

Earth as a Closed SystemEarth as a Closed System

The Earth’s Atmosphere

• 78% Nitrogen• 20% Oxygen• 1% Argon

• 0.03% CO2

• Trace Elements

‘The Precious Envelope’

Helium

NitrogenOxygen

Watervapor

Argon

Neon

Carbondioxide

Air

Copyright © 2007 Pearson Benjamin Cummings. All rights reserved.

Component Percent composition

Nitrogen, N2 78%Oxygen, O2 21%Argon, Ar 0.9%Water, H2O 0 – 4% (variable)Carbon dioxide, CO2 0.034% (variable)

The Earth’s AtmosphereFrom Space

Light fromthe sun

Reflected heatabsorbed byatmosphere

Reflected heat lost toouter space

Kelter, Carr, Scott, Chemistry A Wolrd of Choices 1999, page 392

Global Warming

HIGH ENERGY, SHORT LIGHT PASSESEASILY THROUGH ATMOSPHERE

ENERGY RELEASEDAS HEAT

LOWER ENERGY, LONGER LIGHT IS BLOCKED BY CO2

AND CH4; ENERGY DOESN’T

ESCAPE INTO SPACE;ATMOSPHERE HEATS UP

CO2 MOLECULES

The Greenhouse Effect

Greenhouse Gases

The Earths Atmosphere

Ozone

Zumdahl, Zumdahl, DeCoste, World of Chemistry 2002, page 309

Carbon Dioxide Levels

Zumdahl, Zumdahl, DeCoste, World of Chemistry 2002, page 310

350

300

250

1000 1500 2000

Year

Atm

osph

eric

C

O2

(ppm

)

(a) Records from Antarctic ice cores (1006-1969 A.D.) (b) Records from monthly air samples, Mauna Loa Observatory, Hawaii (1958-2002)

Copyright © 2007 Pearson Benjamin Cummings. All rights reserved.

Why more CO2 in atmosphere now than 500 years ago?

burning of fossil fuels deforestation

* The burning of ethanol won’t slow greenhouse effect.

C2H5OH + O2 CO2 + H2O

-- coal-- petroleum-- natural gas-- wood

-- urban sprawl-- rain forests-- wildlife areas

• FACT: 15% increase in [CO2] in last 100 years• Cause:

– Change from agricultural to industrial lifestyle– Burning of fossil fuels (petroleum, coal) – Increase CO2 emissions (cars, factories etc…)– Deforestation

• Effects: – Global warming – Melt polar ice caps flooding at sea level– Warming oceans more powerful storms

Greenhouse Effect

350

300

2501000 1500 2000

Year

Atm

osph

eric

C

O2

(ppm

)

Greenhouse Effect

Children and pets left unattended in vehicles with windowsrolled up can die from high temperature in vehicle.

Carbon dioxide in atmosphere traps heat and acts like aglass cover holding in the heat on planet Earth.

insulate home; run dishwasher full; avoid temp. extremes (A/C &

furnace); wash clothes on “warm,” not “hot” mow lawn less often (small

engines)

What can we do?

1. Reduce consumption of fossil fuels.

2. Support environmental organizations.

3. Rely on alternate energy sources.

bike instead of drive; carpool;energy-efficient vehicles

At home:

On the road:

solar, wind energy, hydroelectric power

Sources of Energy