Willenbrock - Physics of Climate Change 1

Physics of Climate Change

Scott Willenbrock

Department of Physics

University of Illinois at Urbana-Champaign

Saturday Physics for Everyone

October 1, 2011

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Some good reading• Physics for Future Presidents (R. Muller)

• Beyond Smoke and Mirrors (B. Richter)

• Sustainable Energy (D. MacKay) - online

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Phys 150 Physics of Societal Issues

• Next offered Spring 2012

• Satisfies Physics Sciences requirement and

Quantitative Reasoning II requirement

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QuestionHow does your body get rid of heat?

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QuestionHow does your body get rid of heat?

• Conduction

• Convection

• Evaporation

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QuestionHow does the Earth get rid of heat?

• Conduction?

• Convection?

• Evaporation?

Heated ball

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QuestionHow does the Earth get rid of heat?

• Conduction? No

• Convection? No

• Evaporation? No

• Radiation!

Your body also uses radiation to get rid of heat!

Light bulb

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Infrared RadiationThe Earth (and your body) emit Infrared Radiation.

Prism

Infrared

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Infrared RadiationThe Earth (and your body) emit Infrared Radiation.

Prism

Infrared

Infrared Thermography

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Sun and EarthThe Sun and Earth are just like the torch and metal ball. Infrared radiation

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Sun and EarthThe Sun and Earth are just like the torch and metal ball. Infrared radiation

T = 26 0F ???

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Earth’s atmosphereThe atmosphere acts like a blanket.

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Earth’s atmosphereThe atmosphere acts like a blanket.

T = 57 0F

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Earth’s atmosphereThe atmosphere acts like a leaky blanket.

T = 57 0F

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Carbon Dioxide (CO2)Earth’s atmosphere is

• 80% Nitrogen

• 20% Oxygen

• <1% Water vapor

• 0.039% Carbon Dioxide

That tiny amount of CO2 is extremely important!

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Carbon Dioxide (CO2)Earth’s atmosphere is

• 80% Nitrogen

• 20% Oxygen

• <1% Water vapor

• 0.039% Carbon Dioxide

That tiny amount of CO2 is extremely important!But adding more is very risky! It makes the

blanket less leaky.

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Carbon Dioxide (CO2)

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QuestionWhich of these are evidence for human-caused global warming?

A. Rising surface temperature

B. Rising sea level

C. Melting snow and ice

D. All of the above

E. None of the above

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QuestionWhich of these are evidence for human-caused global warming?

A. Rising surface temperature

B. Rising sea level

C. Melting snow and ice

D. All of the above

E. None of the above

They are all true, but that does not imply that they are caused by humans

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IPCC 2007

Water expansion

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Muir Glacier, August 1941

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Muir Glacier, August 2004

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North Pole

Floating ice

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Temperature: 12,000 years

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Temperature: 400,000 years

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• Good feedback:

More CO2 -> More water vapor -> More clouds

Temperature: 400,000 years

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• Good feedback:

More CO2 -> More water vapor -> More clouds

• Bad feedback:

More CO2 -> More melting -> More methane

Temperature: 400,000 years

Methane is much worse than CO2

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• Without atmosphere: 90 0F

Venus

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• Without atmosphere: 90 0F

• With atmosphere: 800 0F

Venus

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Computer models

Predicting the futureIPCC 2007

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What can we do?

A lot!

• Energy efficiency

• End deforestation

• Wind and Solar power

• Carbon Dioxide capture and storage

• Biofuels

• Nuclear power

• Geoengineering

• …

Light bulbs

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Conclusion

There is no conclusion

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