Unit 11 Notes: Climate Change Chapter 21. Earth’s Heat Budget Changes in Earth’s heat budget can change climate The heat budget is a balance between reflection.

Unit 11 Notes: Climate Change

Chapter 21

Earth’s Heat Budget •Changes in Earth’s heat budget can change climate•The heat budget is a balance between reflection and absorption.

IMPORTANT: Because 30% of the electromagnetic energy from the Sun has been reflected away, only 70% remains to interact with the Earth, and warm it up. 20% of the energy from the Sun is absorbed by the atmosphere as a whole heating it up. This leaves 50% of the Sun’s energy to heat both the surface of the Earth, as well as the oceans, lakes and streams.

Earth’s Heat Budget

• Reflection– Atmosphere

reflects 5% – Clouds surface

reflect 20%– Earth’s surface

reflects 5% = 30% Total

• If the reflection is increased, the temperature will decrease

Earth’s Heat Budget• Absorption

– Atmosphere absorbs 20% – Earth’s surface absorbs 50% = 70% Total

• If the absorption is increased the temperature will increase.

• Right now the temperature is increasing, one reason is due to an increase in atmospheric absorption (Greenhouse Gases)

How do we know climate is changing?

• Evidence• Direct (to understand

present climates)– Observations

– Temperature

– Plant life

• Indirect (to predict past climates)

– Sea Floor Sediments

– Glacier Samples (oxygen, distribution of shells)

– Tree Rings

Carbon Dioxide and Temperature

What factors cause climate change?

• Earth’s Motions

• Plate Tectonics

• Sunspots

• Volcanoes

• Human Impacts

Earth’s MotionsTilt Orbit

Earth’s Motions

• Milutin Milankovitch– The Shape of Earth’s Orbit Changes– The Tilt and Axis of Rotation “Wobbles”

• These can affect seasons over long periods of time, changing the climate– This is possibly the reason for changes in ice

cover during the last Ice Age

Plate Tectonics Greenland has Tropical Plant Fossils

~200 million years

Plate Tectonics

• Can change a specific area’s climate (Greenland)

• Can change global climate– Wind patterns– Ocean Currents– Ice sheets

• Continents closer to poles = more ice = more reflection of sunlight = decrease in temp

• Continents farther from poles = less ice sheets = more absorption of sunlight = increase in temp

Distributes heat differently

Volcanoes

• Mt Pinatubo (1991)• Sent 20-30mega tons

of sulfurous aerosols into the air– Ash, dust, gases

containing sulfur compounds

• reflect sunlight into space

• What would happen to temperatures?

Volcanoes

• After the Mt Pinatubo eruption the global temperature fell ~0.5°C or 0.9°F the next year– The ash and sulfuric compounds actually

reflected sunlight back into space

BUT . . .

What else do volcanoes release?

Carbon Dioxide

And What is Carbon Dioxide?

Volcanoes

• Carbon Dioxide is a – Greenhouse gases cause temperatures to

increase

• Volcanoes can cause– Short term cooling (aerosols and sulfuric

compounds)– Long term warming (carbon dioxide)

greenhouse gas

Sunspots

• There is an 11 year sunspot cycle that changes how much radiation is given off by the sun.– More sunspots = More

energy

What Is Earth’s Heat Budget?

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1. The balance between its reflection and absorption of sunlight

2. The balance between its temperature and air pressure

3. How much money it can spend monthly

Why Is The Earth’s Heat Budget Important?

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1. It is the reason why we have volcanic eruptions

2. It causes sunspots

3. Changes in it can cause changes in global climate

4. It is a contributor to plate tectonics

What is the average percentage of reflection? Absorption?

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1. 20% and 80%

2. 20% and 90%

3. 30% and 70%

4. 60% and 40%

5. 70% and 30%

What Are Examples Of Signs That Climate Is Changing?

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1. Observations

2. Temperature

3. Plant Life

4. Tree Rings

5. Glacier Sediments

6. Sea Floor Sediments

7. All Of The Above

What Factors Cause Climate Change?

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1. Earth’s Motions

2. Plate Tectonics

3. Sunspots

4. Volcanoes

5. Human Activities

6. All Of The Above

Milutin Milankovitch Said…

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1. Humans are the reason for global climate changes

2. The “wobble” of the Earth’s rotation alters seasons and climates

3. The Earth is absorbing less energy from the sun

Large Volcanic Eruptions Can Cause…

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1. Short term cooling and long term warming

2. Short term warming and long term cooling

3. No effects to the atmosphere

T/F: The 11 Year Cycle Of Sunspots Changes How Much Energy The Earth Receives

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0%0%

1. True

2. False

Unit 11 Notes: Fossil Fuels

It is evident that climate has been changing without humans but do we have an impact

on climate change?

Fossil Fuels

• Fossil fuel use is one way humans impact the planet.

• Climate is affected because CO2 and other gases are emitted into the atmosphere.

Fossil Fuels

• Fossil fuels – The sun’s energy trapped

within Earth’s crust– The hydrocarbons were

stored mainly in plants (photosynthesis)

• Can be coal, natural gas, and oil (petroleum).

• Used for MANY things… not just power.

Fossil Fuels

Consequences of Fossil Fuel Use

Caused by Impacts

Temperature Increase

Increased greenhouse gases in atmosphere

Break down of ocean currents, changes in climate patterns, loss of agricultural space

Pollution Increased emission use will increase pollutants

Air quality, health risks, species loss

Sea Level Rise Water expansion, melting of land ice (glaciers)

Loss of coastal space, species loss, changes in migration

Who Are The Worst Offenders Of CO2 Emissions and Energy Use?

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1. African Countries

2. India

3. China

4. USA

5. Europe

6. Brazil

7. Australia

8. Middle East

CO2 Emissions (Per Person)SOURCE:

http://en.wikipedia.org/wiki/List_of_countries_by_carbon_dioxide_emissions_per_capita

Energy Consumption (Per Person)

Carbon Dioxide and Temperature

2005

Carbon Dioxide and Temperature Relationship

2005

2040

Carbon Dioxide and Temperature Relationship

“Worst Case Scenario”(fossil intensive)

2100

Future Temperature Predictions

NASA photographs show the minimum Arctic sea ice concentration in 1979 at left and in 2003.Satellite passive microwave data since 1970s indicate a 3% decrease per decade in arctic sea ice extent.

Source:

Corell, R. W., 2004: Impacts of a warming Arctic. Arctic Climate Impact Assessment (www.acia.uaf.edu) Cambridge University Press (www.cambridge.org).

Areas subjected to Inundation with a 1 m(~3 ft) rise in sea level

Kennedy SpaceCenter

Miami

Impact of a 1 mrise in sea levelon low-lying areas

Source:

Corell, R. W., 2004: Impacts of a warming Arctic. Arctic Climate Impact Assessment (www.acia.uaf.edu) Cambridge University Press (www.cambridge.org).

If all of the ice caps melted then sea level would raise by 65 m

To sum it up. . .

• Climate has changed a lot over Earth’s history

• There are many factors to climate change– Some we have no control over and some we

do have control over

• Will Earth survive if the climate changes A LOT?– Yes, but will we?

Humans Are The Only Reason For Global Warming

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1. Strongly Agree

2. Agree

3. Disagree

4. Strongly Disagree

T/F: Our Reliance On Fossil Fuels Will Continue Into The Foreseeable Future…

1 2

0%0%

1. True

2. False