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 Motions Orbit Tilt

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 Volcanoes can cause greenhouse gas 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? The balance between its reflection and absorption of sunlight The balance between its temperature and air pressure How much money it can spend monthly

Why Is The Earth’s Heat Budget Important? It is the reason why we have volcanic eruptions It causes sunspots Changes in it can cause changes in global climate It is a contributor to plate tectonics

What is the average percentage of reflection? Absorption? 20% and 80% 20% and 90% 30% and 70% 60% and 40% 70% and 30%

What Are Examples Of Signs That Climate Is Changing? Observations Temperature Plant Life Tree Rings Glacier Sediments Sea Floor Sediments All Of The Above

What Factors Cause Climate Change? Earth’s Motions Plate Tectonics Sunspots Volcanoes Human Activities All Of The Above

Milutin Milankovitch Said… Humans are the reason for global climate changes The “wobble” of the Earth’s rotation alters seasons and climates The Earth is absorbing less energy from the sun

Large Volcanic Eruptions Can Cause… Short term cooling and long term warming Short term warming and long term cooling No effects to the atmosphere

T/F: The 11 Year Cycle Of Sunspots Changes How Much Energy The Earth Receives True 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? African Countries India China USA Europe Brazil Australia Middle East

CO2 Emissions (Per Person) SOURCE: http://en. wikipedia

Energy Consumption (Per Person)

Carbon Dioxide and Temperature 2005

Carbon Dioxide and Temperature Relationship 2040 2005

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).

If all of the ice caps melted then sea level would raise by 65 m Kennedy Space Center Impact of a 1 m rise in sea level on low-lying areas If all of the ice caps melted then sea level would raise by 65 m Areas subjected to Inundation with a 1 m (~3 ft) rise in sea level Miami Source: Corell, R. W., 2004: Impacts of a warming Arctic. Arctic Climate Impact Assessment (www.acia.uaf.edu) Cambridge University Press (www.cambridge.org).

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 Strongly Agree Agree Disagree Strongly Disagree

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