Transcript Climate Change - Cloudfront.net

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?
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•
•
•
Earth’s Motions
Plate Tectonics
Sunspots
Volcanoes
Human Impacts
Earth’s Motions
Tilt
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
~200 million years
Greenland
has Tropical
Plant Fossils
Plate Tectonics
• Can change a specific area’s climate
(Greenland)
• Can change global climate
– Wind patterns
– Ocean Currents
– Ice sheets
Distributes heat differently
• 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
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 gas
– Greenhouse gases cause temperatures to
increase
• Volcanoes can cause
– Short term cooling (aerosols and sulfuric
compounds)
– Long term warming (carbon dioxide)
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?
1.
2.
3.
The balance between its
reflection and
absorption of sunlight
The balance between its
temperature and air
pressure
How much money it can
spend monthly
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0%
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Why Is The Earth’s Heat Budget
Important?
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
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What is the average percentage of
reflection? Absorption?
1.
2.
3.
4.
5.
20% and 80%
20% and 90%
30% and 70%
60% and 40%
70% and 30%
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What Are Examples Of Signs That
Climate Is Changing?
1.
2.
3.
4.
5.
6.
Observations
Temperature
Plant Life
Tree Rings
Glacier Sediments
Sea Floor
Sediments
7. All Of The Above
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What Factors Cause Climate
Change?
1.
2.
3.
4.
5.
6.
Earth’s Motions
Plate Tectonics
Sunspots
Volcanoes
Human Activities
All Of The Above
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Milutin Milankovitch Said…
1.
2.
3.
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
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Large Volcanic Eruptions Can
Cause…
1. Short term cooling
and long term
warming
2. Short term
warming and long
term cooling
3. No effects to the
atmosphere
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T/F: The 11 Year Cycle Of Sunspots Changes
How Much Energy The Earth Receives
1. True
2. False
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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 Caused by
Fossil Fuel Use
Temperature
Increase
Impacts
Break down of
Increased
greenhouse gases ocean currents,
changes in climate
in atmosphere
patterns, loss of
agricultural space
Pollution
Sea Level Rise
Increased
emission use will
increase
pollutants
Water expansion,
melting of land ice
(glaciers)
Air quality, health
risks, species loss
Loss of coastal
space, species
loss, changes in
migration
Who Are The Worst Offenders Of
CO2 Emissions and Energy Use?
1.
2.
3.
4.
5.
6.
7.
8.
African Countries
India
China
USA
Europe
Brazil
Australia
Middle East
0%
0%
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2
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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
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).
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
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2.
3.
4.
Strongly Agree
Agree
Disagree
Strongly Disagree
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T/F: Our Reliance On Fossil Fuels Will
Continue Into The Foreseeable Future…
1. True
2. False
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