Transcript Document 7134886

ATMOSPHERE AND
CLIMATE
Greenhouse gases, global
warming and the ozone layer
The Atmosphere
• Is a thin layer of gases that surrounds the earth
• Extends thousands of km above the surface
• The reason there is life on Earth – we are
protected from most of the sun’s radiation
• Allows some light to reach the surface, supplying
energy and allowing photosynthesis (O2 and CO2)
• 78% nitrogen, 21% oxygen, 1%= water vapor,
argon, carbon dioxide, neon, helium, and other
gases
HOW PHOTOSYNTHESIS CHANGED THE
ATMOSPHERE
• The early atmosphere contained little
oxygen.
• Bacteria appeared about 4 bya and evolved
the ability to perform photosynthesis
6CO2 + 6H2O + sun energy → C6H12O6 + 6O2
The 4 Layers
Troposphere
– 75–80% of the earth’s air mass
– Closest to the earth's surface
– 0-11 km above sea level
– Chemical composition of air
• Nitrogen 78%
• Oxygen 21%
• H20, CO2, trace amounts of others (Ar)
– Weather, climate and all life forms exist here
– As altitude increases, temperature decreases
Stratosphere
• 11-50 km (6-30 miles) above Earth's surface
– Similar composition to the troposphere, with 2
exceptions
• Much less water (1/1000)
• O3, ozone layer
• As altitude increases, temperature increases
• Air motion is horizontal
• Airplanes fly here
Mesosphere
 50-80 km (30-50 miles)
 Middle atmosphere – Air thin, pressure low,
 Need oxygen to live in this region. Air quite cold
-90°C (-130°F) near the top of mesosphere
Thermosphere
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80-500 km (50-310 miles)
Very few atoms and molecules in this region.
Intense UV – breaks O2 and N2 bonds
International Space Station is here
Greenhouse Effect
• Greenhouse effect – the trapping of infrared
radiation from the sun by gases in earth’s
atmosphere which warms the planet
• Raises earth’s temp to an average of 59 ⁰F.
Without the
greenhouse effect,
the average temp
would be 0⁰F.
GREENHOUSE GASES
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CARBON DIOXIDE
METHANE
NITROUS OXIDE
CFCs
WATER VAPOR
Bill Nye
Greenhouse Gases
CO2 – most abundant greenhouse gas (GHG)
Sources: burning fossil fuels, deforestation
Ice cores have shown that CO2 increasing in
atmosphere – 35% higher than pre-Industrial Rev.
• Ocean acts as “sink,” absorbing large amounts.
• Vegetation acts as a sink (until it dies or is cut
down)
• 1 kg burned fossil fuels = 3 kg CO2
Vostok Ice Core
• Deepest drilling of ice took
place.
• The ice removed was nearly
a half a million years old.
• Graph = CO2 levels going
back to over 400,000 years
before present.
• The (kyr BP) means
kilo=1,000 years Before
Present.
• CO2 rises and falls about
every 100,000 years.
• At present we are at a high
point again.
Global Warming/climate change
• Global warming – increase in Earth’s average
surface temp. caused by an increase in greenhouse
gases
• “runaway greenhouse effect”
• Earth’s average temperature has risen 1 ° F in last
100 years.
• Some argue natural fluctuation; however,
corresponds w/ rising greenhouse gases
CO2 - DiD you know…
• Burning 1 gallon of gasoline produces 9 kg of carbon
dioxide?
• Using one kWh of electricity from a coal-fired
generating plant produces 1 kg of carbon dioxide?
• Burning 100 cubic feet of natural gas produces 5.5
kg of carbon dioxide?
• 1 kg= 2.2 pounds So 1 gallon produces almost 20
pounds of CO2
The Jones Family
• Complete the worksheet to see how the Jones
family contributes to greenhouse gas
emissions.
CO2 Emissions
• Countries:
– Largest emitters: China (6534 million metric tons):
US (5833): Russia (1729):
India (1495):
Japan (1214)
• Per Capita:
– Australia - 20.8 tons (437, country)
– US- 19.8 tons
– China – 4.91
– India: 1.31
Other Greenhouse Gases
Methane (CH4) – 21 times more warming effect than
CO2 and increasing at 8 times the rate.
• Methane production is faster than broken down
• Main sources are wetlands, rice fields, fossil fuels,
livestock, and landfills
• Remains in the air about 12 years
Greenhouse Gases
• Nitrous oxides – slow to breakdown (120 yrs)
– Sources are fossil fuels, fertilizers, deforestation
• CFCs– slow breakdown; absorb 10,000 X more
infrared than CO2 (100 + years)
– Sources are foams, aerosols, refrigerants, solvents, air
conditioners
• Water vapor – Warmed by CO2,
the atmosphere is thus able to
absorb more water vapor. And
that water vapor, in turn, causes
further warming—it amplifies
the effects of carbon dioxide.
• Global average temperatures - surface temperatures collected
from land and ocean-based stations .
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Compiled by the Climatic Research Unit of the University of East Anglia and the Hadley Centre of
the UK Meteorological Office.
Predicted Results Of Global
Warming
• Weather patterns will change - more
hurricanes, typhoons, flooding and droughts
• Agriculture – weather patterns will move
farther north, shifting farmland
• Sea Levels - polar regions warm, icebergs
melt, sea levels rise. Warming water also
expands. Coastal areas may flood
• http://news.discovery.com/videos/global-warming-videos/
(Walrus, tiger, Alaska)
Melting of Alaska’s Muir Glacier
between 1948 and 2004
Predicted Results Of Global
Warming
• Human health will be affected
– more infectious diseases.
– Diseases that normally occur near equator will
move northward. Diseases spread by mosquitoes
and other insects due to warmer/wetter climates.
Predicted Results Of Global
Warming
• Plant and animal species may migrate to maintain their
preferred habitats
• Not all plants can adapt- cannot disperse their seeds
adequately
• Certain birds/fishes may migrate
• Not all can adapt- ponds will dry up,
land-locked fish cannot seek colder
rivers
• Those that cannot adapt/migrate
may experience regional extinction
Blue winged teal
WHAT DO YOU REMEMBER????
• 1. List 4 greenhouse gases.
• 2. Without the greenhouse effect, Earth’s
temperature would be ____F instead of ____F.
• 3. Write the layers of the atmosphere starting
with the one closest to Earth.
• 4. In which layer is the ozone layer?
• 5. In which layer does weather occur?
6. What is the most common greenhouse gas?
7. Which ghg comes from landfills, cows and
wetlands?
8. List 2 “sinks” for carbon dioxide- this means
what 2 things store large amounts of CO2
9. Which country emits the most CO2?
10. List 4 possible results of global warming.
• Teachers domain- global warming
Albedo & Global Warming
(albedo= ability of a surface to reflect
light)
• Rising global temperatures cause greater evaporation
of water vapor into the atmosphere
• Water vapor is a powerful greenhouse gas, so an
increase in water vapor might produce more
warming.
OR
• More water vapor might cause more clouds to form,
increasing Earth's overall albedo, & reflecting
incoming sunlight back into space.
• This would provide a net cooling effect.
• Might possibly induce a period of "global cooling"
Projected Effects of Global Warming and the Resulting Changes in
Global Climate
Global Cooling
• Global cooling: natural
• Planetary albedo – low, thick clouds reflect
sunlight, prevent warming
• Volcanoes – dust reflect radiation
• Sulfate aerosols – from pollutants, create
haze, reflecting sunlight
Cap and Trade System
• The goal: To steadily reduce carbon dioxide and
other greenhouse gas emissions economy-wide in a
cost-effective manner.
• The cap: Each large-scale emitter, or company, will
have a limit on the amount of greenhouse gas that
it can emit.
• The trade: It will be cheaper or easier for some
companies to reduce their emissions below their
required limit than others. These more efficient
companies, who emit less than their allowance, can
sell their extra permits to companies that are not
able to make reductions as easily.
• Output solutions
– Massive global
tree planting;
how many?
• Wangari Maathai
• Great Wall of
Trees: China and
Africa
– Plant fastgrowing
perennials on
degraded land
– Capturing and
storing CO2
Fifteen Ways to Cut CO2 Emissions
We Can Prepare for the Harmful
Effects of Climate Change
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Reduce greenhouse gas emissions as much as possible
Move people from low-lying coastal areas
Limit coastal building
Remove hazardous material storage tanks away from
the coast
Genetically engineer crops more tolerant to drought
Stockpile 1–5 years of key foods
Waste less water
Connect wildlife reserves with corridors
REVIEW
• 1. Name the 5 greenhouse gases.
• 2. What is the main greenhouse gas?
• 3. Why is the greenhouse effect good for our
planet? Why is it harmful?
• 4. Name 3 sources of CO2 and CH4.
• 5. Name 2 sinks for CO2.
• 6. List 5 effects of global warming.
• 7. List 5 things you can do to reduce global
warming.
• 8. How can we prepare for global warming?
• 9. Name 3 sources of global cooling.
• VIDEO: NOVA: WHAT’S UP
WITH THE WEATHER
THE OZONE LAYER
• O3
• Located in the stratosphere
• Absorbs most of the UV light from the sun
– UV light can cause genetic damage to living
organisms- can cause skin cancer, faster aging, and
cataracts, can kill one-celled organisms
(phytoplankton) that live in the surface of the
ocean, and interfere with photosynthesis, resulting
in lower crop yields
• The ozone in the stratosphere acts as a
sunscreen for Earth and its inhabitants.
OZONE EATERS
• CFCs (Chlorofluorocarbons) – used in
refrigerants, air conditioners, styrofoam and
propellants because they are chemically
stable- they do not break down into other
substances or combine with other
substances.
• They are unreactive, odorless,
nonflammable, nontoxic, noncorrosive and
inexpensive to make.
• BUT, they do break apart in the stratosphere.
CFCs
• CFCs that are
released in the
troposphere can
take 10-20 years to
float into the
stratosphere.
• One single chlorine
atom can destroy
10,000 + ozone
molecules and
remain in the
stratosphere 65-385
years!
STOPPING THE OZONE EATERS
75-85% of the ozone loss was from CFCs
and other ozone depleting chemicals
• CFC containing products have been banned,
and the ozone hole is getting smaller.
• CFCs remain active for more than 30 years, so
it will take decades for the layer to recover.
THE NUMBER 1 SOURCE OF CFCs IS LEAKING
AIR CONDITIONERS!
CFCs
• A greenhouse gas AND an ozone-depleting
chemical.
• video clip
• www.teachersdomain.org/asset/ttv10_vid_oz
one/s from Teacher’s Domain
• http://http://www.teachersdomain.org/asset/
phy03_vid_greenhouse2/
• http://www.teachersdomain.org/asset/ttv10_
vid_aerosols/
REVIEW
1. In what layer of the earth’s atmosphere is
the ozone layer?
2. Why is the ozone layer beneficial?
3. What is the main chemical that affects the
ozone layer?
4. Why was this chemical used in so many
products?
6. What is the main source of CFC emissions?
• You fill your tank with 13 gallons of gas. How
much CO2 will be produced by burning this
amount of CO2?
• 13 gallons X 20 poundsCO2 = 260 pounds
1 gallon
How much CO2 is produced if you use 150 kWh
of electricity in a month?
150 kWh x 2 pounds = 300 pounds CO2
1 kWh
• The average amount of CO2 per capita
produced in America is 19.8 tons, which is
39, 600 pounds!