Download chapter19, 2009 APES

Chapter 19
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June 1991: Mount
Pinatubo (Philippines)
exploded
Airborne pollutants,
deaths, and damage
Affected climate
temperature
James Hansen(NASA)
cooled the temp of the
earth by )0.5* over a
19th month period.
Then the earth would
warm
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The overwhelming scientific consensus is that
the earth’s atmosphere is warming rapidly,
mostly because of human activities, and that
this will lead to significant climate change
during this century.
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Over the past 4.7 billion years the climate
has been altered by
◦ Volcanic emissions
◦ Changes in solar input
◦ Movement of the continents
◦ Impacts by meteors
Over the past 900,000 years
◦ Glacial and interglacial periods
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Over the past 10,000 years
◦ Interglacial period, fairly stable climate and
steady average global surface temperature
Over the past 1,000 years
◦ Temperature stable but began to rise during
the last century when forests cleared, fossil
fuel burned
Over the past 100 years
◦ Temperature changes mostly since 1975
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Analysis of radioisotopes in rocks and fossils
Plankton and radioisotopes in ocean
sediments
Tiny bubbles of ancient air found in ice cores
from glaciers
Temperature measurements taken at different
depths from bore holes drilled deep into the
earth’s surface
Pollen from lake/bog bottoms
Tree rings
Historical records - 1861
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Without the natural greenhouse effect, warms the
earth’s lower atmosphere and surface.
Solar energy absorbed by the earth radiates into
the atmosphere as infrared radiation(heat)
1% of earth’s lower atmosphere is compressed of
greenhouse gases- water vapor, carbon dioxide,
methane, and nitrous oxide
◦ Cold, uninhabitable earth
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Since the Industrial Revolution (275 years ago)
◦ CO2, CH4, and N2O emissions higher
◦ Main sources: agriculture, deforestation, and
burning of fossil fuels
Correlation of rising CO2 and CH4 with rising
global temperatures, during past 400,000 years
Countries with the largest CO2 emissions- US,
China, EU-27 contries, Indonesia, Russia, Japan,
India
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Per capita emissions of CO2
Scientific and economic studies
◦ 2007: Field and Marland
560 ppm by 2050 – 1390 by 2100
Tipping point 450 ppm
◦ 2008: Aufhammer and Carson
 China’s CO2 emission growth may be underestimated
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Ice core analysis – 60% of methane emissions
◦ human impact – landfills, raising live stock, extracting
fossil fuels
◦ Nitrous oxide – nitrogen fertilizers
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Intergovernmental Panel on Climate Change
(IPCC)
90–99% likely that lower atmosphere is warming
1906–2005: Ave. temp increased about 0.74˚C
1970–2005: Annual greenhouse emissions up 70%
Past 50 years: Arctic temp rising almost twice as
fast as the rest of the earth
◦ Melting of glaciers and floating sea ice
◦ Prolonged droughts: increasing
◦ Last 100 years: sea levels rose 10–20 cm
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Al Gore and the
IPCC : Nobel
Peace Prize
Natural and
humaninfluenced
factors could
have an effect on
temperature
changes
Drop in average cover of summer arctic ice
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Mathematical models used for predictions
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Global warming: rapid rate
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Human factors are the major cause of
temperature rise since 1950
Human factors will become a greater risk
factor
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Since 1975- satellite and balloon
measurements
◦ Troposphere has warmed
◦ Stratosphere has cooled
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Scientists have concluded that the rapid rise
in global mean temperature could not be the
result of increased solar output
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Solubility of CO2 in ocean water – removes 25-30%
of the carbon dioxide pumped into the lower
atmosphere by human activities. Some of it
converted to insoluble carbonate salts that are
buried in the bottom sediments
Warmer oceans
◦ Solubility decreases increases atmospheric CO2
◦ Coral reefs destroyed
◦ Increased acidity –less carbon dioxide absorbed,
increases growth of some algae
◦ drop in populations of phytoplankton,
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Antarctica’s Southern Ocean and the North Atlantic
Ocean –decrease in carbon dioxide uptake
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Warmer temperatures create more clouds by
increased evaporation of surface water
◦ Thick, light-colored low altitude clouds: decrease
surface temperature
◦ Thin, cirrus clouds at high altitudes: increase
surface temperature
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Effect of jet contrails on climate temperature
– they expand and turn into cirrus clouds that
release heat into the upper troposphere
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Aerosol and soot pollutants
◦ light colored sulfate particles, reflect
sunlight and cool atmosphere
◦ sulfate particles also cool the lower
atmosphere by forming condensation nuclei
that form cooling clouds
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The projected rapid change in the
atmosphere's temperature during this century
is very likely to
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Increase drought and flooding,
shift areas where food can be grown,
raise sea levels,
result in intense heat waves,
cause the premature extinction of many species.
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Very rapid, global change in climate – projected
rapid increase in average temperature in the
lower atmosphere
Worst-case scenarios
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Ecosystems collapsing
Low-lying cities flooded
Wildfires in forests
Prolonged droughts: grasslands become dust bowls
More destructive storms
Glaciers shrinking; rivers drying up
Stepped Art
Fig. 19-7, p. 507
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less moisture in the soil – NPP will decrease
stream flows and available water will decline
Biodiversity will decrease
growth of plants/trees will slow
forest and grassland fires will increase
some lakes/seas will shrink and disappear,
rivers will fail to reach the sea
1-3 billion people will face water shortage
dry climate biomes will increase – savannas,
chapparal,deserts
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global warming be worse in the polar regions
– exposure of darker land, absorb more solar
radiation
floating sea ice disappearing – could affect the
average rate of precipitation in certain areas
Mountain glaciers affected by
◦ Average snowfall, adds to mass in winter
◦ Average warm temperatures- apur their
melting during the summer
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Europe’s Alps
◦ Glaciers are
disappearing
South America
◦ Glaciers are
disappearing
Greenland
◦ Warmer
temperatures
Areas of Glacial Ice Melting
in Greenland
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Largest island: 80% composed of glaciers
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10% of the world’s fresh water
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1996–2007: net loss of ice doubled
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Effect on sea level if melting continues
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Expansion of warm
water and melting of
land based ice–
Water will rise 18-59
cm (0.6-1.9 feet)
during this century
storm surges of 6
meters (20 feet)
accompanying
tropical cyclones and
tsunamis
◦ Degradation and loss of
1/3 of coastal estuaries,
wetlands, and coral reefs
◦ Disruption of coastal
fisheries
◦ Flooding of
 Low-lying barrier islands
and coastal areas
 Agricultural lowlands and
deltas
◦ Contamination of
freshwater aquifers
◦ Submergence of lowlying islands in the Pacific
and Indian Oceans and
the Caribbean
Maldives- Indian Ocean
Melting of permafrost in tundra soils releases
methane and carbon di oxide
Loss of arctic tundra-reduce grazing lands for
caribou
Boreal vegetation would replace tundra
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Melting glaciers, particularly in Greenland
Increased rain in the North Atlantic
Could add enough fresh water to disrupt the
flow of deep and shallow ocean currents
Could climate of Northern Europe. N. America
and Japan
Not thought to be an immediate problem on the
ocean currents
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Heat waves and droughts in some areas- kill
people, reduce crop production, expand deserts
Prolonged rains and flooding(flash floods) from
heavy and prolonged precipitation
Will storms get worse?
◦ More studies needed – Saunders and Lea (2008)
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Hurricanes Katrina and Rita – lost 320 million
big trees
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Most susceptible ecosystems
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Coral reefs
Polar seas
Coastal wetland
High-elevation mountaintops
Alpine and arctic tundra
Changes in water temperature, relative to coral
bleaching threshold
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30% of land –based
plants and animals
will disappear (temp
change 1.5-2.5*C)
What about
◦ Migratory animals
◦ Forests
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Some organisms will
increase
◦ Insects, Fungi,
Microbes
Exploding populations of
mountain pine beetles
Destroy lodge pole pine forests
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Regions of farming may shift
◦ Decrease in tropical and subtropical areas
◦ Increase in northern latitudes
◦ Overall food productivity would decrease because
of less productivity soil
◦ Decrease in food production in farm regions
dependent on rivers fed by snow melt
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Genetically engineered crops more tolerant to
drought
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Deaths from heat waves will increase
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Deaths from cold weather will decrease
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Higher temperatures can cause
◦ Increased flooding
◦ Increase in some forms of air pollution, more O3
◦ More insects, microbes, toxic molds, and fungi
Norman Myers – 150 to 200 million environmental
refugees in this century
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To slow the rate of global warming and
climate change, we can
increase energy efficiency,
sharply reduce greenhouse gas emissions,
rely more on renewable energy resources
slow population growth.
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Governments can
subsidize energy efficiency and renewable
energy use,
tax greenhouse gas emissions,
set up cap-and-trade emission reduction
systems,
help to slow population growth.
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Global problem
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Long-lasting effects
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Long-term political problem
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Harmful and beneficial impacts of climate
change unevenly spread
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Many proposed actions disrupt economies
and lifestyles
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Two approaches
◦ Drastically reduce the amount of greenhouse gas
emissions
◦ Recognize that some warming is unavoidable and
devise strategies to reduce the harmful effects of
global warming
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Will we reach a political tipping point before
we reach irreversible climate change tipping
points?
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Input or prevention strategies
◦ Improve energy efficiency to reduce fossil fuel use
◦ Shift from non-renewable carbon-based fossil fuels
to a mix of carbon-free renewable energy resources
◦ Stop cutting down tropical forests
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Output strategy
◦ Capture and store CO2 -
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Socolow and Pacala
◦ Climate stabilization wedges
◦ Keep CO2 emissions to 2007 levels by 2057
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Brown: need to do more
◦ Cut CO2 emissions by 80% by 2020
◦ 2008 book: Plan B 3.0: Mobilizing to Save
Civilization
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Output solutions
◦ Massive global tree planting – 4 billion need to be
planted
 Wangari Maathai
 Great Wall of Trees: China and Africa
◦ Plant fast-growing perennials such as switch grass
on degraded land which takes carbon dioxide from
the air and stores it in the soil. Can be used to
produce ethanol
SOLUTIONS
Global Warming
Prevention
Cleanup
Cut fossil fuel use
(especially coal)
Remove CO2 from
smokestack and vehicle
emissions
Store (sequester) CO2 by
planting trees
Sequester CO2 deep
underground (with no leaks
allowed)
Sequester CO2 in soil by
using no-till cultivation and
taking cropland out of
production
Sequester CO2 in the deep
ocean (with no leaks
allowed)
Repair leaky natural gas
pipelines and facilities
Use animal feeds that
reduce CH4 emissions from
cows (belching)
Shift from coal to natural gas
Improve energy efficiency
Shift to renewable energy
resources
Transfer energy efficiency
and renewable energy
technologies to
developing countries
Reduce deforestation
Use more sustainable
agriculture and forestry
Limit urban sprawl
Reduce poverty
Slow population growth
Fig. 19-13, p. 515
Stepped Art
Fig. 19-14, p. 515
Some Output Methods for Removing CO2 from the Atmosphere
and storing it
Oil rig
Tanker delivers
CO2 from plant Coal power
to rig
plant
CO2 is pumped
down from rig for
disposal in deep
ocean or under
seafloor sediments
Abandoned
oil field
Tree plantation
Switchgrass
Crop field
CO2 is
pumped
underground
Spent oil or
natural gas
reservoir
Spent coal
bed cavern
Deep, saltwater-filled cavern
= CO2 pumping
= CO2 deposit
Fig. 19-15, p. 516
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Carbon capture and storage (CCS) –
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Several problems with this approach
involves
removing carbon dioxide from the smoke stacks of coalburning power and industrial plants and storing them
somewhere
◦ Power plants using CCS
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 More expensive to build
 None exist
Unproven technology
Large inputs of energy to work
promotes continued use of coal
Effect of government subsidies and tax breaks
Stored CO2 would have to remain sealed forever: no
leaking
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CCS – large scale geo engineering scheme
opposed by scientists because long term effects
on earth’s energy flow, chemical cycling
processes and vital biodiversity are unknown
Injection of sulfate particles into the
stratosphere by balloons, large jet planes, giant
cannons
Huge amounts of sulfur dioxide injected into the
atmosphere every 2 years
◦ Would it have a cooling effect?
◦ Would it accelerate O3 depletion?
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Remove HCl from seawater – reduce ocean
acidity. How would it affect the ecology ?
Pump up nutrient-rich deep ocean water and
cause algal blooms, remove carbon dioxide
and emit dimethyl sulfide which will contribute
to the formation of low clouds that would
reflect sunlight
Re-ice the Arctic – 8,000 ice making barges
Wrap large areas of the glaciers with insulating
blankets
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Short-term costs lower
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Local and global economies may be boosted
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Provide jobs because of new technology
associated with alternative energy
Less expenses for remediation
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Strictly regulate CO2 and CH4 as pollutants
Cap-and-trade approach-political advantage
carbon taxes - levy energy taxes on each unit of
fossil fuel that is burned – tax pollution, not
payrolls
Increase subsidies to encourage use of energyefficient technology
Technology transfer-fund the transfer of green
technologies to phase out older, energy wasting
technologies
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1997: Treaty to slow climate change -2200
delegates from161 nations
1st phase – 174 of the world’s 194 countries (but
not US) ratifying the agreement by mid -2008.
The Kyoto Protocol
◦ Reduce emissions of CO2, CH4, and N2O by 2012 to levels
of 1990
◦ Trading greenhouse gas emissions among countries
◦ Not signed by theUS.(2001) 67% of ppublic upset
 President G.W. Bush’s reasons-would harm US economy
Cap and Trade systems need to have the caps set low to
increase value of the tradable allowances
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2004: Stewart and Wiener
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Should be led by the U.S.
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◦ New treaty needed
Include China, India, Brazil and other developing
countries that are getting industrialized and will
be soon emitting the more than 50% of the
world’s greenhouse gases
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Cap-and-trade emissions program
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Set up achievable 10 year goals – to reduce
greenhouse gases over the next 40 years
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Costa Rica: goal to be carbon neutral by 2030 –
78% from hydroelectric,18% from wind and
geothermal
Norway: aims to be carbon neutral by 2050
China and India must change energy habits
U.S. cities and states (27+ DC: solar and wind)
taking initiatives to reduce carbon emissions
650 cities around the world, including 453 US
cities reduce greenhouse gases
Portland, Oregon – 1993-2005 greenhouse
gases at 1990 levels
Use of energy-efficient appliances and buildings
 Incentives for consumers to use less energy
Has saved California from building 24 new power
plants
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California sued the EPA so that they and 17 other
states can set tougher emission standards
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Major global companies reducing greenhouse
gas emissions- reduce 10-65% below 1990
levels by 2010
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Alcoa
DuPont
IBM
Toyota
GE
Wal-Mart $12 million /year saved by using LED’s
 Fluorescent light bulbs
 Auxiliary power units on truck fleets – no idling
 Carbon Disclosure Project
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Colleges and universities reducing
greenhouse gas emissions
◦ Oberlin College, Ohio, U.S.
◦ 25 Colleges in Pennsylvania, U.S.
◦ Yale University, CT, U.S.
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Largest teach-In Feb 2008-1500 colleges,
climate change and sustainability
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Reduce greenhouse gas emissions as much
as possible (50-85% cut in by 2050) to
prevent the planet from heating up by 2*C
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Move people from low-lying coastal areas
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Limit coastal building
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Remove hazardous material storage tanks
away from the coast
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Genetically engineer crops more tolerant to
drought
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Stockpile 1–5 years of key foods
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Waste less water
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Connect wildlife reserves with corridors
Which do you think is the
most important ?
Develop crops that
need less water
Waste less water
Connect wildlife
reserves with corridors
Move hazardous material
storage tanks away from coast
Move people away
from low-lying
coastal areas
Stockpile 1- to 5-year
supply of key foods
Prohibit new construction
on low-lying coastal areas
or build houses on stilts
Expand existing
wildlife reserves
toward poles
Fig. 19-17, p. 522
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Widespread use of certain chemicals has
reduced ozone levels in the stratosphere,
which allows for more harmful ultraviolet
radiation( UV-A and UV-B) to reach the
earth’s surface.
To reverse ozone depletion, we must stop
producing ozone-depleting chemicals and
adhere to the international treaties that ban
such chemicals.
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Ozone Thinning
◦ Seasonal depletion
in the stratosphere
 Antarctica and
Arctic
 not in tropics
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1930: Midgely
◦ Discovered the first
CFC
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1984: Rowland
and Molina
◦ CFCs (freons)were
depleting O3
Others – halons, hydrobromofluorocarbons (HBFC’s),
methyl bromide, hydrogen chloride, carbon tetrachloride,
methyl chloroform
1988 – less severe ozone
thinning over Arctic from February
to June, loss of 11-38%
When this mass of air breaks up,
large masses of ozone depleted
air flow south to linger over parts
of Europe, N.America,Asia
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Research
◦ CFCs are persistent in the atmosphere
◦ Rise into the stratosphere over 11-20 years
◦ Break down under high-energy UV radiation
 Halogens produced accelerate the
breakdown of O3 to O2
◦ Each CFC molecule can last 65-385 years
1988: Dupont stopped producing CFCs –
stalled for 15 years(1974)
1995: Nobel Prize in chemistry
Sun
UV radiation
Cl
C
F
Ultraviolet light hits a
chlorofluorocarbon (CFC)
molecule, such as CFCl3,
breaking off a chlorine
atom and leaving CFCl2.
Cl
Summary of Reactions
CFCl3 + UV → Cl + CFCl2
Cl + O3 → ClO + O2 Repeated
ClO + O → Cl + O2 many times
Cl
C
Cl
Cl
Cl
F
Cl
Once free, the chlorine
atom is off to attack
another ozone molecule
and begin the cycle again.
O
O
O
O
Ozone
The chlorine atom attacks
an ozone (O3) molecule,
pulling an oxygen atom off
it and leaving an oxygen
molecule (O2).
O
O
O
O
O
O
O
O
O
A free oxygen atom pulls
the oxygen atom off the
Cl
chlorine monoxide
molecule to form O2.
O
Cl
The chlorine atom and the oxygen atom join
to form a chlorine monoxide molecule (ClO).
O
O
Fig. 19-D, p. 525
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Damaging UV-A and UV-B radiation
◦ Increase eye cataracts and skin cancer
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Impair or destroy phytoplankton- Antarctic
base of food web
loss of removal of carbon dioxide from the
atmosphere – worsening global warming
Effects of ozone depletion
Stepped Art
Fig. 19-20, p. 524
This long-wavelength (low-energy) form
of UV radiation causes aging of the skin,
tanning, and sometimes sunburn. It
penetrates deeply and may contribute to
skin cancer.
Ultraviolet Ultraviolet
B
A
This shorter-wavelength (high-energy) form
of UV radiation causes sunburn, premature
aging, and wrinkling. It is largely responsible
for basal and squamous cell carcinomas and
plays a role in malignant melanoma.
Hair
Thin layer of
dead cells
Squamous
cells
Basal layer
Epidermis
Sweat
gland
Melanocyte
cells
Dermis
Basal cell
Blood
vessels
Fig. 19-E (1), p. 526
Fig. 19-E (2), p. 526
This long-wavelength (low-energy) form of UV
radiation causes aging of the skin, tanning,
and sometimes sunburn. It penetrates deeply
and may contribute to skin cancer.
Ultraviolet A
This shorter-wavelength (high-energy) form of UV
radiation causes sunburn, premature aging, and
wrinkling. It is largely responsible for basal and
squamous cell carcinomas and plays a role in
malignant melanoma.
Ultraviolet B
Hair
Thin layer of dead cells
Squamous cells
Epidermis
Basal layer
Sweat gland
Melanocyte cells
Dermis
Blood vessels
Basal cell
Squamous Cell Carcinoma
Basal Cell Carcinoma
Melanoma
Stepped Art
Fig. 19-E, p. 526
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Stop producing all ozone-depleting chemicals
60(1980 levels)–100(1950 levels) years of
recovery of the O3 layer
1987: Montreal Protocol – 36 nations, cut down
35% emissions between1989-2000
1990 – London – 93 countries
1992: Copenhagen Protocol-191 countries
Ozone levels should return to 1980 level by
2068(15 years later than predicted) and 1950
levels by 2108
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Substitutes for CFCs are available
More are being developed
HCFC-22
worst, phase out chemical by 2020 in
developed and 2030 in developing countries,
10 years earlier than agreed in 1992
◦ Substitute chemical
◦ May still be causing ozone depletion