Climate Control and Ozone Depletion

1
Climate Control and Ozone Depletion

• Chapter 19

2
Core Case Study Studying a Volcano to Understand
Climate Change

• June 1991 Mount Pinatubo (Philippines) exploded
• Airborne pollutants, deaths, and damage
• Affected climate temperature cooled Earth by 1
  degree F over a 19 month period
• Climate predictions based on the forecasts of
  James Hansen of NASA

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Fig. 19-1, p. 496
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19-1 Global Warming and Global Cooling Are Not
New

• 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
• Many fluctuations of several degrees centigrade
• Glacial (100,000 years) and interglacial periods
  (10,000- 25, 000 years )

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Fig. 19-2, p. 498
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Earths Orbital Mechanics

• Milutin Milankovitch (1879-1958), Serbian
  astrophysicist
• First known for his bridge work, Milankovitch was
  
• interned during WWI and during this time first
  began
• to formulate his theories relating Earths
  motions
• and long-term climate change
• A mathematical theory of climate based on the
  seasonal and latitudinal variations of solar
  radiation received by the Earth
• Milankovitch Theory states that as the Earth
  travels around the sun, cyclical variations in
  three elements of Earth-sun geometry combine to
  produce variations in the amount of solar energy
  that reaches Earth

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Earths Orbital Mechanics
(1) Variations in the Earth's orbital
eccentricitythe shape of the orbit around the
sun.
(2) Changes in obliquitychanges in the angle
that Earth's axis makes with the plane of Earth's
orbit
3) Precessionthe change in the direction of the
Earth's axis of rotation, i.e., the axis of
rotation behaves like the spin axis of a top that
is winding down hence it traces a circle on the
celestial sphere over a period of time.
8

• Milutin Milankovitch
• Using these three orbital variations,
  Milankovitch formulated a mathematical model that
  calculated latitudinal differences in insolation
  and the corresponding surface temperature for
  600,000 years prior to the year 1800. He then
  correlated these changes with the growth and
  retreat of the Earths Ice Ages.
• Though his first monograph on the subject was
  published in 1920, it was alternately ignored and
  refuted for about 50 years. As with many areas of
  science, theories predated that observational
  evidence. It wasnt until 1976, when a study
  published in the journal Science examined
  deep-sea sediment cores over 450,000 revealed the
  relationship.

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Global Warming and Global Cooling Are Not New

• Over the past 10,000 years
• Interglacial period
• Over the past 1,000 years
• Temperature stable
• Over the past 100 years
• Temperature changes methods of determination

10
Our Climate, Lives, and Economies Depend on the
Natural Greenhouse Effect

• Without the natural greenhouse effect
• Cold, uninhabitable earth

11
Human Activities Emit Large Quantities of
Greenhouses Gases

• Since the Industrial Revolution
• 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
• Countries with the largest CO2 emissions in 2007
• U.S (25), China (5), European union (27
  countries), Indonesia, Russia, Japan, and India.

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Table 21-1Page 464
Table 21-1 Major Greenhouse Gases from Human
Activities
Greenhouse Gas Carbon dioxide (CO2) Methane
(CH4) Nitrous oxide (N2O) Chlorofluorocarbon
s (CFCs) Hydrochloro- fluorocarbons
(HCFCs) Hydrofluorocarbons (HFCs) Halons Carbo
n tetrachloride
Average Time in the Troposphere 100120
years 1218 years 114120 years 1120
years (65110 years in stratosphere) 9390 15
390 65 42
Human Sources Fossil fuel burning, especially
coal (7075), deforestation, and plant
burning Rice paddies, guts of cattle and
termites, landfills, coal production, coal seams,
and natural gas leaks from oil and gas production
and pipelines Fossil fuel burning, fertilizers,
livestock wastes, and nylon production Air
conditioners, refrigerators, plastic foams Air
conditioners, refrigerators, plastic foams Air
conditioners, refrigerators, plastic foams Fire
extinguishers Cleaning solvent
Relative Warming Potential (compared to
CO2) 1 23 296 9008,300 4702,000 13
012,700 5,500 1,400
Water Vapor None
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The Causes of Global Climate Change
Sulfur Hexafluoride-, SF6 is the most potent
greenhouse gas
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Fig. 19-4, p. 500
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Human Activities Emit Large Quantities of
Greenhouses Gases

• Per capita emissions of CO2
• Scientific and economic studies
• 2007 Field and Marland
• Tipping point
• 2008 Aufhammer and Carson
• Chinas CO2 emission growth may be underestimated
• Ice core analysis of air pollutants

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Fig. 19-3, p. 498
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The Atmosphere Is Warming Mostly Because of Human
Activities (1)

• Intergovernmental Panel on Climate Change (IPCC)
• 9099 likely that lower atmosphere is warming
• 19062005 Ave. temp increased about 0.74C
• 19702005 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 1020 cm

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The Atmosphere Is Warming Mostly Because of Human
Activities

• Al Gore and the IPCC Nobel Peace Prize
• What natural and human-influenced factors could
  have an effect on temperature changes?
• Amplify
• Dampen

21
Five Warmest Years on Record

• 2005
• 1998
• 2002
• 2003
• 2006
• Since 1980, the Earth has experienced
• 19 of its 20 hottest years on record

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What Is the Scientific Consensus about Future
Temperature Change?

• Mathematical models used for predictions
• Global warming rapid rate
• Human factors are the major cause of temperature
  rise since 1950
• Human factors will become a greater risk factor

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Is a Hotter Sun the Culprit?

• Since 1975
• Troposphere has warmed
• Stratosphere has cooled
• This is not what a hotter sun would do

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Can the Oceans Save Us?

• Solubility of CO2 in ocean water
• Warmer oceans
• CO2 levels increasing acidity
• Effect on atmospheric levels of CO2
• Effect on coral reefs
• Antarcticas Southern Ocean and the North
  Atlantic Ocean
• Decrease in CO2 uptake
• Significance on global CO2 levels

25
There Is Uncertainty about the Effects of Cloud
Cover on Global Warming

• Warmer temperatures create more clouds
• Thick, light-colored low altitude clouds
  decrease surface temperature
• Thin, cirrus clouds at high altitudes increase
  surface temperature
• Effect of jet entrails on climate temperature

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Outdoor Air Pollution Can Temporarily Slow Global
Warming

• Aerosol and soot pollutants
• Will not enhance or counteract projected global
  warming
• Fall back to the earth or are washed out of the
  lower atmosphere
• Reduction especially in developed countries

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19-2 Enhanced Global Warming Could Have Severe
Consequences

• Tipping point and irreversible climate change
• Worst-case scenarios
• Ecosystems collapsing
• Low-lying cities flooded
• Wildfires in forests
• Prolonged droughts grasslands become dust bowls
• More destructive storms
• Glaciers shrinking rivers drying up

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Melting of Alaskas Muir Glacier in the popular
Glacier Bay National Park and Preserve between
1948 and 2004.
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Severe Drought Is Increasing The Browning of
the Earth

• Accelerate global warming, lead to more drought,
  hurricanes, prolonged heat waves and
  desertification.
• Biodiversity will decrease
• NPP will decrease
• Dry climate ecosystems will increase

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Ice and Snow Are Melting (1)

• Why will global warming be worse in the polar
  regions?
• Important climate role of floating sea ice
• Mountain glaciers affected by
• Average snowfall
• Average warm temperatures

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Fig. 19-6, p. 501
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Albedo Effect
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Albedo, or reflectivity
Fig. 21-17 p. 480
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Ice and Snow Are Melting

• Europes Alps
• Glaciers are disappearing
• South America
• Glaciers are disappearing
• Greenland
• Warmer temperatures

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Science Focus Melting Ice in Greenland

• Largest island 80 composed of glaciers
• 10 of the worlds fresh water
• 19962007 net loss of ice doubled
• Effect on sea level if melting continues

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Fig. 19-C, p. 508
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Sea Levels Are Rising (1)

• Expansion of warm water
• Melting of land-based ice
• What about Greenland?

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Sea Levels Are Rising (2)

• Projected irreversible effect
• 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 low-lying islands in the Pacific
  and Indian Oceans and the Caribbean

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Thermal expansion

• Thermal expansionWhile thermal expansion is a
  less obvious process than melting ice (mainly
  because you can't see it happening) the IPCC
  projects that thermal expansion will be the
• main component of
• expected sea-level rises
• over the 21st century.

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ALABAMA
GEORGIA
Jacksonville
Tallahassee
Pensacola
Atlantic Ocean
Orlando
Gulf of Mexico
Tampa
FLORIDA
Fort Meyers
Naples
Miami
Key West
Fig. 19-8, p. 509
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Fig. 19-9, p. 510
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Effects of Global Climate Change
Melting Ice and Rising Sea Levels
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Fig. 19-7, p. 507
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Permafrost Is Likely to Melt Another Dangerous
Scenario

• Carbon present as CH4 in permafrost soils and
  lake bottoms
• 2004 Arctic Climate Impact Assessment
• 1020 of the permafrost might melt this century
• Effect on global warming

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Fig. 19-10, p. 510
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Melting permafrost means an increase in soil
bacterial activity and an increase in CH4
emissions.
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Ocean Currents Are Changing but the Threat Is
Unknown

• Melting glaciers, particularly in Greenland
• Increased rain in the North Atlantic
• Not thought to be an immediate problem on the
  ocean currents

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Changing Ocean Currents
Global warming could alter ocean currents and
cause both excessive warming and severe cooling.
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Extreme Weather Will Increase in Some Areas

• Heat waves and droughts in some areas
• Prolonged rains and flooding in other areas
• Will storms get worse?
• More studies needed
• Hurricanes Katrina and Rita

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Global Warming Is a Major Threat to Biodiversity
(1)

• Most susceptible ecosystems
• Coral reefs
• Polar seas
• Coastal wetland
• High-elevation mountaintops
• Alpine and arctic tundra

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Changes in average temperatures of ocean water,
relative to the coral bleaching threshold, past
and projected, 18602100.
Fig. 19-11, p. 512
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Global Warming Is a Major Threat to Biodiversity

• What about
• Migratory animals
• Forests
• Which organisms could increase with global
  warming? Significance?
• Insects
• Fungi
• Microbes

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Changes in Biodiversity
Biomes
Shift of Alpine biomes up mountains and further
North/South
Die-offs

• Coral bleaching die-offs of up to 50 in the
  Indian Ocean

Extinctions

• Golden Toads, Harlequin Frogs, ...

Life Cycles
Gothic marmots emerge from hibernation about a
month earlier than 30 years ago

• The average weight of adult female polar bears
  has decreased by more than 20 over the last 25
  years

Physiology

• Multiple areas affected

Migration
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Fig. 19-12, p. 512
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Effects of Global Climate Change Effects on
Human Health
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Climate Change Will Shift Areas Where Crops Can
Be Grown

• Regions of farming may shift
• Decrease in tropical and subtropical areas
• Increase in northern latitudes
• Less productivity soil not as fertile
• Genetically engineered crops more tolerant to
  drought

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Climate Change Will Threaten the Health of Many
People

• Deaths from heat waves will increase
• Deaths from cold weather will decrease
• Higher temperatures can cause
• Increased flooding
• Increase in some forms of air pollution, more O3
• More insects, microbes, toxic molds, and fungi

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Positive Feedback
66
Positive Feedback

• Oceans currents and CO2 levels
• Cold deep resurface and emit CO2
• Permafrost melting
• CO2 and methane released by decomposition
• Arctic ice melting
• Less reflection of sunlight water and land heat
  up
• Desertification
• Soil dries out and releases CO2

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19-3 Dealing with Climate Change Is Difficult

• Global problem
• Long-lasting effects
• Long-term political problem
• Harmful and beneficial impacts of climate change
  unevenly spread
• Many proposed actions disrupt economies and
  lifestyles

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SOLUTIONS
Global Warming
Cleanup
Prevention
Cut fossil fuel use (especially coal)
Remove CO2 from smokestack and vehicle emissions
Shift from coal to natural gas
Store (sequester) CO2 by planting trees
Improve energy efficiency
Sequester CO2 deep underground (with no leaks
allowed)
Shift to renewable energy resources
Transfer energy efficiency and renewable energy
technologies to developing countries
Sequester CO2 in soil by using no-till
cultivation and taking cropland out of production
Reduce deforestation
Sequester CO2 in the deep ocean (with no leaks
allowed)
Use more sustainable agriculture and forestry
Repair leaky natural gas pipelines and facilities
Limit urban sprawl
Use animal feeds that reduce CH4 emissions from
cows (belching)
Reduce poverty
Slow population growth
Fig. 19-13, p. 515
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What Are Our Options?

• Two approaches
• Drastically reduce the amount of greenhouse gas
  emissions
• Devise strategies to reduce the harmful effects
  of global warming
• Will we reach a political tipping point before we
  reach irreversible climate change tipping points?

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Avoiding Catastrophe We Can Reduce the Threat of
Climate Change

• Input or prevention strategies
• Improve energy efficiency to reduce fossil fuel
  use
• Stop cutting down tropical forests
• Output strategy
• Capture and store CO2

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Avoiding Catastrophe We Can Reduce the Threat of
Climate Change

• Socolow and Pacala
• Climate stabilization wedges
• Keep CO2 emissions to 2007 levels by 2057
• 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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Fig. 19-14, p. 515
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Avoiding Catastrophe We Can Reduce the Threat of
Climate Change (3)

• Output solutions
• Massive global tree planting how many?
• Wangari Maathai
• Great Wall of Trees China and Africa
• Plant fast-growing perennials on degraded land
• Capturing and storing CO2

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Case Study Is Capturing and Storing CO2 the
Answer? (1)

• Carbon capture and storage (CCS) next slide
• Several problems with this approach
• Power plants using CCS
• More expensive to build
• None exist
• Unproven technology
• Large inputs of energy to work
• Increasing CO2 emissions

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Output methods for removing carbon dioxide from
the atmosphere
Fig. 19-15, p. 516
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Case Study Is Capturing and Storing CO2 the
Answer?

• Problems with carbon capture and storage cont
• Promotes the continued use of coal (worlds
  dirtiest fuel)
• Effect of government subsidies and tax breaks
• Stored CO2 would have to remain sealed forever
  no leaking

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Should We Use Geo-Engineering Schemes to Help
Slow Climate Change?

• CCS- Carbon Capture and Stsorage
• Injection of sulfate particles into the
  stratosphere
• Would it have a cooling effect?
• Would it accelerate O3 depletion?

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Should We Use Geo-Engineering Schemes to Help
Slow Climate Change?

• Remove HCl from seawater
• Effects on ecology?
• Pump up nutrient-rich deep ocean water and cause
  algal blooms
• Re-ice the Arctic
• If any of these fixes fail, what about a rebound
  effect?

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Governments Can Help Reduce the Threat of Climate
Change

• Strictly regulate CO2 and CH4 as pollutants
• Cap-and-trade approach
• Increase subsidies to encourage use of
  energy-efficient technology
• Technology transfer

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Governments Can Enter into International Climate
Negotiations The Kyoto Protocol

• 1997 Treaty to slow climate change
• The Kyoto Protocol
• Treaty on global warming which first phase went
  into effect January, 2005 with 189 countries
  participating.
• It requires 38 participating developed countries
  to reduce emissions of CO2, CH4, and N2O by 2012
  to levels of 1990
• Trading greenhouse gas emissions among countries
• Not signed by the U.S.
• U.S. did not sign because developing countries
  such as China, India and Brazil were excluded.

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Some Governments Are Leading the Way

• Costa Rica goal to be carbon neutral by 2030
• Norway aims to be carbon neutral by 2050
• China and India must change energy habits
• U.S. cities and states taking initiatives to
  reduce carbon emissions

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Some Companies and Schools Are Reducing Their
Carbon Footprints

• Major global companies reducing greenhouse gas
  emissions
• Alcoa
• DuPont
• IBM
• Toyota
• GE
• Wal-Mart
• Fluorescent light bulbs
• Auxiliary power units on truck fleets

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Fig. 19-16, p. 522
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19-4 Our Use of Certain Chemicals
Threatens the Ozone Layer

• Ozone Thinning
• Seasonal depletion in the stratosphere
• Antarctica and Arctic
• Antarctic Spring(October)
• 1930 Midgely
• Discovered the first CFC
• 1984 Rowland and Molina
• CFCs were depleting O3
• Other ozone-depleting chemicals

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Ozone Depletion in the Stratosphere

• The Causes of Ozone Depletion
• Main problem CFCs (chlorofluorocarbons)
• Other chemicals
• Halons
• Methyl bromide
• Methyl chloroform (trichloroethylene)
• Carbon tetrachloride
• Nitrous oxide

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Science Focus Rowland and MolineA Scientific
Story of Courage and Persistence

• 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
• 1995 Nobel Prize in chemistry

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Chlorofluorocarbons or CFCs

• First produced by General Motors Corporation in
  1928, CFCs were created as a replacement to the
  toxic refrigerant ammonia
• CFCs have also been used as a propellant in spray
  cans, cleaner for electronics, sterilant for
  hospital equipment, and to produce the bubbles in
  Styrofoam

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Global average total ozone values in the
stratosphere at a certain latitude, 19792005
Fig. 19-18, p. 523
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Massive ozone thinning over Antarctica in 2007
Fig. 19-19, p. 524
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Sun
Ultraviolet light hits a chlorofluorocarbon (CFC)
molecule, such as CFCl3, breaking off a chlorine
atom and leaving CFCl2.
Summary of Reactions CFCl3 UV ? Cl CFCl2
Cl O3 ? ClO O2
Repeated many times
UV radiation
ClO O ? Cl O2
Cl
Cl
Cl
C
C
F
Cl
Cl
Cl
F
Once free, the chlorine atom is off to attack
another ozone molecule and begin the cycle again.
Cl
O
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
A free oxygen atom pulls the oxygen atom off the
chlorine monoxide molecule to form O2.

O
O
O
O
Cl
O
O
O
O
Cl
O
The chlorine atom and the oxygen atom join to
form a chlorine monoxide molecule (ClO).
O
Fig. 19-D, p. 525
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• A single chlorine atom removes about 100,000
  ozone molecules before it is taken out of
  operation by other substances

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Terpenes

• Terpenes are a class of hydrocarbons produced
  primarily by conifers.
• A viable substitute for CFCs

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Why Should We Worry about Ozone Depletion?

• Damaging UV-A and UV-B radiation
• Increase eye cataracts and skin cancer
• Impair or destroy phytoplankton
• Significance?

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Stepped Art
Fig. 19-20, p. 524
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Science Focus Skin Cancer

• Squamous cell carcinoma
• Basal cell carcinoma
• Melanoma
• Effect of UV-B radiation
• How safe are tanning salons?

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Stepped Art
Fig. 19-E, p. 526
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Cataracts
www.snec.com.sg/clinical_services/ cataract.asp
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Fig. 19-F, p. 527
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We Can Reverse Stratospheric Ozone Depletion

• Stop producing all ozone-depleting chemicals
• 60100 years of recovery of the O3 layer
• 1987 Montreal Protocol
• (1987) stipulated a phase out of CFCs, halons,
  CCl4, CH3CCl3 by 2000 in participating
  countries.
• 1990 London Protocol
• a total phase out of CFCs absolutely necessary
  by 2000.
• 1992 Copenhagen Protocol
• (1992) MDCs agree to stop production by 1996
  (U.S. included this in the 1990 CAA) and to
  financially assist the phase out in LDCs by
  2010.

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We Can Reverse Stratospheric Ozone Depletion

• Substitutes for CFCs are available
• More are being developed
• HCFC-22
• Substitute chemical
• May still be causing ozone depletion