Climate Change and Ozone Loss

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Climate Change and Ozone Loss
G. Tyler Millers Living in the Environment 13th
Edition Chapter 18
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Key Concepts

• How does the Earths climate fluctuate?
• What factors affect climate?
• What are the possible affects of global warming?
• How are human activities affecting the ozone
  layer?

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Past Global Temperatures
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Past Global Temperatures
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Recent Trends in Global Temperature
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Recent Trends in Global Temperature
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Climate Change

• Past globaltemperatures

• Recent trends in global temperatures

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How do we know what past temperature changes were?

• Radioisotopes in rocks and fossils
• Plankton and radioisotopes in ocean sediments
• Pollen from lake bottoms
• Ice cores from ancient glaciers
• Tree rings
• Radioisotopes in corals
• Historical records
• Temperature measurements

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The Natural Greenhouse Effect(tropospheric
heating effect)
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Natural Cooling Process
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Greenhouse Gases in the Largest Concentration

• Water Vapor
• Carbon Dioxide

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Hydrologic (Water) Cycle
?
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The Carbon Cycle (Terrestrial)
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The Carbon Cycle (Aquatic)
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Greenhouse Gases from Human Activities
Greenhouse Gas Average Time in the Troposphere Relative Warming Potential (CO2)
Carbon Dioxide 50-120 years 1
Methane 12-18 years 23
Nitrous Oxide 114-120 years 296
Chloroflorocarbons 11-20 years 900-8,300
Hydrochloro-flurocarbons 9-390 years 470-2,000
Hydroflurocarbons 15-390 years 130-12,700
Halons 65 years 5,500
Carbon Tetrachloride 42 years 1,400
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Climate Change and Human Activities

• Increased use of fossil fuels (CO2 , CH4)
• Deforestation (CO2 , N2O)
• Cultivation of Rice Patties (N2O)
• Global warming Enhanced greenhouse effect
• Melting icecaps and glaciers
• Coral reef bleaching
• Other

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Connections
Fossil fuels
Temperature
CO2
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Projecting Future Changes in Earths Climate

• Climate models(see Spotlight p. 457)

• Apparent influence of human activities

• Could be natural changes

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Factors Affecting Changes in Earths Average
Temperature

• Changes in solar output

• Changes in Earths albedo

• Moderating effect of oceans

• Clouds and water vapor

• Air pollution

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Six Degrees Could Change the World
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Some Possible Effects of a Warmer World

• Water Distribution
• Plant and Animal Biodiversity Loss
• Ocean Currents and Sea Levels
• Extreme Weather
• Human Population and Health
• Agriculture and Forests

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Some Possible Effects of a Warmer World
Fig. 18-16 p. 461
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Solutions Dealing with the Threat of Climate
Change
Options

• Do nothing

• Do more research

• Act now to reduce risks

• Act now no-regrets strategy

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Removing CO2 From the Atmosphere
Tree plantation
Coal power plant
Tanker delivers CO2 from plant to rig
Oil rig
CO2 is pumped down from rig for Deep ocean
disposal
Abandoned oil field
CO2 is pumped down to reservoir through
abandoned oil field
Crop field
Switchgrass field
Spent oil reservoir is used for CO2 deposit
Fig. 18-21 p. 467
CO2 deposit CO2 pumping
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Reducing Greenhouse Gas Emissions

• Rio Earth Summit (1992)
• 106 nations
• Scientific uncertainty must not be used as
  justification to do nothing.
• Industrialized nations must take lead in slowing
  down rate and degree of global warming.
• Developed countries voluntarily committed to
  reducing CO2 to 1990 levels by the year 2000

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Reducing Greenhouse Gas Emissions

• Kyoto Treaty (1997)
• 161 nations
• Required 38 developed countries to cut greenhouse
  emissions 5.2 below 1990 levels by 2012..
• Did not require developing countries to make
  cuts.
• Allowed emission trading among participating
  countries.
• Was not ratified until 2005
• Approximately 180 participating countries.

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United States did not ratify Kyoto Treaty -

1. Treaty fails to require emission reductions from
   developing countries (81 of worlds population)
2. Economists predicted it would have devastating
   impact on U.S. economy and workers

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Some U.S. CO2 Reductions

• Concern among leaders of some U.S. companies.
• Several major companies have established targets
  to reduce greenhouse gas emissions by 10-65 from
  1990 levels by 2010.
• Automobile companies investing in hybrid
  gas-electric and fuel cell engines.
• Local governments established programs to reduce
  greenhouse gas emissions.
• California first state to require a reduction in
  CO2 emissions from motor vehicles beginning in
  2009.

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A growing number of analysts suggest we should
begin to prepare for the possible effects of
long-term atmospheric warming and climate change!
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Ozone Depletion in the Stratosphere(the other
story)
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Stratosphere
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Benefical Ozone
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Stratospheric ozone
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Altitude (kilometers)
Altitude (miles)
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10
15
10
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Troposphere
Harmful Ozone
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0
0
0
5
10
15
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Ozone concentration (ppm)
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Ozone Depletion in the Stratosphere

• Importance of Ozone
• Essential for terrestrial life
• Reduces sunburn
• Prevents tropospheric ozone

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Ozone Depletion in the Stratosphere
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Ultraviolet light hits a chlorofluorocarbon (CFC)
molecule, such as CFCl3, breaking off a chlorine
atom and leaving CFCl2.
Once free, the chlorine atom is off to attack
another ozone molecule and begin the cycle again.
A free oxygen atom pulls the oxygen atom off
the chlorine monoxide molecule to form O2.
The chlorine atom attacks an ozone (O3) molecule,
pulling an oxygen atom off it and leaving an
oxygen molecule (O2).
The chlorine atom and the oxygen atom join to
form a chlorine monoxide molecule (ClO).
Stepped Art
Fig. 20-18, p. 486
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Ozone Depleting Chemicals

• Chlorofluorocarbons (CFCs)
• Methyl bromide (fumigant)
• Halons (fire extinguishers)
• Carbon tetrachloride (solvent)
• Methyl chloroform (cleaning solvent and
  propellant)
• N-propyl bromide (solvent)

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OZONE DEPLETION IN THE STRATOSPHERE

• During four months of each year up to half of the
  ozone in the stratosphere over Antarctica and a
  smaller amount over the Artic is depleted.

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Seasonal Thinning at the Poles

• Ozone thinning (hole)

• Polar vortex

Fig. 18-30 p. 475
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Reasons for Concern

• Increased incidence and severity of sunburn

• Increase in eye cataracts

• Increased incidence of skin cancer

• Immune system suppression

• Increase in acid deposition

• Lower crop yields and decline in productivity

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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.
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 A
Ultraviolet B
Thin layer of dead cells
Hair
Squamous cells
Epidermis
Basal layer
Sweat gland
Melanocyte cells
Dermis
Basalcell
Blood vessels
Squamous Cell Carcinoma
Melanoma
Basal Cell Carcinoma
Fig. 20-22, p. 489
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Solutions Protecting the Ozone Layer

• Use CFC substitutes

• Montreal Protocol (1987)
• only CFCs

• Copenhagen Protocol (1992)
• all ODCs

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Characteristics of Global Warming and Ozone
Depletion

• Global Warming
• CO2, CH4, NOx (greenhouse gases)
• Absorbs infrared (IR) radiation
• Raising the earths surface temperature
• Decrease burning of fossil fuels

• Ozone Depletion
• O3, O2, and CFCs
• Absorbs ultraviolet (UV) radiation
• Decreasing O3 concentration in the stratosphere
• Eliminate CFCs

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2007 FRQ 3