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Climate Change and Ozone Loss

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Climate Change and Ozone Loss G. Tyler Miller s Living in the Environment 13th Edition Chapter 18 – PowerPoint PPT presentation

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Title: Climate Change and Ozone Loss


1
Climate Change and Ozone Loss
G. Tyler Millers Living in the Environment 13th
Edition Chapter 18
2
Past Global Temperatures
3
Recent Trends in Global Temperature
4
Recent Trends in Global Temperature
5
Climate Change
  • Past global temperatures
  • Recent trends in global temperatures

6
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

7
The Natural Greenhouse Effect (tropospheric
heating effect)
8
Greenhouse Gases in the Largest Concentration
  • Water Vapor
  • Carbon Dioxide

9
Hydrologic (Water) Cycle
?
10
The Carbon Cycle (Terrestrial)
11
The Carbon Cycle (Aquatic)
12
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

13
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

14
Six Degrees Could Change the World
15
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

16
Some Possible Effects of a Warmer World
Fig. 18-16 p. 461
17
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
18
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

19
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.

20
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

21
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.

22
A growing number of analysts suggest we should
begin to prepare for the possible effects of
long-term atmospheric warming and climate change!
23
Ozone Depletion in the Stratosphere (the other
story)
24
40
25
35
20
Stratosphere
30
Benefical Ozone
25
Stratospheric ozone
15
Altitude (kilometers)
Altitude (miles)
20
10
15
10
5
Troposphere
Harmful Ozone
5
0
0
0
5
10
15
20
Ozone concentration (ppm)
25
Ozone Depletion in the Stratosphere
  • Importance of Ozone
  • Essential for terrestrial life
  • Reduces sunburn
  • Prevents tropospheric ozone

26
Ozone Depletion in the Stratosphere
27
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
28
Ozone Depleting Chemicals
  • Chlorofluorocarbons (CFCs)
  • Methyl bromide (fumigant)
  • Halons (fire extinguishers)
  • Carbon tetrachloride (solvent)
  • Methyl chloroform (cleaning solvent and
    propellant)
  • N-propyl bromide (solvent)

29
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.

30
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

31

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
32
Solutions Protecting the Ozone Layer
  • Use CFC substitutes
  • Montreal Protocol (1987)
  • only CFCs
  • Copenhagen Protocol (1992)
  • all ODCs

33
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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