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Climate Change and Ozone Loss

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Title: Global Warming and Ozone Depletion Author: H Clark Last modified by: hclark Created Date: 6/13/2001 1:21:45 AM Document presentation format – PowerPoint PPT presentation

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Title: Climate Change and Ozone Loss


1
Climate Change and Ozone Loss
2
Key Concepts
  • Changes in Earths climate over time
  • Factors affecting climate
  • Possible effects of global warming
  • Adapting to climate change
  • Human impacts on the ozone layer
  • Protecting and restoring the ozone layer

3
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4
Past Climate Changes
  • Past global temperatures
  • Recent trends in global temperatures

5
Temperature change over past 22,000 years
2
1
0
-1
End of last ice age
Temperature change (C)
-2
-3
-4
-5
20,000
10,000
2,000
1,000
200
100
Now
Years ago
6
Temperature change over past 1,000 years
1.0
0.5
0.0
Temperature change (C)
-0.5
-1.0
1000
1100
1200
1300
1400
1500
1600
1700
1800
1900
2000
2101
Year
7
Average temperature over past 130 years
15.0
14.8
14.6
14.4
Average surface temperature (C)
14.2
14.0
13.8
13.6
1860
1880
1900
1920
1940
1960
1980
2000
2020
Year
8
The Greenhouse Effect
  • Greenhouse effect
  • Greenhouse gases

9
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
10
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11
380
360
340
320
300
Concentration of carbon dioxide in the atmosphere
(ppm)
280
Carbon dioxide
260
240
2.5
220
0
200
Variation of temperature (C) from current level
2.5
180
5.0
7.5
Temperature change
10.0
End of last ice age
160
120
80
40
0
Thousands of years before present
12
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13
410
360
Parts per million
310
260
1800
1900
2000
2100
Year
Carbon dioxide (CO2)
14
2.4
1.8
Parts per million
1.2
0.6
1800
1900
2000
2100
Year
Methane (CH4)
15
320
310
Parts per million
300
290
260
1800
1900
2000
2100
Year
Nitrous oxide (N2O)
16
Climate Change and Human Activities
  • Increased use of fossil fuels
  • Deforestation
  • Global warming
  • Melting icecaps and glaciers
  • Rising sea level

17
Table 21-2 Major Characteristics of Global
Warming and Ozone Depletion
Characteristic Region of atmosphere
involved Major substances involved Interaction
with radiation Nature of
problem Possible consequences Possible
responses
Ozone Depletion Stratosphere. O3, O2,
chlorofluorocarbons (CFCs). About 95 of
incoming ultraviolet (UV) radiation from the sun
is absorbed by O3 molecules in the stratosphere
and does not reach the earths surface. CFCs
and other ozone-depleting chemicals released into
the troposphere by human activities have made
their way to the stratosphere, where they
decrease O3 concentration. This can allow more
harmful UV radiation to reach the earths
surface. Increased incidence of skin cancer,
eye cataracts, and immune system suppression and
damage to crops and phytoplankton. Eliminate or
find acceptable substitutes for CFCs and other
ozone-depleting chemicals.
Global Warming Troposphere. CO2, CH4, N2O
(greenhouse gases). Molecules of greenhouse
gases absorb infrared (IR) radiation from the
earths surface, vibrate, and release
longer-wavelength IR radiation (heat) into the
lower troposphere. This natural greenhouse effect
helps warm the lower troposphere. There is a
high (9099) probability that increasing
concentrations of greenhouse gases in the
troposphere from burning fossil
fuels,deforestation, and agriculture are
enhancing the natural greenhouse effect and
raising the earths average surface temperature
(Figure 21-2, bottom right, and Figure 21-11, p.
471). Changes in climate, agricultural
productivity, water supplies, and sea
level. Decrease fossil fuel use and
deforestation prepare for climate change.
18
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19
Greenland
20
Grass 1525
Bare sand 3060
Oceans 5
21
Todays sea level
0
0
Height above or below present sea level (feet)
Height above or below present sea level (meters)
130
426
250,000
200,000
150,000
100,000
50,000
0
Years before present
Present
22
Projecting Future Changes in Earths Climate
  • Climate models
  • Apparent influence of human activities
  • Could be natural changes

23
Troposphere
Cooling from increase
CO2 removal by plants and soil organisms
CO2 emissions from land cleaning, fires, and decay
Warming from decrease
Aerosols
Heat and CO2 removal
Heat and CO2 emissions
Greenhouse gases
Ice and snow cover
Shallow ocean
Land and soil biota
Long-term storage
Natural and human emissions
Deep ocean
24
Clouds
Land
Ocean
25
6.0
5.5
5.0
4.5
4.0
3.5
3.0
Change in temperature (ºC)
2.5
2.0
1.5
1.0
0.5
0
1850
1875
1900
1925
1950
1975
2000
2025
2050
2075
2100
Year
26
Factors Affecting the Earths Temperature
  • Changes in solar output
  • Changes in Earths albedo
  • Moderating effect of oceans
  • Clouds and water vapor
  • Air pollution

27
Antarctica
28
Some Possible Effects of a Warmer World
29
Possible Benefits from a Warmer Atmosphere
  • Less severe winters
  • More precipitation in some dry areas
  • Less precipitation in some wet areas
  • Increased food production in some areas
  • Expanded population and ranges of some species

30
Present range
Future range
Overlap
31
100
90
80
70
60
High Projection Shanghai, New Orleans, and other
low-lying cities largely underwater
Mean Sea-Level Rises (centimeters)
50
40
30
Medium Projection More than a third of
U.S. wetlands underwater
20
10
Low Projection
0
2010
2020
2030
2040
2050
2060
2070
2080
2090
2100
Year
32
Coal power plant
Tanker delivers CO2 from plant to rig
Oil rig
Tree plantation
CO2 is pumped down from rig for deep ocean
disposal
Abandoned oil field
Crop field
Switchgrass
CO2 is pumped down to reservoir through
abandoned oil field
Spent oil reservoir is used for CO2 deposit
CO2 deposit CO2 pumping
33
What Can You Do?
Reducing CO2 Emissions
  • Drive a fuel-efficient car, walk, bike, carpool,
  • and use mass transit
  • Use energy-efficient windows
  • Use energy-efficient appliances and lights
  • Heavily insulate your house and seal all drafts
  • Reduce garbage by recycling and reuse
  • Insulate hot water heater
  • Use compact fluorescent bulbs
  • Plant trees to shade your house during summer
  • Set water heater no higher than 49C (120F)
  • Wash laundry in warm or cold water
  • Use low-flow shower head

34
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35
Solutions Dealing with the Threat of Climate
Change
Options
  • Do nothing
  • Do more research
  • Act now to reduce risks
  • Precautionary principle

36
Solutions
Global Warming
Prevention
Cleanup
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
Shift to renewable energy resources
Sequester CO2 deep underground
Transfer energy efficiency and renewable energy
technologies to developing countries
Sequester CO2 in soil by using no-till
cultivation and taking crop land out of production
Reduce deforestation
Sequester CO2 in the deep ocean
Use more sustainable agriculture
Repair leaky natural gas pipelines and facilities
Limit urban sprawl
Reduce poverty
Use feeds that reduce CH4 emissions by belching
cows
Slow population growth
37
Reducing Greenhouse Gas Emissions
  • Kyoto Treaty (1997)
  • U.S. withdraws from Kyoto Treaty (2001)
  • Other reductions in CO2

38
Loss of the Ozone Layer 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

39
When did it all begin?
  • Dramatic loss of ozone in the lower stratosphere
    over Antarctica was first noticed in the 1970s by
    a research group.
  • They were monitoring the atmosphere above
    Antarctica from a research station

40
Research Station in Antarctica
41
The Atmosphere

42
Where and how ozone is formed?
  • Ozone (O3) forms a layer in the stratosphere,
    thinnest in the tropics (around the equator) and
    denser towards the poles.
  • It is created when ultraviolet radiation
    (sunlight) strikes the stratosphere, dissociating
    (or "splitting") oxygen molecules (O2) to atomic
    oxygen (O).
  • The atomic oxygen quickly combines with further
    oxygen molecules to form ozone (O3 )

43
Where is the Ozone hole ?
  • Over Antarctica (and recently over the Arctic),
    stratospheric ozone has been depleted at certain
    times of the year.
  • This is mainly due to the release of man-made
    chemicals containing chlorine such as CFC's
    (Chlorofluorocarbons), but also compounds
    containing bromine, other related halogen
    compounds and also nitrogen oxides (NOx).

44
Ozone Depleting Chemicals
  • Chlorofluorocarbons (CFCs)
  • Halons
  • Methyl bromide
  • Carbon tetrachloride
  • Methyl chloroform
  • Hydrogen chloride

45
Former Uses of CFCs
  • Air Conditioners
  • Refrigerators
  • Spray cans
  • Cleaners for electronic parts
  • Sterilizing medical instruments
  • Fumigants for granaries and cargo ships

46
CFCs in the air
47
Ozone Depletion in the Stratosphere
48
Ultraviolet light hits a chlorofluorocarbon
(CFC) molecule, such as CFCl3, breaking off a
chlorine atom and leaving CFCl2.
Sun
Cl
Cl
C
Once free, the chlorine atom is off to attack
another ozone molecule and begin the cycle again.
Cl
F
UV radiation
Cl
Cl
O
O
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).
Cl
Cl
O
O
O
O
O
Cl
The chlorine atom and the oxygen atom join to
form a chlorine monoxide molecule (ClO).
O
O
O
49
Seasonal Ozone Layer Thinning at the Poles
  • Ozone thinning (hole)
  • Polar vortex

50
January 1995 October 1995
51
Its getting bigger..
  • Satellite measurements in September 2000 revealed
    that the stratospheric ozone hole over the
    Antarctic had a reached a record 28.3 million
    square kilometers (some one million sq. km more
    than the previous record, in 1998).

52
October 1980- October 2002
53
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54
35
August 6, 2003
30
October 11, 2003
25
20
Altitude (kilometers)
15
10
5
0
5
10
15
Ozone partial pressure (milipascals)
55
Natural Capital Degradation
Effects of Ozone Depletion
  • Human Health
  • Worse sunburn
  • More eye cataracts
  • More skin cancers
  • Immune system suppression
  • Food and Forests
  • Reduced yields for some crops
  • Reduced seafood supplies from reduced
    phytoplankton
  • Decreased forest productivity for UV-sensitive
    tree species
  • Wildlife
  • Increased eye cataracts in some species
  • Decreased population of aquatic species
    sensitive to UV radiation
  • Reduced population of surface phytoplankton
  • Disrupted aquatic food webs from reduced
    phytoplankton
  • Air Pollution and Materials
  • Increased acid deposition

56
What are some of the dangers associated with the
ozone hole?
  • Experts predict that an estimated 10 reduction
    in the ozone layer will result in a 25 increase
    in non-melanoma skin cancer rates for temperate
    latitudes by the year 2050.

57
Skin Cancers
Melanoma
Squamous Cell Carcinoma
Basal Cell Carcinoma
58
Ultraviolet A
Ultraviolet B
Thin layer of dead cells
Hair
Epidermis
Squamous cells
Basal layer
Sweat gland
Melanocyte cells
Dermis
Basal cell
Blood vessels
Squamous Cell Carcinoma
Basal Cell Carcinoma
Melanoma
59
What Can You Do?
Reducing Exposure to UV-Radiation
  • Stay out of the sun, especially between 10 A.M.
    and 3 P.M.
  • Do not use tanning parlors or sunlamps.
  • When in the sun, wear protective clothing and
    sun
  • glasses that protect against UV-A and UV-B
    radiation.
  • Be aware that overcast skies do not protect you.
  • Do not expose yourself to the sun if you are
    taking antibiotics or birth control pills.
  • Use a sunscreen with a protection factor of 15 or
    25 if
  • you have light skin.
  • Examine your skin and scalp at least once a month
    for moles or warts that change in size, shape, or
    color or sores that keep oozing, bleeding, and
    crusting over. If you observe any of these signs,
    consult a doctor immediately.

60
Skin Cancer Fact Sheet
  • Over half of all new cancers are skin cancers.  
  • More than 1 million new cases of skin cancer will
    be diagnosed in the United States this year.  
  •    An estimated 10,250 people will die of skin
    cancer this year.
  •   One person dies of melanoma every hour. 

61
More Facts
  • At current rates one in 37 Americans have a
    lifetime risk of developing melanoma and one in
    65 Americans have a lifetime risk of developing
    invasive melanoma.
  • The incidence of melanoma more than tripled among
    Caucasians between 1980 and 2003.  
  • More than 77 percent of skin cancer deaths are
    from melanoma.

62
Solutions Protecting the Ozone Layer
  • CFC substitutes
  • Montreal Protocol
  • Copenhagen Protocol

63
15,000
No protocol
12,000
1987 Montreal Protocol
9,000
Abundance (parts per trillion)
6,000
1992 Copenhagen Protocol
3,000
0
1950
1975
2000
2025
2050
2075
2100
Year
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