Climate Change and Ozone Loss. Key Concepts Changes in Earth’s climate over time Factors...
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Transcript of Climate Change and Ozone Loss. Key Concepts Changes in Earth’s climate over time Factors...
Climate Change and Ozone LossClimate Change and Ozone Loss
Key ConceptsKey Concepts
Changes in Earth’s climate over time Changes in Earth’s climate over time
Factors affecting climate Factors affecting climate
Possible effects of global warming Possible effects of global warming
Adapting to climate change Adapting to climate change
Human impacts on the ozone layer Human impacts on the ozone layer
Protecting and restoring the ozone layer Protecting and restoring the ozone layer
Past Climate ChangesPast Climate Changes
Past globaltemperatures
Past globaltemperatures
Recent trends in global temperatures
Recent trends in global temperatures
Temperature change over past 22,000 years
Years ago
Tem
per
atu
re c
han
ge
(°C
)
20,000 10,000 2,000 1,000 200 100 Now
-5
-4
-3
-2
-1
0
1
2
End oflast iceage
Agriculture established
Average temperature over past10,000 years = 15°C (59°F)
Temperature change over past 1,000 years
Year
Tem
per
atu
re c
han
ge
(°C
)
1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 2000 2101
-1.0
-0.5
0.0
0.5
1.0
Average temperature over past 130 years
Year
Ave
rag
e su
rfac
e te
mp
erat
ure
(°C
)
1860 1880 1900 1920 1940 1960 1980 2000 2020
13.6
13.8
14.0
14.2
14.4
14.6
14.8
15.0
The Greenhouse EffectThe Greenhouse Effect
Greenhouse effect Greenhouse effect Greenhouse gases Greenhouse gases
Table 21-1 Major Greenhouse Gases from Human Activities
Greenhouse Gas
Carbon dioxide (CO2)
Methane (CH4)
Nitrous oxide (N2O)
Chlorofluorocarbons(CFCs)*
Hydrochloro-fluorocarbons (HCFCs)
Hydrofluorocarbons(HFCs)
Halons
Carbon tetrachloride
Average Time in the Troposphere
100–120 years
12–18 years
114–120 years
11–20 years (65–110 years in stratosphere)
9–390
15–390
65
42
Human Sources
Fossil fuel burning, especially coal (70–75%), 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
900–8,300
470–2,000
130–12,700
5,500
1,400
Carbon dioxide
Temperaturechange End of
last ice age
160 120 80 40 0Thousands of years before present
Co
nc
entr
ati
on
of
carb
on
dio
xid
ein
th
e a
tmo
sph
ere
(p
pm
)
180
200
220
240
260
280
300
320
340
360
380
–10.0
–7.5
–5.0
–2.5
0
+2.5
Va
riat
ion
of
tem
pe
ratu
re (
˚C)
fro
m c
urr
en
t le
vel
Carbon dioxide (CO2)
Year1800 1900 2000 2100
260
310
360
410P
arts
per
mil
lio
n
Methane (CH4)
Year
1800 1900 2000 21000.6
1.2
1.8
2.4P
arts
per
mil
lio
n
Year
Par
ts p
er m
illi
on
1800 1900 2000 2100260
290
300
310
320
Nitrous oxide (N2O)
Climate Change and Human ActivitiesClimate Change and Human Activities
Increased use of fossil fuelsIncreased use of fossil fuels
Deforestation Deforestation
Global warmingGlobal warming
Melting icecaps and glaciersMelting icecaps and glaciers
Rising sea levelRising sea level
Table 21-2 Major Characteristics of Global Warming and Ozone Depletion
Characteristic
Region ofatmosphere involved
Majorsubstances 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 O3molecules in the stratosphere and does not reach the earth’s 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 earth’s surface.
Increased incidence of skin cancer, eyecataracts, 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 earth’s 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 (90–99%) 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 earth’s 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.
Greenland
Oceans 5%
Bare sand 30–60%
Grass 15–25%
Clouds 50–55%
Snow 80–90%
City 10–15%
Forest 5%
Today’s sea level
Years before present Present
250,000 200,000 150,000 100,000 50,000 0
–130
0
–426
0
Hei
gh
t ab
ove
or
bel
ow
pre
sen
t se
a le
vel
(met
ers)
Hei
gh
t ab
ove
or
bel
ow
p
rese
nt
sea
leve
l (f
eet)
Projecting Future Changes in Earth’s ClimateProjecting Future Changes in Earth’s Climate
Climate modelsClimate models
Apparent influence of human activitiesApparent influence of human activities
Could be natural changesCould be natural changes
Troposphere
Aerosols
Greenhousegases
Warmingfromdecrease
Cooling from increase
CO2 removal by plants and soil organisms
CO2 emissions from land cleaning, fires, and decay
Heat andCO2 removal
Heat andCO2 emissions
Ice and snow cover
Natural and human emissions
Land and soil biota
Shallow ocean
Long-termstorage
Deep ocean
Cell
Clouds
OceanLand
Year
0
1850 1875 1900 1925 1950 1975 2000 2025 2050 2075 2100
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
6.0
Ch
ang
e i
n t
em
pe
ratu
re (
ºC)
Factors Affecting the Earth’s TemperatureFactors Affecting the Earth’s Temperature
Changes in solar outputChanges in solar output
Changes in Earth’s albedoChanges in Earth’s albedo
Moderating effect of oceansModerating effect of oceans
Clouds and water vaporClouds and water vapor
Air pollutionAir pollution
Antarctica
GreenlandGreenland
Some Possible Effects of a Warmer WorldSome Possible Effects of a Warmer World
Possible Benefits from a Warmer AtmospherePossible Benefits from a Warmer Atmosphere
Less severe wintersMore precipitation in some dry areasLess precipitation in some wet areasIncreased food production in some areasExpanded population and ranges of some
species
Less severe wintersMore precipitation in some dry areasLess precipitation in some wet areasIncreased food production in some areasExpanded population and ranges of some
species
Presentrange
Futurerange
Overlap
Year
02010 2020 2030 2040 2050 2060 2070 2080 2090 2100
10
20
30
40
50
60
70
80
90
100
Mea
n S
ea-
Le
vel
Ris
es (
cen
tim
eter
s)
High ProjectionShanghai, New Orleans,and other low-lying citieslargely underwater
Medium ProjectionMore than a third of U.S.
wetlands underwater
Low Projection
Treeplantation
Coalpower plant
Tanker deliversCO2 from plantto rig
Oil rig
Crop fieldSwitchgrass
Spent oil reservoir isused for CO2 deposit
CO2 is pumpeddown to reservoir through abandoned oil field
Abandonedoil field
CO2 ispumped downfrom rig for deepocean disposal
= CO2 deposit
= CO2 pumping
Reducing CO2 Emissions
What Can You Do?
• 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 49°C (120°F)
• Wash laundry in warm or cold water
• Use low-flow shower head
Solutions: Dealing with the Threat of Climate ChangeSolutions: Dealing with the Threat of Climate Change
OptionsOptions
Do nothing Do nothing
Do more research Do more research
Act now to reduce risks
Act now to reduce risks
Precautionary principle
Precautionary principle
Global Warming
Solutions
Prevention Cleanup
Cut fossil fuel use (especially coal)
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
Limit urban sprawl
Reduce poverty
Slow population growth
Store (sequester) CO2 by planting trees
Sequester CO2 deep underground
Sequester CO2 in soil by using no-till cultivation and taking crop land out of production
Sequester CO2 in the deep ocean
Repair leaky natural gas pipelines and facilities
Use feeds that reduce CH4 emissions by belching cows
Remove CO2 from smokestackand vehicle emissions
Reducing Greenhouse Gas EmissionsReducing Greenhouse Gas Emissions
Kyoto Treaty (1997) Kyoto Treaty (1997)
Other reductions in CO2 Other reductions in CO2
U.S. withdraws from Kyoto Treaty (2001) U.S. withdraws from Kyoto Treaty (2001)
Loss of the Ozone Layer: Reasons for ConcernLoss of the Ozone Layer: Reasons for Concern
Increased incidence and severity of sunburn Increased incidence and severity of sunburn
Increase in eye cataracts Increase in eye cataracts
Increased incidence of skin cancer Increased incidence of skin cancer
Immune system suppression Immune system suppression
Increase in acid deposition Increase in acid deposition
Lower crop yields and decline in productivity Lower crop yields and decline in productivity
When did it all begin?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
Research Station in AntarcticaResearch Station in Antarctica
The AtmosphereThe Atmosphere
•
Where and how ozone is formed?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 )
Where is the Ozone “hole” ?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).
Ozone Depleting ChemicalsOzone Depleting Chemicals
Chlorofluorocarbons (CFCs) Chlorofluorocarbons (CFCs)
Halons Halons
Methyl bromide Methyl bromide
Carbon tetrachloride Carbon tetrachloride
Methyl chloroform Methyl chloroform
Hydrogen chloride Hydrogen chloride
Former Uses of CFCsFormer Uses of CFCs
Air Conditioners
Refrigerators
Spray cans
Cleaners for electronic parts
Sterilizing medical instruments
Fumigants for granaries and cargo ships
Air Conditioners
Refrigerators
Spray cans
Cleaners for electronic parts
Sterilizing medical instruments
Fumigants for granaries and cargo ships
CFC’s in the airCFC’s in the air
Ozone Depletion in the StratosphereOzone Depletion in the Stratosphere
Ultraviolet light hits a chlorofluorocarbon (CFC) molecule, such as CFCl3, breakingoff a chlorine atom and leaving CFCl2.
UV radiation
Sun
Once free, the chlorine atom is off to attack another ozone moleculeand begin the cycle again.
A free oxygen atom pulls the oxygen atom off the chlorine monoxide molecule to form O2.
The chlorine atom and the oxygen atom join to form a chlorine monoxide molecule (ClO).
The chlorine atom attacksan ozone (O3) molecule, pulling an oxygen atom off it and leaving an oxygen molecule (O2).
Cl
Cl
ClC
F
Cl
Cl
OO
Cl
OO
O
Cl
O
OO
ClO
O
Summary of ReactionsCCl3F + UV Cl + CCl2FCl + O3 ClO + O2
Cl + O Cl + O2
Repeated many times
Seasonal Ozone Layer Thinning at the PolesSeasonal Ozone Layer Thinning at the Poles
Ozone thinning (hole)Ozone thinning (hole)
Polar vortexPolar vortex
January 1995 October 1995January 1995 October 1995
It’s getting bigger……..It’s 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).
October 1980- October 2002 October 1980- October 2002
Year
1970 1975 1990 2000 200519851955 1960 1965 1980 1995
400
350
300
250
200
150
100
To
tal o
zon
e (D
ob
son
un
its)
October monthly means
August 6, 2003
October 11, 2003
35
30
25
20
15
10
5
0 5 10 15Ozone partial pressure (milipascals)
Alt
itu
de
(kil
om
eter
s)
Effects of Ozone Depletion
Natural Capital Degradation
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• Increased photochemical smog• Degradation of outdoor paints and plastics
Global Warming• Accelerated warming because of decreased ocean uptake of CO2
from atmosphere by phytoplankton and CFCs acting as greenhouse gases
What are some of the dangers associated with the ozone hole?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.
Skin CancersSkin Cancers
Squamous Cell Carcinoma
Melanoma
Basal Cell Carcinoma
Ultraviolet A Ultraviolet B
Thin layer ofdead cells
Squamouscells
Basallayer
Melanocytecells
Basalcell
Bloodvessels
HairEpidermis
Sweatgland
Dermis
Squamous Cell Carcinoma Basal Cell Carcinoma Melanoma
Reducing Exposure to UV-Radiation
What Can You Do?
• 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 ifyou 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.
Skin Cancer Fact SheetSkin 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.
More FactsMore 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.
Solutions: Protecting the Ozone LayerSolutions: Protecting the Ozone Layer
CFC substitutes CFC substitutes
Montreal Protocol Montreal Protocol
Copenhagen Protocol Copenhagen Protocol
Year
1950 1975 2000 2025 2050 2075 2100
3,000
0
6,000
9,000
12,000
15,000
Ab
un
da
nc
e (p
art
s p
er
trill
ion
)
No protocol
1987MontrealProtocol
1992CopenhagenProtocol