Transcript 27. Global Warming

Global Warming
IB syllabus: 6.1.1-6.1.7
AP Syllabus
Ch 18
Video -
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http://wakeupfreakout.org/film/tippi
ng.html
Syllabus Statements
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6.1.1: Describe the role of greenhouse gasses in
maintaining mean global temperature.
6.1.2: Describe how human activities add to
greenhouse gasses.
6.1.3: Discuss qualitatively the potential effects of
increased mean global temperature
6.1.4: Discuss the feedback mechanisms that would
be associated with an increase in mean global
temperature
6.1.5: describe and evaluate pollution management
strategies to address the issue of global warming
6.1.6: Outline the arguments surrounding global
warming
6.1.7: Evaluate contrasting human perceptions of the
issue of global warming
vocabulary
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Correlation
Global warming
Greenhouse gases
Negative feedback
Positive feedback
Climate Change
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Global climate change is a fact of
earth’s history
Prolonged periods of global cooling &
global warming over past 900,000
years
Glacial periods followed by warmer
interglacial periods
Even in stable times regional changes
in climate occur on regional scale
Evidence includes – historical records,
tree rings, pollen, radioisotopes
Average surface temperature (°C)
Average temperature over past 900,000 years
17
16
15
14
13
12
11
10
9
900
800
700
600
500
400
300
Thousands of years ago
200
100
Present
Temperature change over past 22,000 years
2
Temperature change (°C)
Agriculture established
1
0
-1
-2
End of
last ice
age
-3
Average temperature over past
10,000 years = 15°C (59°F)
-4
-5
20,000
10,000
2,000
1,000
Years ago
200
100
Now
Temperature change over past 1,000 years
Temperature change (°C)
1.0
0.5
0.0
-0.5
-1.0
1000 1100 1200 1300 1400 1500 1600 1700
Year
1800 1900 2000 2101
Average surface temperature (°C)
Average temperature over past 130 years
15.0
14.8
14.6
14.4
14.2
14.0
13.8
13.6
1860
1880
1900
1920
1940
Year
1960
1980
2000
2020
The Natural Greenhouse effect
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Balance heat moving in & out of atmosphere
Keep constant moderate average
temperature normal & necessary for life
Greenhouse gas molecules trap energy as IR
radiation and heat lower atmosphere
• Gasses = water, methane & carbon
dioxide
• Water relatively constant, CO2 fluctuates
Really a tropospheric heating effect
With natural cooling average global temp =
59 ˚F
CO2 effects
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Past CO2 levels determined from ice core
data – analyzing content of gas bubbles
trapped in different layers of glaciers
CO2 has varied historically but is
peaking presently
Correlation between CO2 and
temperature has been show dating back
460,000 years
360
340
320
300
280
Carbon dioxide
260
240
220
+2.5
200
0
180
–2.5
–5.0
Temperature
change
End of
last ice age
160
120
80
40
0
Thousands of years before present
–7.5
–10.0
Variation of temperature (˚C)
from current level
Concentration of carbon dioxide
in the atmosphere (ppm)
380
Global Warming
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Since 1750, Industrial Revolution
• Sharp rise in fossil fuel use, landfills  CO2 &
CH3
• Deforestation, Clear & burn grasslands  CO2
& N2O
• Rice paddies, inorganic fertilizer use  N2O
Mostly cars (700 million) & coal power plants
Increased greenhouse gas from humans
• Enhance natural Greenhouse effect
• Raise average global temperature of
atmosphere near earth’s surface  Global
warming
This one is all ours - CFCs
Are we experiencing Global Warming?
There is no longer a question
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CO2 in troposphere highest in last 20
million years
20th century hottest in last 1000 years
Since 1861 average global temp has risen
0.74 +/- 0.18 ˚C
Shrinking of glaciers, melting of ice caps
10 – 20 cm rise in global sea level
Change of range of species, moving to
poles
Timing of seasons has changed
14.7
380
8.0
14.6
7.6
7.2
6.8
6.4
6.0
CO2 concentration (ppm)
375
14.5
Fossil fuels
14.4
365
Temperature
14.3
355
14.2
345
5.6
335
14.1
14.0
CO2
5.2
4.8
13.9
325
1970
13.8
1980
1990
Year
2000
2005
Temperature (Cº)
Fossil fuels burn
(billions of metric tons of oil equivalent)
8.4
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Evidence shows correlation not causation
Could be natural climate fluctuation
Could be global warming
Could be a combination of both
Remember that in all peer reviewed
articles on the subject there is no question
that this is a reality
Effects of Rapid Climate Change
Affect water availability, altering
precipitation & evaporation patterns
2. Shift areas where crops will grow
3. Change average sea levels
4. Alter the structure & location of the
world’s biomes
1.
Where can we see change?
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Antarctica: Surrounding ice cap
holds 70% world fresh water, 90%
reflective ice for cooling
Pieces the size of RI, CN are
breaking off
Arctic: Ocean surface temp rising
Greenland: 85% ice sheet coverage
+ closest to the equator
ºC
ºF
8
4
2
0
0
Projected
Year
2050
1
2025
4
2000
2
Global average
1975
6
1959
3
1950
Temperature
Arctic
Seals
Elephant
Weddell
Fur
Krill
Penguins
Emperor
Adélie
Petrels
concentrations
Average minimum
extent of summer icepack
Average maximum
event of winter
icepack
0
0
–130
250,000
–426
200,000
150,000
100,000
Years before present
If melting occurs…
50,000
0
Present
Height above or below
present sea level (feet)
Height above or below
present sea level (meters)
Today’s sea level
Can we project future changes?
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Scientists create climate models
GCM – general circulation model –
represents air circulation on earths surface
Also include: (1) ocean circulation, (2) air /
ocean circulation, (3) solar input, (4)
aerosols
IPCC – International Panel on Climate
Change (p 455 for results)
• Still debate on severity of the issue
• Agree that more research necessary to
improve models
Temperature Change (°C) from 1860-1999 mean
15.0
Observed
14.8
Model of greenhouse gasses
+ aerosols + solar output
1.0
0.8
0.6
0.2
0.0
-0.2
1860
1880
1900
1920
1940
Year
1960
1980
2000 2010
6.0
5.5
5.0
Change in temperature (ºC)
4.5
Models
Give
A Range
Of
Possibility
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0
1850 1875 1900 1925 1950 1975 2000 2025 2050 2075 2100
Year
What will effect continued climate
change?
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Natural & Human influenced factors
will effect the future of global climate
Factors may amplify current trends
 positive feedback
Factors may dampen current trends
 negative feedback
These factors could influence how
fast and how much temperatures
change
Also effect regional differences
Feedback (Remember the time lag)
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Positive
Increase Temp
Melt Permafrost
Increased release of
methane
Increase Temp more
Melt more
Permafrost…
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Negative
Increased Temp
Increased
evaporation in
Tropics
Increased snowfall in
poles
Increase icecap cover
Increased albedo
Decreased Temp
Factors Effecting Temperature
1.
2.
Solar output varies overtime
• May account for up to 50% of climate change
• Increase in cosmic rays may decrease
temperature, decrease in CR  increase temp.
• Pollutant effects may outweigh or reverse this
Ice albedo (reflectivity) feedback system
• Ice, snow, sand reflect most incoming sunlight
• Sea ice reflects 80%, water absorbs 80%
incoming solar radiation
• Positive ice albedo feedback system – increase
temp  melt ice  less albedo  increase
temp …
Clouds 50–55%
Snow 80–90%
City 10–15%
Forest 5%
Grass 15–25%
Bare sand 30–60%
Oceans 5%
Factors Effecting Temperature II
3.
Ocean effects
• Remove 29% of excess CO2 emissions
• Solubility decreases with increased temp.
• Atmospheric heat transferred into deep
ocean
• Ocean currents moderate global climate
 fresh water influx stops motion 
temperature drop will result
• Sea level changes effect amount of heat
and CO2 & earth’s biome distribution
• Thermal expansion of oceans possible too
Greenland
Antarctica
Vertical & Horizontal Water movement in the ocean
Factors Effecting Temperature III
4.
Clouds & Water Vapor content
• Warmer temp increases evaporation &
cloud cover
• Clouds have (1) warming effect by
trapping heat (positive feedback) or (2)
cooling effect by reflecting heat (negative
feedback)
• Depends on time of day, water content
and cloud type
• There is an effect but the degree is
uncertain
Human Factors I
1.
2.
Air Pollution
• Aerosols are condensation nuclei for clouds
• Input could either amplify or dampen GW
• Aerosols fall out of atmosphere & inputs are
being reduced
Increased CO2 levels
• Could lead to plant growth removing more CO2
• Plants take in less as they mature, upon death
they release it again
• CO2 is a greenhouse gas trapping more heat
• Soils may absorb some extra CO2
Human Factors II
3.
Greenhouse gas production
• Power production, Land clearing
practices, Transportation
• Regional input global distribution
• Lifestyle dependency on this process
What will happen
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Not a normal weather swing of a few degrees
this is GLOBAL CLIMATE CHANGE
Water distribution will change
Plant and animal distribution will change
Ocean currents & sea level will change
Extreme weather may develop – drought,
floods
Human health in older populations & urban
areas
• Less severe winters
• More precipitation in some dry areas
• Less precipitation in some wet areas
• Increased food production in some areas
• Expanded population and range for some plant
and animal species adapted to higher temperatures
Potential Benefits of Global Warming
Agriculture
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Shifts in food-growing
areas
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Changes in crop yields
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Increased irrigation
demands
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Increased pests, crop
diseases, and weeds in
warmer areas
Water Resources
• Changes in water supply
• Decreased water quality
• Increased drought
• Increased flooding
Forests
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Changes in forest
composition and locations
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Disappearance of some
forests
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Increased fires from drying
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Loss of wildlife habitat and
species
Biodiversity
Sea Level and Coastal Areas
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Extinction of some plant
and animal species
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Loss of habitats
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Disruption of aquatic life
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Weather Extremes
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Prolonged heat waves
and droughts
Increased flooding
from more frequent,
intense, and heavy
rainfall in some areas
Human Population
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• Increased deaths
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• More environmental
refugees
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• Increased migration
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Rising sea levels
Flooding of low-lying islands
and coastal cities
Flooding of coastal estuaries,
wetlands, and coral reefs
Beach erosion
Disruption of coastal
fisheries
Contamination of coastal
aquifiers with salt water
Human Health
Increased deaths from heat
and disease
Disruption of food and water
supplies
Spread of tropical diseases to
temperate areas
Increased respiratory disease
and pollen allergies
Increased water pollution
from coastal flooding
Effects on Distribution of Biomes
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Every 1 degree temp increase shifts
climate belts up 150 meters in altitude
& 100 km in latitude
Ranges of warm adapted plants and
animals may increase
Dispersal method may effect ability of
species to keep up with climate change
Extinction of plants and animals that
could not migrate – specialized species
decrease
Threaten existing wildlife reserves,
parks, wetlands & coral reefs
Wetter than now
Drier than now
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Global agricultural regions will
change characteristics
Decreased production in some areas
Present
range
Future
range
Overlap
Major urban region at risk
Islands at risk
What can you do in your own
life to effect local green
house emissions?
Local Emissions Reductions
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Waste less energy
Rely more on cleaner energy sources
Choose transportation wisely
Shifting to organic farming and
sustainable agriculture
Gradually integrate solutions to
decrease global warming, air
pollution, deforestation & biodiversity
loss
Type of Transportation
CO2 emissions per mile (pounds per passenger)
1.6 (0.45 kilograms
per kilometer)
Sports utility vehicle
(1 person, 15 mpg)
Average car
(1 person, 21.5 mpg)
1.1 (0.31 kilograms per kilometer)
0.97 (0.27 kilograms per kilometer)
Jet
(U.S average occupancy)
Mass transit
(1/4 full)
0.75 (0.21 kilograms per kilometer)
Economy car
(1 person, 40 mpg)
0.59 (0.71 kilograms per kilometer)
Intercity train
(U.S average occupancy)
0.45 (0.13 kilograms per kilometer)
Carpool
(3 people, 21.5 mpg)
0.37 (0.10 kilograms per kilometer)
Mass transit
(3/4 full)
Bike or walk
0.26 (0.07 kilograms per kilometer)
0
Action
Drive fuel-efficient
car, walk, bike,
car pool, and use
mass transit
Use energy-efficient
windows
Use energy-efficient
refrigerator
Insulate walls
and ceilings
Reduce garbage
by recycling
and reuse
Caulk and
weatherstrip
windows and doors
Insulate hot water
heater
Use compact
fluorescent bulbs
Set water heater
at no higher than
(120° F)
Wash laundry in
warm or cold water
Use low-flow
shower head
CO2 Reduction
9 kg (20 lbs)
per gallon of
gasoline saved
Up to 4,500 kg
(10,000 lbs) per year
Up to 1,400 kg
(3,000 lbs) per year
Up to 900 kg
(2,000 lbs) per year
450 kg (1,000 lbs)
for 25% less
garbage per year
Up to 450 kg
(1,000 lbs) per year
Up to 450 kg
(1,000 lbs) per year
230 kg (500 lbs)
per year per bulb
230 kg (500 lbs)
for each 6° C
(10° F) reduction
Up to 230 kg
(500 lbs) per year
for 2 loads a week
Up to 140 kg
(300 lbs) per year
Global Emissions Reduction
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Phase in output based carbon taxes & input
based energy taxes
Increase government subsidies for energy
efficiency & renewable energy technologies
Fund transfer to renewable fuels
Place global & national caps on emissions
levels
Sell & trade emissions credits on open market
Remove CO2 from atmosphere – tree planting
1997 – Kyoto agreement
Prevention
Cut fossil fuel
use (especially
coal)
Shift from coal
to natural gas
Transfer energy
efficiency and
renewable energy
technologies
to developing
countries
Cleanup
Remove CO2
from smokestack
and vehicle
Emissions
Store (sequester
CO2 by planting
trees)
Sequester CO2
underground
Improve energy
efficiency
Sequester CO2
in soil
Shift to
renewable
energy resources
Sequester CO2
in deep ocean
Reduce
deforestation
Limit urban spawl
Slow population
growth
The implications vary
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MEDCs
Stand to lose the
most economically
But have the
technology to
change
Also some of
biggest polluters
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LEDCs
Rapidly increasing
their contribution –
China & India
It’s their turn, why
should they curb
emissions
Cheaper energy like
coal is used – lack
technology for other
methods
Figure 18-21
Page 467
Tree
plantation
Coal
power plant
Tanker delivers
CO2 from plant
to rig
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
= CO2 deposit
= CO2 pumping
Oil rig
CO2 is
pumped down
from rig for deep
ocean disposal
If its inevitable how do we prepare?
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Necessary reduction in emission is
unlikely in needed time period
Need widespread change in
industry, energy, transportation &
lifestyles
We must begin to prepare for the
results of not changing in time…
Waste less water
Develop crops
that need less
water
Move hazardous material storage
tanks away from coast
Prohibit new construction on lowlying coastal areas
N
Stockpile 1 to 5 year
supply of key foods
Expand existing wildlife
reserves toward poles
S
Connect wildlife
reserves with corridors
So what’s the argument?
Realize even now there are
dissenters
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Based on
• The complexity of the problem
• The uncertainty of computer models
• The percieved potential harm that will
be caused economic cascade caused by
doing something about it
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But remember the precautionary
principle
• If an action is potentially harmful it is
the responsibility of the group causing
the harm to prove that it is not, rather
than those being harmed having to
prove that they are
• Better safe than sorry
Contribution to Global Total (1%)
United States
25.5%
China
11.2%
Russia
6.7%
5.1%
Japan
India
4.1%
Germany
3.9%
United Kingdom
2.6%
Canada
2.5%
Italy
2.0%
France
1.8%
Per Capita Emissions (metric tons)
United States
5.6%
Canada
4.9%
Australia
4.9%
Netherlands
4.1%
Belgium
3.7%
Germany
2.8%
Czech Republic
2.8%
Russia
2.7%
2.6%
United Kingdom
France
1.8%
What about Global Dimming?
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Reduction in the insolation of the earth’s
surface –post 9/11 evidence
Seen in 1960s-1990s
Caused by increase in anthropogenic
particulates like sulfate aerosols
When aerosol levels started to decline in
the 1990’s dimming switched to a
brightening trend
Can create a cooling effect to counter
global warming
Potential Engineering Solution for us
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You should be able to evaluate the
contrasting human perceptions on
this issue
Explore / defend your position based
on this evaluation
Remember your
choices will
determine our
future
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http://www.nola.com/coastal/
Losing Louisiana
XXX
114
Global
warming
potential
(GWP)
Field
type
14
Conventional
tillage
No-till
cultivation
Conservation
reserve
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