1. Chapter 21: Climate Change
Global Change Unit

2. Past climates Global cooling and warming occur in cycles
Glacial and interglacial periods
Glacial periods last about 100,000 years.
Interglacial last about 10,000-12,500 years.
Our current interglacial age has lasted about 12,000 years…

3. Glacial and Interglacial Periods
Average temperature over past 900,000 years 17 16 15 14
Average surface temperature (°C) 13 12 11 10 9
900
800
700
600
500
400
300
200
100
Present
Thousands of years ago
Glacial and Interglacial Periods

4. Temperature change over past 22,000 years
Agriculture established 1
Average temperature over past
10,000 years = 15°C (59°F) -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
Past 22,000 years

5. Temperature change over past 1,000 years Temperature change (°C)
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
Past 1,000 years

6. Past 130 years 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
Past 130 years

7. Ice can tell us WHAT?
Past climate information is found through ice cores from Antarctica and Greenland.
The ice core (see fig 21.3) can tell us:
Greenhouse gas concentrations
Solar activity
Snowfall
Forest fires (layers of soot)
Core samples from lakes/ponds bottom tell us:
Pollen
Fossils
Plant life
Growth trends

8. Too much information!! What we do with all that information:
IPCC: Intergovernmental Panel on Climate Change
2,000 experts from 70 nations
IPCC uses probability to describe trends:
Virtually certain: more than 99% probability
Very likely: 90-99% probability
Likely: 66-90% probability
Our current interglacial age is likely to last another 15,000 years

9. Pink vs. Blue
Various regions of the world all show warming trends over the past 100 years. These graphs compare the observed changes in temperature (black lines) with model results that include only natural climate forcings like volcanic eruptions and changes in solar energy (blue) and model results that use both natural and human caused climate forcings (pink).

10. Greenhouse Effect

11. What’s happening here?
More greenhouse gases in the air, prevents heat moving out of the atmosphere. Added greenhouse gases absorb the heat.

12. Greenhouse Effect
                                                
Heat is “trapped” inside the atmosphere much like heat is trapped in a greenhouse.
What causes the “trapping”?
Carbon Dioxide
Methane
NOx
CFC’s
HCFC’s
Halons
Water vapor (hasn’t changed – closed system)
CF4
This animation shows how a carbon dioxide molecule vibrates when it absorbs heat.

13. Greenhouse Effect
Heat is “trapped” inside the atmosphere much like heat is trapped in a greenhouse.
What causes the “trapping”
Carbon Dioxide
Methane
NOx
CFC’s
HCFC’s view clip
Halons
Water vapor (hasn’t changed – closed system)
CF4

14. Effects to think about Increased death from heat, malnutrition
Very likely (90-99%) that tree deaths from disease and pests will increase
Very likely that wildfires will increase
Loss of animals and plants that can’t migrate quickly enough
Increase in pest (high tolerance) animals and insects
Tree species would move toward polar regions (5 miles per decade now)
Increased hurricanes (over warmer water)

15. CO2 effects 380 360 340 320 300 Concentration of carbon dioxide
in the atmosphere (ppm)
280
Carbon dioxide
260
240
+2.5
220
200
Variation of temperature (˚C)
from current level
180
–2.5
–5.0
–7.5
Temperature
change
End of
last ice age
–10.0
160
120 80 40
Thousands of years before present

16. Where’s all this gas from?
Burning of fossil fuels (CO2 )
Deforestation (CO2)
Clearing and burning grasslands (CO2)
Larger cattle herds (CH4)
Rice paddies/fertilizers (Nox and CH4 )
Automobiles (1 gallon of gas = 20 lbs. of CO2 ; one tank of gas = 360 lbs. of CO2)

17. Dirty, Rotten Americans!
#1 producer of CO2 emissions (24% of world’s emissions)
CO2 emissions from our cars is more than the emissions of everything that powers Japan!
Each American produces more CO2 than any other nations individuals (per capita). 500 tons of CO2 in your lifetime!
Huge amounts of methane from landfills and livestock.

18. The graphs say it all

19. Carbon dioxide (CO2) 410 360 Parts per million 310 260 1800 1900 2000
2100
Year
Carbon dioxide (CO2)

20. Methane (CH4) 2.4 1.8 Parts per million 1.2 0.6 1800 1900 2000 2100
Year
Methane (CH4)

21. Nitrous oxide (N2O) 320 310 Parts per million 300 290 260 1800 1900
2000
2100
Year
Nitrous oxide (N2O)

22. Global Warming vs Climate Change
Global warming: trend towards increasing temperatures. 10 warmest years on record have occurred since 1990.
Global climate change: changes in precipitation, temperatures, storm intensity. Global warming can lead to global climate change.

23. Where’s the proof baby?

24. “Proof” of Global Warming
20th century was hottest on record
Since 1861, average global temperature has risen between 1o- 1.4o F (most of that has been since 1980)
16 hottest years on record have been since 1980, 10 hottest have been since 1990.
Glaciers and sea ice are shrinking.
Sea level rising (4 to 8 inches)

25. 1979
2003
Arctic Sea Ice Changes

26. Factors Affecting Earth’s Temperature
Oceans can store heat and CO2, but no one knows how much.
Cloud cover: can warm by trapping and releasing heat or cool by reflecting heat back to space (albedo effect)!

27. Albedo is measured on a scale from 0-1(or sometimes as a %).
Very dark colors have an albedo close to 0 (or close to 0%).
Very light colors have an albedo close to 1 (or close to 100%).

28. Albedo is measured on a scale from 0-1(or sometimes as a %).
Forests have low albedo, near 0.15.
Snow and ice, have very high albedo, as high as 0.8 or 0.9, and reflect most of the solar energy that gets to them, absorbing very little

29. Factors Affecting Earth’s Temperature
Oceans can store heat and CO2, but no one knows how much.
Cloud cover: can warm by trapping and releasing heat or cool by reflecting heat back to space (albedo effect)!
Outdoor air pollution: aerosols can either warm or cool the atmosphere (much like clouds)
Stimulate photosynthesis: more CO2 can temporarily cause higher photosynthesis. Temporary because plants will “level off” and die, releasing their CO2
Methane trapped under ice is released when the ice melts.

30. 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
Reduce deforestation
Sequester CO2 in the deep ocean
Use more sustainable agriculture
Repair leaky natural gas pipelines and facilities
Slow population growth
Use feeds that reduce CH4 emissions by belching cows

31. What are things would you be willing to do around your house?

32. 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 49°C (120°F)
Wash laundry in warm or cold water
Use low-flow shower head

33. Is this a Review of the Air Pollution Chapter?

34. Ozone Depletion The culprits: The “hole”:
CFC’s: used as coolants (Freon). Are now being phased out.
Halons: in fire extinguishers
Hydrobromofluorocarbons
The “hole”:
More of a thinning.
August-November (late winter/spring) over Antarctica
Why: wind patterns bring pollutants up and polar vortex keeps them there.

35. 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
The chlorine
atom and the
oxygen atom join
to form a chlorine
monoxide molecule (ClO). Cl O
Summary of Reactions
CCl3F + UV Cl + CCl2F
Cl + O3 ClO + O2
Cl + O Cl + O2
Repeated
many times O O

36. Spring Ozone Measurements
Year
1970
1975
1990
2000
2005
1985
1955
1960
1965
1980
1995
400
350
300
250
200
150
100
Total ozone (Dobson units)
October monthly means
Spring Ozone Measurements

37. Ozone Depletion Solar Backscatter Ultraviolet (SBUV)
Total Ozone Mapping Spectrometer (TOMS) instruments

38. 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
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

39. Protocols

40. Protocols
Kyoto Protocol: 1997; Reduce greenhouse gases. (concern is global warming)
Montreal Protocol: 1987; Reduce use of CFC’s (concern is ozone depletion)
Copenhagen Protocol: 1992; Reduce ozone depleting chemicals (concern is ozone depletion)

41. Kyoto Protocol International agreement 1997 161 nations
Directs 39 countries to take steps to decrease greenhouse gas emissions.
Developing countries were not held to the same standards as developed ones.
2001: G.W. Bush withdrew the US from the agreement because of expense and the fact that developing countries like China and India weren’t held accountable.