1. Will Human-Induced Climate Change Destroy the World?
Global Warming
Will Human-Induced Climate Change Destroy the World?
By Rich Deem
Note: This slideshow is NOT meant to be printed. View in slideshow mode only because of extensive builds and animations. Go to the website for a printable copy. Requires PowerPoint 2003 or PowerPoint Viewer 2003.
This slideshow present an overview of global warming issues, last updated 8/11/2006. A more detailed analysis of global warming issues is available at including a printable PDF version. 

2. Introduction Is the world getting warmer?
If so, are the actions of mankind to blame for earth’s temperature increases?
What can/should be done about these issues?
Are the potential resolutions worth the cost to implement them?
In examining global warming, we will be looking at questions such as 
Is the world getting warmer? 
If so, are the actions of mankind to blame for earth’s temperature increases? 
What can or should be done about global warming? 
Are the potential resolutions to global warming worth the cost to implement them? 

3. History of Earth’s Climate
Earth formed ~4.6 billion years ago
Originally very hot
Sun’s energy output only 70% of present
Liquid water present ~4.3 billion years ago (zircon dating)
Much of earth’s early history erased during late heavy bombardment (~3.9 billion years ago)
This is a big picture examination of the earth’s climate 
The Earth was formed around 4.6 billion years ago 
And was originally very hot 
However, the Sun’s energy output was only 70% of what it is presently 
Liquid water was present on the surface around 4.3 billion years ago, according to zircon dating 
However, much of earth’s early history was erased during late heavy bombardment, which took place around 3.9 billion years ago 

4. History of Earth’s Climate
Life appeared ~3.8 billion years ago
Photosynthesis began billion years ago
Produced oxygen and removed carbon dioxide and methane (greenhouse gases)
Earth went through periods of cooling (“Snowball Earth”) and warming
Earth began cycles of glacial and interglacial periods ~3 million years ago
The first life forms appeared ~3.8 billion years ago 
Photosynthesis began billion years ago, 
which produced oxygen and removed carbon dioxide and methane, which are greenhouse gases, from the atmosphere 
As a result, the Earth went through periods of cooling, commonly referred to as “Snowball Earth” and subsequent warming 
Earth began its current cycles of glacial and interglacial periods around 3 million years ago 

5. Earth’s Temperature Solar Energy Solar Energy Sun
The temperature of the earth is directly related to the energy input from the Sun.  Some of the Sun’s energy is reflected by clouds.  Other is reflected by ice. The remainder is absorbed by the earth. 

6. Earth’s Temperature Solar Energy Radiative Cooling Sun
 If amount of solar energy absorbed by the earth is equal to the amount radiated back into space, the earth remains at a constant temperature. 

7. Solar Energy Earth’s Temperature Sun Radiative Cooling
 However, if the amount of solar energy is greater than the amount radiated, then the earth heats up. 

8. Radiative Cooling Earth’s Temperature Sun Solar Energy
 If the amount of solar energy is less than the amount radiated, then the earth cools down. 

9. Sun
Greenhouse Effect
To a certain degree, the earth acts like a greenhouse.  Energy from the Sun penetrates the glass of a greenhouse and warms the air and objects within the greenhouse. The same glass slows the heat from escaping, resulting in much higher temperatures within the greenhouse than outside it. 

10. Earth’s Atmospheric Gases
Nitrogen (N2)
Non- Greenhouse
Gases
99%
Oxygen (O2)
Water (H2O)
Likewise, the earth’s atmospheric gases affect the ability of the earth to radiate the Sun’s energy back into space.  Nitrogen and  Oxygen  make up 99% of the earth’s atmospheric gases  and are non-greenhouse gases.  Water,  Carbon Dioxide,  and Methane  make up 1% of the earth’s atmosphere,  but are greenhouse gases, since they cause the earth to retain heat. 
Carbon Dioxide (CO2)
Greenhouse
Gases 1%
Methane (CH4)

11. Runaway Greenhouse Effect
Sun
Runaway Greenhouse Effect
Venus
97% carbon dioxide
3% nitrogen
Water & sulfuric acid clouds
Temperature: 860°F
A dramatic example of the Greenhouse effect can be seen with the planet Venus. Venus’s atmosphere consists of  97% carbon dioxide and  3% nitrogen. In addition, the surface is covered by  dense clouds of water and sulfuric acid. The combination of greenhouse gases results in a  surface temperature of 860°F – even hotter than the planet Mercury, which is nearest the Sun. 

12. Carbon Dioxide 

13. Carbon Dioxide Levels 420 370 320 CO2 (ppm) 270 220 170 600000 400000
Muana Loa Readings
CO2 Levels Since 1958
310
330
350
370 10 20 30 40
CO2 (ppm)
370
320
CO2 (ppm)
270
This graph shows the amount of  carbon dioxide in the atmosphere for the last 650,000 years, as determined through Antarctic ice cores.  You will notice the  large spike at the end of the graph, which can be seen in the  inset as a dramatic increase in atmospheric carbon dioxide over the last 45 years. 
220
Dome Concordia
Vostok Ice Core
170
600000
400000
200000
Time (YBP)

14. Worldwide Carbon Emissions8
Liquid fuel
Total
Gas fuel
Solid fuel 7 6 5
Carbon (109 metric tons) 4 3
This spike is due to the exponential increase in the use of fossil fuels over the last 150 years. Shown here are emissions of carbon from  gas,  solid,  liquid fuels, and  the total carbon emissions.  2 1
1750
1800
1850
1900
1950
2000
Year

15. Annual Carbon Emissions8
Annual carbon emissions
Atmospheric CO2
Atmospheric CO2 average 6
Carbon (109 metric tons) 4
Despite this rapid increase in  carbon emissions, only about  half the carbon can be detected in the atmosphere. The remainder of the carbon dioxide is being dissolved in the oceans or incorporated into trees.  2
1955
1965
1975
1985
1995
2005
Year

16. Future Carbon Dioxide Levels
Increasing CO2 emissions, especially in China and developing countries
Likely to double within 150 years:
Increased coal usage
Increased natural gas usage
Decreased petroleum usage (increased cost and decreasing supply)
Future Carbon Emissions 
will probably increase, especially in China and developing countries 
This will result in a likely doubling of carbon dioxide levels within 150 years, due to 
Increased coal usage 
And increased natural gas usage, 
although petroleum usage is likely to decrease due to increased cost and decreasing supply 

17. Kyoto Protocol Adopted in 1997
Cut CO2 emissions by 5% from 1990 levels for
Symbolic only, since cuts will not significantly impact global warming
In an effort to reduce carbon emissions, the Kyoto protocol 
was adopted in 
It proposed to cut CO2 emissions by 5% from 1990 levels for period of 
However, such minor cuts would be symbolic only, since such cuts would not significantly impact global warming 

18. Past Temperatures 

19. Recorded Worldwide Temperatures
0.8
0.6
0.4
Decreasing
Flat
0.2
D Mean Temperature (°C)
0.0
 This is a graph of the change in worldwide temperatures over the last 120+ years. Although the trend is decidedly upward, there are periods when temperatures are  flat or  even slightly decreasing, suggesting that increasing temperatures may not be entirely due to increased carbon dioxide levels. 
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-0.6
1880
1900
1920
1940
1960
1980
2000
Year

20. Historic Los Angeles Temperatures
Annual Temperatures 15 16 17 18 19 20 21 22
1880
1900
1920
1940
1960
1980
2000
Year
Temperature (°C)
Summer Temperatures 18 19 20 21 22 23 24 25
1880
1900
1920
1940
1960
1980
2000
Year
Winter Temperatures 10 11 12 13 14 15 16 17
1880
1900
1920
1940
1960
1980
2000
Year
The previous graph does not tell the entire story, since temperature changes have not occurred to the same extent during different seasons. For example, in Los Angeles,  temperatures have risen pretty dramatically over the last 120+ years. However,  summer temperatures have not risen as quickly. In fact, summer temperatures  in the 1880’s were about the same as summer temperatures  in the 2000’s. In contrast,  winter temperatures have risen much more consistently and dramatically. Global warming models have predicted that warming will be greater during the winter than the summer. 

21. 2007 Temperature Changes Compared to 1951-1980-3
-2.5
-1.5 -1
-.5
-.1 .1 .5 1
1.5
2.5
3.4
This is a map of global temperature changes for the year 2005 compared to a base period of The colors in the reds and oranges represent temperature increases, whereas areas colored with blue represent temperature decreases. As can be  seen here there are few areas of temperature decreases, and nearly all of the dramatic temperature increases have occurred in the far northern latitudes. 

22. Past Temperatures Measurement
Proxy – a method that approximates a particular measurement (e.g., temperature)
Ice cores
Pollen records
Plant macrofossils
Sr/Ca isotope data
Oxygen isotopes from speleothem calcite (stalactites and stalagmites)
 Past temperatures changes beyond 120 years ago are approximated through what are called proxies. Common proxies include  ice cores,  pollen records,  plant macrofossils,  Sr/Ca isotope data, and  oxygen isotopes from stalactites and stalagmites. 

23. Temperature History of the Earth
Little ice age ( ) – 1°C cooler
Medieval warm period ( ) – 1°C warmer than today
Cool/warm cycles occur ~1,500 years
Affect mostly Northeastern U.S. and North Atlantic
Mostly due to changes in thermohaline circulation 
Dramatic shutdown of thermohaline circulation occurred 8,200 years ago as a large lake in Canada flooded the North Atlantic
Now let’s examine the temperature history of the earth based upon these proxies.  Most recently, the earth was up to 1° C cooler than today, during what has been called the “Little Ice Age”. Preceding this period was the “Medieval warm period” during which time temperatures were up to 1° C warmer than today.  These periods of modest temperature changes occur at ~1,500 year intervals,  affecting mostly Northern Europe and the North Atlantic.  These temperature changes are largely the result of changes in what is called the thermohaline circulation.  In this model, cold water in the North Atlantic sinks and flows south through deep currents.  Warm water from the south flows north, moderating the climate of Europe and Eastern North America.  A dramatic shutdown of thermohaline circulation occurred 8,200 years ago as a large lake in Canada flooded the North Atlantic, resulting in much cooler temperatures in Europe. 

24. Main Ocean Currents
In fact, ocean currents are extremely important in determining the climate of the world’s continents.  This model shows the major ocean currents, with orange representing warm surface currents and blue representing cold deep currents.  The light circles represent areas where heat is release into the atmosphere. 
Adapted from IPCC SYR Figure 4-2

25. Temperature History of the Earth
For the past 3 million years, the earth has been experiencing ~100,000 year long cycles of glaciation followed by ~10,000 year long interglacial periods
These climate periods are largely the result of cycles in the earth’s orbit – precession, obliquity, and eccentricity 
For the past 3 million years, the earth has been experiencing ~100,000 year long cycles of glaciation followed by ~10,000 year long interglacial periods 
These climate periods are largely the result of cycles in the earth’s orbit – precession, obliquity, and eccentricity 

26. Orbital Parameters: Precession
Apehelion
Perihelion
 Precession is the wobble of the earth’s tilt in relation to the seasons.  Right now, the earth is farthest to the Sun during northern hemisphere’s summer and nearest during northern hemisphere’s winter. However, in another 20,000 years, the earth will be reversed with the  earth closest to the Sun during northern hemisphere’s summer and farthest during northern hemisphere’s winter. 

27. Orbital Parameters: Obliquity
24.5°
22.5°
The second orbital parameter is obliquity or tilt. The earth’s tilt goes from a  minimum of 22.5° to a  maximum of 24.5°. The current tilt is 23.5°. 

28. Orbital Parameters: Eccentricity
Maximum: 0.061
Perihelion
Apehelion
Minimum: 0.005
Apehelion
The third orbital parameter is eccentricity, which is a measure of the elliptical nature of the earth’s orbit.  The maximum eccentricity is and  the minimum eccentricity is You should note that these drawings are not to scale.  The maximum eccentricity of the earth’s orbit drawn to scale looks like this! 
Not to scale!
To Scale!

29. Orbital Parameters & Earth’s Climate
Precession (22 ky)
Obliquity (41 ky)
Eccentricity (100 ky)
Temperature
So how do these orbital variations play out over time?  Precession cycles over a period of ~22 ky.  Obliquity cycles every 41 ky. And  eccentricity cycles every 100 ky.  The bottom curve represents the earth’s temperature over this same period of time. As can be seen, the cycles of glaciation closely match the earth’s cycles of eccentricity. 
1000
900
800
700
600
500
400
300
200
100
Age (kya)

30. Temperature History of the Earth
For the past 3 million years, the earth has been experiencing ~100,000 year long cycles of glaciation followed by ~10,000 year long interglacial periods
Last ice age began to thaw 15,000 years ago, but was interrupted by the “Younger Dryas” event 12,900 years ago
The last ice age began to thaw 15,000 years ago, but was interrupted by the “Younger Dryas” event 12,900 years ago. 

31. Younger Dryas Event -25 0.35 Younger Dryas -30 0.30 Medieval Warm
Little Ice Age
-35
0.25
Ice Age
Temperature (°C)
-40
Snow Accumulation (m/yr)
0.20
-45
0.15
 This graph shows temperatures and snow accumulation in Greenland for the last 20 ky.  The last ice age began to thaw  15 kya, but was interrupted by a  period of cooling, leading to the  Younger Dryas Event.  At 12,900 ya there was a period of rapid warming leading into our current interglacial period.  This period has been characterized by ~1,500 year periods of warming and cooling, with the  last warm period being known as the Medieval warm period and the  last cool period being known as the “Little Ice Age”. 
-50
0.10
-55
0.05 20 15 10 5
Age (kya)

32. Younger Dryas Event -8.0 -34 Younger Dryas -35 -7.5 -36 -7.0 -37 -6.5
-38
d18O (China)
-6.0
d18O (Greenland)
-39
-40
-5.5
The Younger Dryas event was not restricted to  Greenland, but can also be seen in proxy records from  China, shown here in blue. This data shows that it was a worldwide phenomenon. 
-41
-5.0
-42
-4.5
-43
-4.0
-44 16 15 14 13 12 11 10
Age (kya)

33. Temperature History of the Earth
Middle Pliocene (3.15 to 2.85 million ya)
Temperatures: 2°C higher than today.
20°C higher at high latitudes
1°C higher at the Equator
Sea levels were 100 ft higher
Causes
CO2 levels that were 100 ppm higher
Increased thermohaline circulation
During the
Middle Pliocene (from 3.15 to 2.85 million ya) 
temperatures were an average of 2°C higher than today, 
but up to 20°C higher at high latitudes, 
and only 1°C higher at the Equator. 
In addition, sea levels were 100 ft higher. 
The warmer climate of this era most likely resulted from 
carbon dioxide levels that were 100 ppm higher than today, 
and increased thermohaline circulation 

34. Temperature History of the Earth
Eocene (41 million years ago)
Opening of the Drake Passage (between South America and Antarctica).
Increased ocean current exchange
Strong global cooling
First permanent glaciation of Antarctica ~34 million years ago
Cooler temperatures were present during the 
Eocene period (about 41 million years ago) 
The opening of the Drake Passage (between South America and Antarctica) 
Led to in increased ocean current exchange 
Resulting in strong global cooling 
And the first permanent glaciation of Antarctica ~34 million years ago 

35. Temperature History of the Earth
Paleocene Thermal Maximum (55 mya)
Sea surface temperatures rose 5-8°C
Causes
Increased volcanism
Rapid release of methane from the oceans
During the 
Paleocene Thermal Maximum (about 55 mya), 
sea surface temperatures rose between 5 and 8°C. 
This warming was probably caused by 
increased volcanism 
and a rapid release of methane from the oceans 

36. Temperature History of the Earth
Mid-Cretaceous ( mya)
Much warmer
Breadfruit trees grew in Greenland
Causes
Different ocean currents (continental arrangement)
higher CO2 levels (at least 2 to 4 times higher than today, up to 1200 ppm)
During the 
Mid-Cretaceous period (about mya) 
Temperatures were much warmer than today and 
Breadfruit trees grew as far north as Greenland 
This period was much warmer due to 
different ocean currents, because of the arrangement of continents 
and higher CO2 levels, which were at least 2 to 4 times higher than today, up to 1200 ppm. 

37. Recent Temperature Changes

38. “Hockey Stick” Controversey
0.6
Direct temperature measurements
Mann et al. 1999
0.4
0.2
Temperature Change (°C)
-0.2
-0.4
In 1998 and 1999, Michael Mann et al. published a study detailing his  proxy reconstruction of global temperatures for the last 1,000 years. The graph is basically flat,  other than the rapid increase of temperatures during the 20th century. The study received wide acclaim, especially after publication by the IPCC (Intergovernmental Panel on Climate Change) and is  now referred to as the “Hockey Stick Graph”.  The curve in pink represents actual temperatures measured over the last 120+ years. 
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1200
1400
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Year

39. Is the Hockey Stick Correct?2
Mann et al. 1999
Esper et al. 2002 1
Temperature Change (°C)
 A number of studies were published after the Mann study.  In 2002 Esper et al. published a study covering the same period of time, but with much higher variations of temperature over time.  So, although the ups and downs are roughly in the same place, the magnitudes of those ups and downs are vastly different.  -1 -2
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1000
1200
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Year

40. Is the Hockey Stick Correct?
0.4
0.2
0.0
-0.2
-0.4
Temperature Change (°C)
-0.6
Mann et al. 1999
Esper et al. 2002
Moberg et al. 2005
Mann et al. 2008
 Again, the 1999 Mann study is shown in green.  Another study, by Moberg et al., using different proxy measures found higher magnitude differences in temperatures.  Here the results of Esper et al. are shown on the same scale. Several other studies have been published that fall between the extremes of these three studies.  Mann added multiple proxy data to his analysis in 2008, which showed higher variation than the 1999 study.  However, all the studies show a rapid increase in temperature in the 20th century that is unmatched by any previous temperature changes over the last millennium. 
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800
1200
1600
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Year

41. U.S. National Academy of Sciences: June 2006
0.6
“2:1 chance of being right”
“high level of confidence”
0.4
0.2
Temperature Change (°C)
-0.2
-0.4
In June, 2006, the U.S. National Academy of Sciences weighed in on the question of the Mann study.  They put a “high level of confidence” in the last 400 years of proxy results,  but only a 2:1 chance of being right for the first 600 years of data. 
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1200
1400
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Year

42. Atmospheric Temperatures
Troposphere
Stratosphere
0.8
1.5
0.6
1.0
0.4
0.5
0.2
Temperature Cgange (°C)
0.0
0.0
Satellite temperature measurements of the lower and upper atmosphere have been carried out since  Temperatures of the troposphere show gradually increasing temperatures (although not as high as would be predicted),  and decreasing temperatures in the stratosphere, which would be expected under global warming models. 
-0.2
-0.5
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-1.0
1980
1990
2000
1980
1990
2000
Year
Year

43. CO2 Concentration Vs. Temperature
370
320 31 30
CO2 (ppm) Antarctica
SST (°C) Tropical Pacific
270 29 28
Is there a correlation between carbon dioxide levels and temperatures? If we compare  carbon dioxide measurements from Antarctica with  sea surface temperatures from the tropical Pacific, we find that there is a high coincidence of carbon dioxide levels and temperatures in the past. 
220 27 26
170 25
600000
400000
200000
Time (YBP)

44. Consequences of Global Warming

45. Global Warming Primarily Impacts the Northern Hemisphere
Northern vs. Southern Latitude
Land vs. Ocean
1.0
Northern Hemisphere
Southern Hemisphere
Land
Ocean
0.8
0.6
0.4
Temperature Change (°C)
0.2
0.0
If we examine global warming from the perspective of the two hemispheres, we find that  temperatures in the northern hemisphere have increased much more than  temperatures in the southern hemisphere. In a similar fashion,  temperatures over land masses have increased much more than  temperatures over the oceans. This is because the oceans tend to moderate temperature changes. So, since two thirds of the earth’s land mass is in the northern hemisphere, we would expect global warming to have its largest impact there. 
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1920
1960
2000
1920
1960
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Year
Year

46. 2007 Temperature Changes Compared to 1951-1980
Hence we see reason for the temperature changes seen in this graph.  -3
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-.1 .1 .5 1
1.5
2.5
3.4

47. Ice Sheets Melting?
GRACE (gravity measured by satellite) found melting of Antarctica equivalent to sea level rise of 0.4 mm/year (2 in/century)
Zwally, 2005 (satellite radar altimetry)
confirmed Antarctica melting
Greenland ice melting on exterior, accumulating inland (higher precipitation)
With these temperature increases, one main question is whether the ice sheets of Antarctica and Greenland are melting.    

48. Melting Glaciers – Mt. Kilimanjaro
Mount Kilimanjaro is the poster child of the global warming movement, since most of the glacier has disappeared over the last 30 years. However experts agree that the shrinking of the Mount Kilimanjaro glacier is more the result of deforestation of the surrounding area than changes due to global warming.

49. Changes in Antarctica Ice Mass
1000
800
600
400
Ice Mass (km3)
200
These are the result of the GRACE study,  which show decreasing ice mass in Antarctica from 2002 to 
-200
-400
-600
2003
2004
2005
Year

50. Rise in Sea Levels? Present rate is 1.8 ± 0.3 mm/yr (7.4 in/century)
Accelerating at a rate of ± mm/yr2
If acceleration continues, could result in 12 in/century sea level rise
Scenarios claiming 1 meter or more rise are unrealistic
Are sea levels rising? 
The present measured rate is 1.8 mm/yr, which is equivalent to 7.4 in/century 
Another study indicates that this rate is accelerating at 13 thousandths of a mm per year per year 
If this acceleration continues, this could result in a 12 inch sea level rise in this century 
Scenarios claiming a 1 meter or more rise in sea levels are unrealistic. 

51. Global Temperature Change
Changing Sea Levels 20
Global Temperature Change 10
Relative Sea Level (cm)
Measurement of sea levels have been carried out for three European ports over the last few hundred years. The results can be seen for a  port in the Netherlands,  one in France,  and one in Poland.  When the sea level is compared to recorded temperatures over this period of time, the correlation is quite good. 
-10
Amsterdam, Netherlands
Brest, France
Swinoujscie, Poland
-20
1700
1750
1800
1850
1900
1950
2000
Adapted from IPCC SYR Figure 2-5

52. SST (°C) Tropical Pacific
Sea Levels for 450,000 Years 20 31 30
-20 29
-40
Sea Level (m) 28
SST (°C) Tropical Pacific
-60 27
-80
This graph shows  sea levels of the Red Sea over the last 450,000 years. If we overlay  sea surface temperatures, we can see a direct correlation between sea levels and temperature. In fact, some of the rise in sea levels is due to the expansion of water at higher temperatures, and not solely due to the melting of ice.  26
-100
-120 25
450
400
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150
100 50
Time (KYBP)

53. Increase in Hurricanes?
1860
1880
1900
1920
1940
1960
1980
2000
2020 5 10 15
Data Unreliable
Scaled August-October Sea-Surface Temperature
Adjusted Atlantic Storm Power Dissipation Index
SST/SPDI (meters3/sec2)
Two studies showed the total number of hurricanes has not changed
However, the intensity of hurricanes has increased (more category 4 and 5 hurricanes and cyclones)
Probably due to higher sea surface temperatures (more energy)
Difficult to know if this trend will continue
The year 2005 was marked by a number of destructive hurricanes. What this just an unusual year or a trend that has resulted from climate change? 
Two studies showed the total number of hurricanes has not changed 
However, the intensity of hurricanes has increased (more category 4 and 5 hurricanes and cyclones) 
This increase in intensity is probably due to higher sea surface temperatures, which provide more energy to the storms. 
However, it is difficult to know if this trend will continue. 

54. How Much Temperature Increase?
Some models propose up to 9°C increase this century
Two studies put the minimum at 1.5°C and maximum at 4.5°C or 6.2°C
Another study puts the minimum at 2.5°C
How much will temperatures increase in the future? 
Some models propose up to 9°C increase this century 
Two studies put the minimum at 1.5°C and maximum at 4.5°C or 6.2°C 
Another study puts the minimum at 2.5°C 

55. Wildlife Effects Polar Bears Sea turtles
Require pack ice to live
Might eventually go extinct in the wild
Sea turtles
Breed on the same islands as their birth
Could go extinct on some islands as beaches are flooded
Other species may go extinct as rainfall patterns change throughout the world
Some species of wildlife could be greatly affected by global warming 
For example, polar bears 
require pack ice in order to hunt and live. 
If all pack ice disappears, they might eventually go extinct in the wild. 
Sea turtles 
breed on the same islands as they are born on. 
They could go extinct on some islands as beaches are flooded before new beaches are produced. 
Other species may go extinct as rainfall patterns change throughout the world. 

56. Effect on Humans Fewer deaths from cold, more from heat
Decreased thermohaline circulation
Cooler temperatures in North Atlantic
CO2 fertilization effect
Precipitation changes
Droughts and famine (some areas)
Expanded arable land in Canada, Soviet Union
Global warming will affect peoples throughout the world. For example, 
Fewer deaths will result from cold weather, but more deaths will result from heat waves 
Initially, decreased thermohaline circulation will result in 
cooler temperatures in North Atlantic. 
The CO2 fertilization effect will increase crop yields by up to 30% 
Precipitation changes will result in 
droughts and famine in some areas and 
expanded arable land in Canada, Soviet Union 

57. Potential Worldwide Precipitation Changes
This map represents possible changes in worldwide precipitation as a result of global warming.  Some areas (primarily in the northern latitudes) will experience increased precipitation, whereas  other areas will experience decreased precipitation. 
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-20
-10 -5 5 10 20 50

58. Drought in Africa Lake Faguibine Lake Chad
Africa's drought troubles began well before greenhouse gases increased to any appreciable degree. The inhabitants of Northern Africa have systematically cut down trees for firewood for thousands of years. The result has been that transpiration has decreased, decreasing rainfall and expanding the Sahara Desert. Similar deforestation is now occurring over much of Africa. The result is that the deserts of North, South and East Africa are expanding, leading to drought. Coupled with global warming induced changes in precipitation, it is likely that the peoples of much of Africa will be suffering from drought and starvation in the coming decades.

59. Cost to Stabilize CO2 Concentrations
1800
1600
1400
1200
1000
Cost (Trillons U.S. Dollars)
800
600
Depending upon the scenario,  the cost to stabilize carbon dioxide concentrations will be expensive (from 200 times the U.S. annual budget) to very expensive (up to 900 times the U.S. annual budget). 
400
200
450
550
650
750
Carbon Dioxide (ppm)

60. Possible Solutions to Global Warming

61. Mitigation of Global Warming
Conservation
Reduce energy needs
Recycling
Alternate energy sources
Nuclear
Wind
Geothermal
Hydroelectric
Solar
Fusion?
Methods of mitigating global warming include 
Conservation 
Reduce energy needs, such as electrical usage, petroleum usage, reduced packaging 
Recycling, which uses less energy to produce products compared to 
Another way to reduce carbon emissions is to use alternate energy sources, such as 
Nuclear 
Wind 
Geothermal 
Hydroelectric 
Solar 
Fusion? 

62. Storage of CO2 in Geological Formations
Depleted oil and gas reservoirs
CO2 in enhanced oil and gas recovery
Deep saline formations – (a) offshore (b) onshore
CO2 in enhanced coal bed methane recovery 4 1 3b 3a 2
Another promising way to reduce global warming is to store carbon dioxide underground.  Carbon dioxide can be pumped into depleted oil and gas reservoirs.  In addition, carbon dioxide can be pumped into existing oil and gas deposits to enhance recovery. Another method is to pump carbon dioxide into deep saline formations  both offshore  and onshore.  Carbon dioxide can also be used to enhance methane recovery from coal beds. 
Adapted from IPCC SRCCS Figure TS-7

63. Conclusions Global warming is happening
Most warming is probably the result of human activities
There will be positive and negative (mostly) repercussions from global warming
The costs to mitigate global warming will be high – better spent elsewhere?
In conclusion,
Global warming is happening 
Most of the warming is probably the result of human activities 
There will be positive but mostly negative repercussions from global warming 
The costs to mitigate global warming will be high – better spent elsewhere? 