1. Why should we be concerned about Global Warming? Why should we be concerned about Global Warming?

2. “Why should we be concerned about Global Warming?” “Why should we be concerned about Global Warming?” Many people consider that Global Warming is the greatest environmental threat of the 21st Century. However, during the 80s and early 90s scientists argued about the causes and effects of global warming. In the late 1990s scientists reached a consensus that global warming was a cause for concern. So, why should you be concerned about global warming?

3. 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?

4. 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)

5. History of Earth’s Climate Life appeared ~3.8 billion years ago Photosynthesis began 3.5-2.5 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

6. Sun Earth’s Temperature Solar Energy Solar Energy Solar Energy Solar Energy

7. Sun Earth’s Temperature Solar Energy Solar Energy Radiative Cooling Radiative Cooling

8. Sun Earth’s Temperature Solar Energy Solar Energy Radiative Cooling Radiative Cooling

9. Sun Earth’s Temperature Solar Energy Solar Energy Radiative Cooling Radiative Cooling

10. Greenhouse Effect Sun

11. Earth’s Atmospheric Gases Nitrogen (N 2 ) Oxygen (O 2 ) Water (H 2 O) Carbon Dioxide (CO 2 ) 99% Methane (CH 4 ) 1% Non- Greenhouse Gases Greenhouse Gases

12. Sun Runaway Greenhouse Effect 97% carbon dioxide 3% nitrogen Water & sulfuric acid clouds Temperature: 860°F Venus

13. Carbon Dioxide

14. 170 220 270 320 370 420 200000400000600000 Time (YBP) CO 2 (ppm) Vostok Ice CoreDome Concordia Carbon Dioxide Levels 0 Muana Loa Readings CO 2 Levels Since 1958 310 330 350 370 10203040 CO 2 (ppm) 0

15. Worldwide Carbon Emissions Carbon (10 9 metric tons) 0 1 2 3 4 5 6 7 8 175018001850190019502000 Year Liquid fuel Total Gas fuel Solid fuel

16. Annual Carbon Emissions Annual carbon emissions Atmospheric CO 2 Atmospheric CO 2 average 195519651975198519952005 0 4 6 8 2 Year Carbon (10 9 metric tons)

17. Future Carbon Dioxide Levels Increasing CO 2 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)

18. Kyoto Protocol Adopted in 1997 Cut CO 2 emissions by 5% from 1990 levels for 2008-2012 Symbolic only, since cuts will not significantly impact global warming

19. Past Temperatures

20. -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1880190019201940196019802000 Year  Mean Temperature (°C) Recorded Worldwide Temperatures Flat Decreasing

21. Winter Temperatures 10 11 12 13 14 15 16 17 1880190019201940196019802000 Year Summer Temperatures 18 19 20 21 22 23 24 25 1880190019201940196019802000 Year Annual Temperatures 15 16 17 18 19 20 21 22 1880190019201940196019802000 Year Temperature (°C) Historic Los Angeles Temperatures

22. -3-2.5-1.5-.5-.1.1.511.52.53.4 2007 Temperature Changes Compared to 1951-1980

23. 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)

24. Temperature History of the Earth Little ice age (1400-1840) – 1°C cooler Medieval warm period (800-1300) – 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

25. Main Ocean Currents Adapted from IPCC SYR Figure 4-2

26. 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

27. Orbital Parameters: Precession Perihelion Apehelion

28. Orbital Parameters: Obliquity 22.5° 24.5°

29. Orbital Parameters: Eccentricity Perihelion Apehelion Minimum: 0.005 Maximum: 0.061 Not to scale! To Scale!

30. Orbital Parameters & Earth’s Climate Age (kya) 10009008007006005004003002001000 Eccentricity (100 ky) Temperature Obliquity (41 ky) Precession (22 ky)

31. 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

32. Younger Dryas Younger Dryas Event -55 -50 -45 -40 -35 -30 -25 05101520 Age (kya) Temperature (°C) 0.05 0.10 0.15 0.20 0.25 0.30 0.35 Snow Accumulation (m/yr) Little Ice Age Ice Age Medieval Warm

33. Younger Dryas Event -44 -43 -42 -41 -40 -39 -38 -37 -36 -35 -34  18 O (Greenland) -8.0 -7.5 -7.0 -6.5 -6.0 -5.5 -5.0 -4.5 -4.0 10111213141516  18 O (China) Younger Dryas Age (kya)

34. 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  CO 2 levels that were 100 ppm higher  Increased thermohaline circulation

35. 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

36. 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

37. Temperature History of the Earth Mid-Cretaceous (120-90 mya) Much warmer Breadfruit trees grew in Greenland Causes  Different ocean currents (continental arrangement)  higher CO 2 levels (at least 2 to 4 times higher than today, up to 1200 ppm)

38. Recent Temperature Changes

39. “Hockey Stick” Controversey 100012001400160018002000 -0.8 Year -0.6 -0.4 -0.2 0 0.2 0.4 0.6 Temperature Change (°C) Direct temperature measurements Mann et al. 1999

40. Esper et al. 2002 80010001200140016001800 -2 0 1 2 Temperature Change (°C) 2000 Year Is the Hockey Stick Correct?

41. -1.2 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0400800120016002000 Year Temperature Change (°C) Mann et al. 1999 Esper et al. 2002 Moberg et al. 2005 Mann et al. 2008

42. U.S. National Academy of Sciences: June 2006 100012001400160018002000 -0.8 Year -0.6 -0.4 -0.2 0 0.2 0.4 0.6 Temperature Change (°C) “high level of confidence”“2:1 chance of being right”

43. -0.5 0.0 0.5 1.0 1.5 198019902000 Year -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8 198019902000 Year Temperature Cgange (°C) Atmospheric Temperatures TroposphereStratosphere

44. 170 220 270 320 370 0 0 200000 400000 600000 Time (YBP) CO 2 (ppm) Antarctica 25 26 27 28 29 30 31 SST (°C) Tropical Pacific CO 2 Concentration Vs. Temperature

45. Consequences of Global Warming

46. Global Warming Primarily Impacts the Northern Hemisphere -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0 192019602000 Year Temperature Change (°C) 192019602000 Year Northern vs. Southern LatitudeLand vs. Ocean Northern Hemisphere Southern Hemisphere Land Ocean

47. 2007 Temperature Changes Compared to 1951-1980 -3-2.5-1.5-.5-.1.1.511.52.53.4

48. 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)

49. Melting Glaciers – Mt. Kilimanjaro

50. 1000 800 600 400 200 0 -200 -400 -600 2003 2004 2005 Ice Mass (km 3 ) Year Changes in Antarctica Ice Mass

51. Rise in Sea Levels? Present rate is 1.8 ± 0.3 mm/yr (7.4 in/century) Accelerating at a rate of 0.013 ± 0.006 mm/yr 2 If acceleration continues, could result in 12 in/century sea level rise Scenarios claiming 1 meter or more rise are unrealistic

52. Changing Sea Levels 1700175018001850190019502000 -20 -10 0 10 20 Relative Sea Level (cm) Adapted from IPCC SYR Figure 2-5 Amsterdam, Netherlands Brest, France Swinoujscie, Poland Global Temperature Change

53. Time (KYBP) Sea Level (m) 20 0 0 -20 -40 -60 -80 -100 -120 Sea Levels for 450,000 Years 450 400 350 300 250 200 150 100 50 0 0 25 26 27 28 29 30 31 SST (°C) Tropical Pacific

54. Increase in Hurricanes? 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 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 1860 1880 1900 1920 1940 1960 1980 2000 2020 0 0 5 5 10 15 Data Unreliable Scaled August-October Sea-Surface Temperature Adjusted Atlantic Storm Power Dissipation Index Scaled August-October Sea-Surface Temperature Adjusted Atlantic Storm Power Dissipation Index SST/SPDI (meters 3 /sec 2 )

55. 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

56. Wildlife Effects Polar Bears  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 Polar Bears  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

57. Effect on Humans Fewer deaths from cold, more from heat Decreased thermohaline circulation  Cooler temperatures in North Atlantic CO 2 fertilization effect Precipitation changes  Droughts and famine (some areas)  Expanded arable land in Canada, Soviet Union

58. Potential Worldwide Precipitation Changes -50-20-10-55102050

59. Drought in Africa Lake Faguibine Lake Chad

60. Cost to Stabilize CO 2 Concentrations 450550650750 1800 1600 1400 1200 1000 800 600 400 200 0 Carbon Dioxide (ppm) Cost (Trillons U.S. Dollars)

61. Possible Solutions to Global Warming

62. Mitigation of Global Warming Conservation  Reduce energy needs  Recycling Alternate energy sources  Nuclear  Wind  Geothermal  Hydroelectric  Solar  Fusion?

63. Storage of CO 2 in Geological Formations 1.Depleted oil and gas reservoirs 2.CO 2 in enhanced oil and gas recovery 3.Deep saline formations – (a) offshore (b) onshore 4.CO 2 in enhanced coal bed methane recovery 1.Depleted oil and gas reservoirs 2.CO 2 in enhanced oil and gas recovery 3.Deep saline formations – (a) offshore (b) onshore 4.CO 2 in enhanced coal bed methane recovery Adapted from IPCC SRCCS Figure TS-7 3a 2 2 3b 1 1 4 4

64. 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?