1. Ian M. Miller Curator of Paleontology DMNS WIPS March Meeting, 2008 Plankton, and Plants, and Tectonics! Oh My! The role of the long- term carbon cycle in Earth’s climate.

2. Earth’s Climate The average of weather and the combination of… Solar Energy (distance from the Sun, intensity) Atmosphere (composition & currents) Oceans (composition, currents, & geology) Ice (extent on land and sea) Continents (location, elevation, & geology) Plants & Animals (on land & in the seas)

3. Climate Change At four (or five) time scales… Modern time: Anthropocene (last ~200 yrs—industrialization) Holocene (last ~10,000 yrs—human civilization) Deep Time: Pleistocene (last ~1.8 million yrs—icehouse) Previous 4.5 by (almost always a greenhouse) Phanerozoic (542 Ma to ~10 Ka)

4. Climate Change At three scales of climatic cycles… Geologic: Long-term carbon cycle (millions of yrs) Milankovitch: Earth’s orbital dynamics (400,000, 100,000, 40,000, and 20,000 Ka) Sub-Milankovitch: (amplify longer cycles) Short-term carbon cycle (~100’s to 1,000’s yrs) Solar/Sunspot cycles (~10’s to ~1000’s yrs) Climatic oscillations (2-7 yrs: El Nino La Nina)

5. Climate Oscillations:

6. South America Climate Oscillations: During “Normal Years” or La Nina Warm water in the western Pacific causes low pressure and high rainfall; pressure system drives tradewinds from east to west; tradewinds drive warm water to the west; causing cold water to rise off South America and flow west.

7. South America Climate Oscillations: During “El Nino” Warm water shift to the eastern Pacific causes drought in western Pacific; low pressure over the warm eastern Pacific causes heavy rains and inhibits upwelling along the coast of South America.

9. The Ice Record: Milankovitch

10. Orbital Eccentricity (~100,000 yr cycle)

11. Orbital Tilt (~41,000 yr cycle)

12. Orbital Precession (~23,000 yr cycle)

13. The Ice Record: Milankovitch

14. Brook, 2008 Nature The Ice Record: Milankovitch

15. Carbon THE greenhouse gas

16. Brook, 2008 Nature The Ice Record: Milankovitch

17. Short-term carbon cycle: ~10’s to 1000’s of years

18. Photosynthesis: CO 2 + H 2 O + light energy → CH 2 O + O 2 Respiration: CH 2 O + O 2 → CO 2 + H 2 O + energy

19. Icehouse Earth

20. Sea Ice

21. Continental Ice at the poles

23. Green River Fm: Greenhouse World Courtesy K. Johnson

25. Fossil Lotus Courtesy K. Johnson

26. Living Lotus Courtesy K. Johnson

27. Lowland rainforest, Panama

28. Lomonosov Ridge

29. Azolla (floating fern)

30. The Arctic Sea 50 million years ago Courtesy K. Johnson

31. Royer et al., 2003 Geologic cycles: Climate through the Phanero- zoic— carbon is the culprit

32. Photosynthesis/Respiration CO 2 + H 2 0 ↔ CH 2 O + O 2 Weathering/Precipitation CO 2 + CaSiO 3 ↔ CaCO 3 + SiO 2 Long-term Carbon Cycle: rocks Two generalized reactions…

33. Berner, 2001 Long-term carbon cycle: rocks

34. A Carbon Thermostat Fluxes in and out of the major reservoirs are relatively constant leading to an equilibrium in atmospheric CO 2 —there are negligible changes in fluxes during the Pleistocene.

35. A Carbon Thermostat Fluxes in and out of the major reservoirs are relatively constant leading to an equilibrium in atmospheric CO 2 —there are negligible changes in fluxes during the Pleistocene. In geologic time, negative feedbacks serve to regulate the equilibrium. –High CO 2, more warming, more plant growth, less CO 2, less warming…

36. No sinks: Runaway Greenhouse Effect 97% carbon dioxide 3% nitrogen Water & sulfuric acid clouds Temperature: >800°F – more than twice as hot as Mercury Venus

37. No sources: Snowball Earth ~650 Ma

38. Berner, 2001 Long-term carbon cycle: sinks

39. Photosynthesis (sink): CO 2 + H 2 O + light energy → CH 2 O + O 2

40. Swamp Forests of the Paleozoic

41. Photosynthesis (sink): CO 2 + H 2 O + light energy → CH 2 O + O 2

42. Weathering (sink): CO 2 + CaSiO 3 → CaCO 3 + SiO 2

43. Precipitation (sink): CO 2 + CaSiO 3 → CaCO 3 + SiO 2

44. Precipitation (sink): CO 2 + CaSiO 3 → CaCO 3 + SiO 2

45. Berner, 2001 Long-term carbon cycle: sources

46. Georespiration (oxidation, source): CH 2 O + O 2 → CO 2 + H 2 O

47. Georespiration (thermal decomposition): CH 2 O + O 2 → CO 2 + H 2 O

48. Georespiration (thermal decomposition): CH 2 O + O 2 → CO 2 + H 2 O

49. Georespiration (mantle source): CH 2 O + O 2 → CO 2 + H 2 O

50. Berner, 2001 Long-term carbon cycle: sources and sinks

51. How do long-term carbon flux changes alter the climate? The ice age and the oxygen maximum during the Late Carboniferous. Draw down of CO 2 leading up to the Pleistocene minimum.

52. Royer et al., 2003 Climate and Carbon through the Phanero- zoic.

53. Paleozoic Swamp Forests

55. Berner, 2003 CO 2 and O 2 through the Phanerozoic

56. Extant Dragonfly Permian Dragonfly

57. Royer et al., 2003 Climate and Carbon through the Phanero- zoic.

58. Subduction (source) then Weathering (sink)

59. Subduction then Uplift Cenozoic Deep Sea Climate Record Time, Ma

60. Brook, 2008 Nature The Ice Record

61. IPCC 2001 Temperature Curve

64. Georespiration (thermal decomposition): CH 2 O + O 2 → CO 2 + H 2 O

65. Berner, 2001 >100 times faster than volcanoes

66. 1946 – 1950 svs.gsfc.nasa.gov

67. 1956 - 1960 Temperature svs.gsfc.nasa.gov

68. 1966 - 1970 Temperature svs.gsfc.nasa.gov

69. 1976 - 1980 Temperature svs.gsfc.nasa.gov

70. 1986 - 1990 Temperature svs.gsfc.nasa.gov

71. 1996 - 2000 Temperature svs.gsfc.nasa.gov

72. 2002 - 2006 Temperature svs.gsfc.nasa.gov

73. Minimum Sea Ice 1979 September, 1979

74. Minimum Sea Ice 2005 September, 2005

75. September, 2007

77. The Long-term carbon cycle and Earths climate: Carbon cycles: Long-term carbon cycle (millions of yrs) Driver of long-term climate changes Responsible for Icehouses/Greenhouses Short-term carbon cycle (~100’s to 1,000’s yrs) May exacerbate short-lived climate events e.g. Milankovitch cycles Doesn’t play a role in long-term climate Long-term carbon cycle and today: Burning fossil fuels is like setting off volcanoes >100 times faster than present eruptions rates Running a global experiment, which in not analogous to glacial-interglacials.