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Exploring the Long-Term Carbon Cycle: Earth's Climate Dynamics

Delve into the complex interplay of factors shaping Earth's climate over millions of years, from plankton to tectonics. Understand how carbon influences climate at various time scales, including geologic cycles and Milankovitch orbital dynamics. Explore climate oscillations like El Niño and La Niña, and learn about the role of carbon sinks and sources in regulating atmospheric CO2 levels. Discover the connections between plants, animals, oceans, and atmospheric composition in the context of long-term climate change.

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Exploring the Long-Term Carbon Cycle: Earth's Climate Dynamics

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

  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. ClimateChange 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. ClimateChange 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. 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. South America

  7. 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. South America

  8. The Ice Record: Milankovitch

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

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

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

  12. The Ice Record: Milankovitch

  13. The Ice Record: Milankovitch Brook, 2008 Nature

  14. Carbon THE greenhouse gas

  15. The Ice Record: Milankovitch Brook, 2008 Nature

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

  17. Respiration: CH2O + O2 → CO2 + H2O + energy Photosynthesis: CO2 + H2O + light energy → CH2O + O2

  18. Icehouse Earth

  19. Sea Ice

  20. Continental Ice at the poles

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

  22. Courtesy K. Johnson

  23. Courtesy K. Johnson Fossil Lotus

  24. Living Lotus Courtesy K. Johnson

  25. Lowland rainforest, Panama

  26. Lomonosov Ridge

  27. Azolla (floating fern)

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

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

  30. Long-term Carbon Cycle: rocks Two generalized reactions… Photosynthesis/Respiration CO2 + H20 ↔ CH2O + O2 Weathering/Precipitation CO2 + CaSiO3↔ CaCO3 + SiO2

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

  32. A Carbon Thermostat • Fluxes in and out of the major reservoirs are relatively constant leading to an equilibrium in atmospheric CO2—there are negligible changes in fluxes during the Pleistocene.

  33. A Carbon Thermostat • Fluxes in and out of the major reservoirs are relatively constant leading to an equilibrium in atmospheric CO2—there are negligible changes in fluxes during the Pleistocene. • In geologic time, negative feedbacks serve to regulate the equilibrium. • High CO2, more warming, more plant growth, less CO2, less warming…

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

  35. No sources:Snowball Earth ~650 Ma

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

  37. Photosynthesis (sink): CO2 + H2O + light energy → CH2O + O2

  38. Swamp Forests of the Paleozoic

  39. Photosynthesis (sink): CO2 + H2O + light energy → CH2O + O2

  40. Weathering (sink): CO2 + CaSiO3 → CaCO3 + SiO2

  41. Precipitation (sink): CO2 + CaSiO3 → CaCO3 + SiO2

  42. Precipitation (sink): CO2 + CaSiO3 → CaCO3 + SiO2

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

  44. Georespiration (oxidation, source): CH2O + O2 → CO2 + H2O

  45. Georespiration (thermal decomposition): CH2O + O2 → CO2 + H2O

  46. Georespiration (thermal decomposition): CH2O + O2 → CO2 + H2O

  47. Georespiration (mantle source): CH2O + O2 → CO2 + H2O

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

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