1. Climatology and Paleoclimatology Paleoclimate Summary Climate Issues

2. Climatology and Paleoclimatology Paleoclimate Summary Climate Issues QUIZ! Last Updated: May 17, 2015 On a scale of 0 - 10: The ozone hole and global warming are related. 0 No way! 10 You Betcha! 5 Coward

3. Climatology and Paleoclimatology Paleoclimate Summary Climate Issues QUIZ! Last Updated: May 17, 2015 On a scale of 0 - 10: We are currently in a cool period of climate. 0 How quickly you forget summer. 10 COOL! 5 Who knows? I’ve got my air conditioner on!

4. Climatology and Paleoclimatology Paleoclimate Summary Climate Issues Driving Questions 1. How do we know that the composition of the atmosphere has changed in the past? 2. Ignoring greenhouse gas emissions what climate changes might we expect next? Today’s Issues: Last Updated: May 17, 2015

5. Climatology and Paleoclimatology Paleoclimate Summary Climate Issues Climate has changed quite naturally over time Today’s Issues: Last Updated: May 17, 2015

6. Climatology and Paleoclimatology Paleoclimate Summary Climate Issues Methods for establishing past temperature s Isotopic Geochemical Studies: The study of rock isotopic ratios, ice core bubbles, etc. Dendochronology: the study of tree rings Pollen Distribution: the study of plant types and prevalence Lake Varves: (like dendochronology, but with lake sediments) Coral Bed Rings Fossils: Studies of geological settings, etc. Historical documents, paintings, etc. Today’s Issues: Last Updated: May 17, 2015

7. Climatology and Paleoclimatology Paleoclimate Summary Climate Issues Paleoclimatology “Heavy” oxygen happens… Isotropic Geochemica l Studies

8. Climatology and Paleoclimatology Paleoclimate Summary Climate Issues Paleoclimatology Dating Through Oxygen Isotope Ratios

9. Climatology and Paleoclimatology Paleoclimate Summary Climate Issues Paleoclimatology Dating Through Oxygen Isotope Ratios

10. Climatology and Paleoclimatology Paleoclimate Summary Climate Issues Paleoclimatology

11. Climatology and Paleoclimatology Paleoclimate Summary Climate Issues Vostok Record  18 O is well correlated with temperature!

12. Climatology and Paleoclimatology Paleoclimate Summary Climate Issues Sea Sediments 18 O in sea sediments is used to suggest temperature Seawater 18 O variations over time can be linked to the growth and decay of ice sheets. During the last ice age sea level was ~130m lower than today reflecting about 3% of the ocean's volume. Consequently the 18 O of the ocean was ~1.2 permille heavier (higher) than it is today. Measuring the 18 O in foraminifera allows to reconstruct past variations in the size of the ice sheets over millions of years.

13. Climatology and Paleoclimatology Paleoclimate Summary Climate Issues

14. Climatology and Paleoclimatology Paleoclimate Summary Climate Issues Milankovitch theory of climate change Eccentricity : 400 ka and 100 ka

15. Climatology and Paleoclimatology Paleoclimate Summary Climate Issues Obliquity: 41 ka Milankovitch theory of climate change

16. Climatology and Paleoclimatology Paleoclimate Summary Climate Issues Axial Precession : 23 ka Milankovitch theory of climate change

17. Climatology and Paleoclimatology Paleoclimate Summary Climate Issues Paleoclimatology

18. Climatology and Paleoclimatology Paleoclimate Summary Climate Issues Glacial Milankovitch theory of climate change Ice Growth Configuration:Low eccentricity Low Tilt Large Earth-Sun Distance in Summer Net Effect:Less seasonal contrast

19. Climatology and Paleoclimatology Paleoclimate Summary Climate Issues Inter- Glacial Milankovitch theory of climate change Ice Growth Configuration:High eccentricity High Tilt Small Earth-Sun Distance in Summer Net Effect:More seasonal contrast

20. Climatology and Paleoclimatology Paleoclimate Summary Climate Issues Milankovitch theory of climate change Take-away: Variations in our orbit begin to explain the variation in temperature over scales of >10,000 years.

21. Climatology and Paleoclimatology Paleoclimate Summary Climate Issues Changes in CO 2 (0 - 500,000,000 YBP) Paleoclimatology Geochemically inferred. NOW

22. Climatology and Paleoclimatology Paleoclimate Summary Climate Issues Changes in CO 2 (0 - 25,000,000 YBP) Paleoclimatology NOW

23. Climatology and Paleoclimatology Paleoclimate Summary Climate Issues Changes in CO 2 (0 - 450,000 YBP) Paleoclimatology Vostok NOW

24. Climatology and Paleoclimatology Paleoclimate Summary Climate Issues Changes in CO 2 (0 - 450,000 YBP) Paleoclimatology NOW Vostok

25. Climatology and Paleoclimatology Paleoclimate Summary Climate Issues Lessons from Vostok

26. Climatology and Paleoclimatology Paleoclimate Summary Climate Issues Lessons from Vostok 1.Past changes in climate have often been triggered by changes in orbital characteristics. 2.These initial changes are then amplified by changes in CO 2 and CH 4 concentrations. 3.The changes in greenhouse gas concentrations then exaggerate the temperature changes over the earth.

27. Climatology and Paleoclimatology Paleoclimate Summary Climate Issues Changes in CO 2 (0 - 12,500 YBP) Paleoclimatology NOW

28. Climatology and Paleoclimatology Paleoclimate Summary Climate Issues RAPID Changes in Climate Happen Climate

29. Climatology and Paleoclimatology Paleoclimate Summary Climate Issues RADIATION TEMPERATURE ICE VOLUME

30. Climatology and Paleoclimatology Paleoclimate Summary Climate Issues Changes in CO 2 (0 - 12,500 YBP) Paleoclimatology NOW

31. Climatology and Paleoclimatology Paleoclimate Summary Climate Issues Changes in CO 2 (0 - 800 YBP) Paleoclimatology NOW

32. Climatology and Paleoclimatology Paleoclimate Summary Climate Issues Paleoclimatology NOW Changes in CO 2 (0 - 50 YBP)

33. Climatology and Paleoclimatology Paleoclimate Summary Climate Issues Summary Driving Questions 1. How do we know that the composition of the atmosphere has changed in the past? Keywords: Isotope Ratios Ice Cores

34. Climatology and Paleoclimatology Paleoclimate Summary Climate Issues Summary Driving Questions 2 Ignoring greenhouse gas emissions what climate changes might we expect next? Keywords: Milankovitch Theory oEccentricity oPrecession oObliquity

35. Climatology and Paleoclimatology Paleoclimate Summary Climate Issues Abrupt extinction due to climate change Paleoclimatology Abrupt climate change (circa 2200 BC)forced the abandonment of rain-fed settlements in agricultural plains of lower Mesopotamia.

36. Climatology and Paleoclimatology Paleoclimate Summary Climate Issues Paleoclimatology Period of drought between ~800 to 1000 A.D. probably contributed to collapse of Mayan civilization.

37. Climatology and Paleoclimatology Paleoclimate Summary Climate Issues Paleoclimatology