1. Example: Snowball Earth Hoffman and Schragg, Sci. Am. 2000 Several putative episodes between 750 Myr and 580 Myr ago. Evidence controversial, but puzzling (e.g., glaciers at sea level at the equator Freeze-fry cycles (global mean temperature -40C to 40C !)

2. 50 Myr ago, Eocene warm period Crocodiles on Ellesmere Island (80N) How do you get crocodiles (cold-blooded) to survive through the polar night on Ellesmere Island? Or palm trees in Wyoming (interior of continents)?.

3. The last 70 Million years (Zachos et al.,Science 2001)

4. The Ice Ages (Proxy for global ice volume)   O in ocean sediment Time (Myr) Long term cooling and cyclic ice ages over the last 4 Myr

5. The Ice Ages

6. A wobbly planet (Milankovitch) Time (kyr)

7. The ice ages CLIMAP reconstruction February July Reconstruction of land and sea ice 21,000 years ago

8. Different wildlife!

9. Ice sheet margin (northern Greenland)

10. mid Holocene 5000 to 6000 yrs ago - Hippos in the Sahara Lamb: Climate, history, and the modern world

11. The little ice age ~1600 to ~1850 Extensive advance of glaciers in Europe Long, severe winters Was it global? Abraham Hondius, 1684 A Frost Fair on the Thames at Temple Stairs (1684)

12. oCoC Warm phaseCool phase

13. Mantua et al., 1997 Example of PDO impacts

14. El-Nino Southern Oscillation Nino 3 index of Pacific sea surface temperatures

15. Climate impacts of ENSO are global

16. North American temperatures

17. Sea surface temperatures