Paleoclimate & Climate Change

1. Paleoclimate & Climate Change

2. The Geologic Time Scale

3. Low Resolution past 600 million

4. Vostok Data Past ½ million years

5. Younger Dryas Event = Big Freeze

6. The Younger Dryas Event • In the transition from the last glacier ice age which ended 16,000 years ago to our present day, there was a short period of intense cold. • This event occurred 11,000 years ago and is known as the Younger Dryas event. • The event lasted 1000 years and temperatures dropped 7 degrees Celsius!

7. A Dramatic Temp Decline

8. Younger Dryas Event • The Younger Dryas caused the extinction of many large mammals across N. America including Saber Toothed Cats, Mammoths, and Mastodons. • One possible explanation is that warming temperatures shut down the Atlantic Conveyor creating a dramatic climate event lowering global temperatures.

9. The Atlantic Conveyor

10. Recent Events

11. The Maunder Minimum

12. 1650 – 1720 Maunder Minimum

13. The Future • We are currently in an interglacial period. Past data would suggest that we should be heading into a cooling period however….

14. The Keeling Curve

15. Future CO2 Projections

16. Future Temperature Projections

17. Sea Level Projections

18. Gases Contributing to the Greenhouse Effect

19. Carbon Dioxide • The atmospheric lifetime of CO2 is estimated to be between 30 to 95 years. • An increase in CO2 causes an increase in temperature resulting in an increase in water vapor . It is this water vapor that contributes to most of the warming. • Methane is 72 times stronger than CO2 at absorbing heat however it is present in smaller concentrations and has a shorter life in the atmosphere

20. Future Climate Maps for US

21. Global Climate Precip. Forecast

22. Final Summary • Climate change means different “things” for different regions of the world. • Higher latitudes will experience greater temperature changes. • Computer models forecast drier conditions for much of the western and central United States.