1. CLIMATE

2. Weather & Climate
Weather = Meteorological conditions in a given place on a given day (e.g. the actual temperature at a specific place and time)
Climate = Long-term averages, patterns, or trends in the weather (e.g the expected range of temperatures that are likely at a specific place and time)

4. 1000 nm

7. What can change global energy balance?
Change in solar output
Change in earth’s orbit (eccentricity, axial tilt, precession)
Change in amount/distribution of continents
Change in surface characteristics (albedo)
Change in clouds
Change in atmospheric chemistry

8. History of Earth’s Climate
Early Earth ( BYA)
Sun cooler
Atmosphere N2, CO2, CH4, NH3
Smaller continents
Primitive marine life (bacteria, archaea)

9. Great Oxygenation Event

10. Glaciation
not all due to photosynthesis

11. Snowball Earth

12. Carboniferous Glaciation
Meganeuropteris
Arthropleura

13. Permian Hothouse
250 MYA massive eruptions of flood basalts in Siberia (Siberian Traps) added so much CO2 to the atmosphere that climate warmed rapidly, possibly releasing CH4 from methane hydrates. What followed was the greatest extinction in earth history.

14. Cretaceous Climate

16. PETM (Paleocene-Eocene Thermal Maximum)
Global Warming 4-8 C
Marine carbonate dissolution
Total duration > 100,000 years

17. Methane hydrates

18. Cenozoic Climatic Deterioration

20. Australia separates from Antarctica

21. Circum-antarctic current
Psychrospheric circulation
Global temperatures drop
Ice caps,glaciers grow
Sea level drops (100 m)
Grasslands replace forests
Mammals get larger
Faunas/floras and environments look “modern”

22. Thermohaline circulation intensified
More herbaceous plants
More pollinating insects
More passerine birds
More rodents
More snakes
Larger faster grazing horses
More grasses (esp C4)
Larger nonarboreal primates

23. Pleistocene 2.6 MYA – 11,700 years ago

24. 18O/16O can be used to detect changes in ice volume and global temperature.
16O preferentially evaporates from oceans (less preference with higher temp)
Leaving increasing 18O in seawater and increasing 16O in glaciers

28. Glaciation acts as species pump

29. Causes of Glaciation Solar radiation Greenhouse gases
Continental configuration
Ocean currents
Albedo
Orbital characteristics

30. Milankovitch Cycles

32. Late Pleistocene Extinction (may still be going on)
10,000-20,000 years ago
Most mammals > 100 lbs
Mammoths
Mastodons
Horses (obviously not all)
Bison (were 3 in N Am and 1 in Europe)
Casteroides (Giant Beaver)
Bears
Sabertoothed Cats
Camels
Ground Sloths
Why?
Hunting ? (humans are world-wide and tech. advanced)
Climate ?
Disease ?