1. Environmental History What causes “natural” environmental change?

2. External Changes 1.Solar luminosity 2.“Slowing” of Earth’s rotation 3.Earth’s orbit 4.Magnetic field 5.Meteorite/comet impacts

3. Solar Luminosity

4. Earth’s Rotation & the Moon

5. Orbital Changes

6. Magnetic Field

7. Meteorite/Comet Impacts

8. Environmental History What causes “natural” environmental change? Internal Changes 1.Plate tectonics 2.“Natural disasters” 3.Atmospheric changes 4.Climate change 5.Rising & falling sea level

9. Plate Tectonics

10.  Earth’s “surface” is broken into plates  Plates move  “Geology happens” where the plates interact with one another

11. Growth of Continents

12. “Natural Disasters”

13. Atmospheric Changes

14. Climate Change

15. Sea Level Changes

16. So why are we concerned about “human” changes?

17. ImPaCT ( Ehrlich & Holdren) Human Impact (Im) = Population (P) x Consumption (C) x Technology (T)