1. Climate Change and Earth
Mommy, what were glaciers like?

2. Goals The Earth’s unique atmosphere?
How does what we know about natural climate change relate to what humans can do?

3. Why is Earth so Different?
Why do we have oceans of water?
Why do we have so little carbon dioxide?
Why do we have so much O2 and N2?

4. Compared to Venus Temperature just right. Water vapor could rain.
Liquid oceans didn’t completely evaporate.
CO2 could dissolve in oceans.
60x CO2 dissolved in oceans as atmosphere.
170,000x CO2 in carbonate rocks as atmosphere.

5. Goldilocks Planet Delicate balance: Earth is just right.
No oceans without greenhouse gasses.
Without oceans too many greenhouse gasses.
Without oceans no life.
Without life, no ozone.
No ozone, no life.
How does Earth maintain this balance?

6. Carbon Cycle
Tectonics are crucial!

7. Nature’s Thermostat Carbon Cycle has negative feedback.
Increasing temperatures lead to feedback that decreases temperatures, etc.
Positive and negative feedbacks have nothing to do with desirability of outcome.

8. Too Cool
Less Rain
Less CO2 dissolves in oceans.
More CO2 builds up in atmosphere
Increased greenhouse
Heats Up.

9. Too Warm
More Rain
More CO2 dissolves in oceans.
Less CO2 builds up in atmosphere
Decreased greenhouse
Cool Down.

10. Ice Ages and Cycles

11. Cycles

13. Human Input Affecting CO2 cycle.
Moving C from ground to air at increased rate.
No increase in rate of C from air to ground.

14. Mars Today

15. Positive Feedback Fossil Fuels – Increase CO2 to atmosphere.
Deforestation – decrease CO2 from atmosphere
Increase CO2 – Increase greenhouse effect
Increase temp – Melting glaciers, ice sheets, polar caps
Less ice – lower planetary albedo
Lower albedo – Earth absorbs more light
More absorption – Increasing surface temperatures.