2. The Greenhouse Effect What is the greenhouse effect? Interaction between planet’s atmosphere, star’s light Results in heating of planet What causes the greenhouse effect? Surface absorbs high-energy light from Sun Surface releases lower-energy light (infrared) Infrared light absorbed, re-emitted by gases Increases gas’ energy; results in temperature increase

3. Water on Earth Factors for liquid water Distance from Sun (“Goldilocks Zone”) Greenhouse effect (requires atmosphere) Earth’s atmosphere 78% Nitrogen (N 2 ) 21% Oxygen (O 2 ) 1% trace gases Carbon dioxide (CO 2 ) Water vapor (H 2 O) And many others! Image obtained from: http://www.solarviews.com/raw/earth/bluemarblewest.jpg

4. Greenhouse Gases N 2, O 2, not good greenhouse gases Greenhouse gases efficient at absorbing infrared light Most important greenhouse gases in atmosphere: H 2 O CO 2 CH 4 (methane) Image obtained from: http://www.interiordesigninspiration.net/wp-content/uploads/2013/08/Greenhouse-Construction-116.jpg

5. Global Warming Gradual increase in global average temperature 1 ° C since 1900 Are human activities causing global warming? What other factors can affect global temperatures? Does global warming affect peoples’ lives?

6. Global Warming: Temperature Variation

7. Global Warming: What You Need To Know Video obtained from: https://www.youtube.com/watch?v=xcVwLrAavyA

9. Water on Earth Factors for liquid water Distance from Sun (“Goldilocks Zone”) Greenhouse effect (requires atmosphere) Earth’s atmosphere 78% Nitrogen (N 2 ) 21% Oxygen (O 2 ) 1% trace gases CO 2 H 2 O And many others!

10. The Greenhouse Effect What is the greenhouse effect Interaction between planet’s atmosphere, star’s light Results in heating of planet What causes the greenhouse effect? Surface absorbs high-energy light from Sun Surface releases lower-energy light (infrared) Infrared light absorbed, re-emitted by gases Increases gas’ energy; results in temperature increase

11. Water on Earth Factors for liquid water Distance from Sun (“Goldilocks Zone”) Greenhouse effect (requires atmosphere) Earth’s atmosphere 78% Nitrogen (N 2 ) 21% Oxygen (O 2 ) 1% trace gases CO 2 H 2 O And many others!