1. The Greenhouse Effect (8.6)

2. The Greenhouse Effect  How does the climate system trap energy to keep Earth warm?  Gases in the atmosphere absorbed the IR radiation emmitted by the earth and radiate it in all directions  Half gets sent back to earth to warm it up even more  The energy trapping process is called the greenhouse effect!

4. Greenhouse gases MAJOR  Carbon Dioxide  0.0385% of atmosphere (not a lot!)  Causes ¼ of natural greenhouse effect  Natural sources: volcanoes, burning organic matter, cell respiration  Water Vapour  2/3 of Earth’s natural greenhouse effect  Amount varies from very little to 4% of atmosphere MINOR  Methane  Much less in atmosphere but 23x more effective than CO2  Natural sources: plant decomposition  Ozone  Acts as greenhouse gas in troposphere  Nitrous Oxide  Very little in atmosphere but 300x more effective than CO2  Natural Source: reactions of bacteria in soil

5. Videos!  https://www.youtube.com/watch?v=Hi3E Res0h84 https://www.youtube.com/watch?v=Hi3E Res0h84  http://ed.ted.com/lessons/climate- change-earth-s-giant-game-of-tetris-joss- fong#review http://ed.ted.com/lessons/climate- change-earth-s-giant-game-of-tetris-joss- fong#review

6. Energy Transfer within the climate system (8.8)

7. Energy Transfer in the Atmosphere  Convection current:  Air near the equator warms up, rises and spreads and then the cooler air drops and the cycle repeats  This causes winds that are predictable  Prevailing winds help push warm air and water to the poles  Another factor in determining climate zones!

10. Energy Transfer in the Oceans  Thermohaline circulation:  At the poles, surface water freezes and leaves saltier colder water which is more dense and sinks to the bottom  This allows warmer surface water from the equator to flow to the poles  Acts as a conveyer belt carrying water from the equator to the poles  Ocean currents can also be caused by winds  Have a strong effect on climates of land nearby  Warm water  warm moist air  warms land  rain  Cold water  cool dry air  cools land  desert

12.  https://www.youtube.com/watch?v=ajQ3 hm5JidU https://www.youtube.com/watch?v=ajQ3 hm5JidU

13. HOMEWORK!  Read pg. 338-347  Questions:  Pg. 342 #1-3, 6  Pg. 347 #1, 3, 6-7