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Greenhouse Effect
Mechanisms Impacting Greenhouse
Evidence for Climate Change
I. Greenhouse Vocabulary
1. Greenhouse Effect – an atmosphere’s ability to trap and retain infrared radiation or heat energy.
2. Solar Radiation – radiation from the Sun the enters Earth’s atmosphere, which will be reflected or absorbed.
3. Infrared Radiation – heat energy in the form of radiation emitted and absorbed by Earth’s surface and greenhouse gases.
4. Greenhouse gases – gases in the atmosphere that absorb and emit infrared radiation. H2O, CO2, CH4, N2O
https://www.youtube.com/watch?v=ZzCA60WnoMk
http://www.sumanasinc.com/webcontent/animations/content/greenhouse.html
1. Solar radiation from Sun enters atmospherea. Reflection: (clouds, ice, water, land)b. Absorption: Land, water, ice
2. Earth’s surface emits infrared radiation (heat)a. Greenhouse gases trap infrared radiation b. CO2, H20, CH4, N2O
III. Milankovitch Cycles
IV. Milankovitch Cycles
Interglacial PeriodDecreased Solar
Radiation
Glacial Period (Ice Age)
Increased Solar Radiation
Orbit100,000 y. cycle
Circular Oval (Stretched)
Tilt41,000 y. cycle
More tilt: 24.4˚ Less tilt: 21.8˚
Wobble(-/+ tilt)
Ice age is strengthened when north pole is tilted away from sun at Earth’s greatest distance from sun.
1. Increased Solar Reflection
a. Volcanic ash, impact ash, glaciers
b. Plate tectonics /ocean currents/ice
caps
2. Cooling ocean: absorbing CO2
1. More greenhouse gases
a. Changes in cycles that recycle gases
b. Burning of fossil fuels/forests
c. Warming ocean: off gassing (CO2)
d. Volcanic gases
2. Less reflection
Evidence for Climate Change
PAST PRESENTNorth America Ice AgeGlacial material & landforms, lakes, sea levels, extinctions
• Rising surface temperatures• Rising ocean temps• Rising sea levels
Eocene ThermalMaximum
Sea levels, ocean core samples,extinctions
• Changing migrations• Species moving northward
Snowball EarthDrop-stones in marine mud at equator
• Retreating Glaciers (melting)• North pole ice cap shrinking
Feedback Loops – Speed up glacier growth or glacier melt.