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.