Intro. to the Greenhouse Effect

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Intro. to the Greenhouse Effect

• Climate and Climate Change

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Intro. to Greenhouse EffectOutline

• Atmospheric Gases Greenhouse or Not?
• How gases can store heat energy
• Step-by-Step of the Greenhouse Effect
• How energy enters Earths systems
• How energy is absorbed and retained
• Impact on Earths Climate
• Prehistoric data
• Modern data

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Atmospheric GasesNon-Greenhouse
These gases are simple, either one atom or
two. They store energy through translating or
(sometimes) rotating.
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Atmospheric GasesGreenhouse
These gases are complex, at least three atoms
bonded together. They store energy through
translating, rotating, or complex vibrations.
For extreme physics details, CLICK HERE
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Greenhouse Effect StepsOverview
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Greenhouse Effect Steps1. Suns Energy Enters

• Most of the atmosphere is transparent to
  visible light
• Why you can see through it most of the time
• Most incoming solar radiation is visible kind
  (see graph later)

By Handyhuy (Own work) CC-BY-SA-3.0
(http//creativecommons.org/licenses/by-sa/3.0),
via Wikimedia Commons
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Greenhouse Effect Steps2. Ground Absorbs Energy

• You cant see through the Earths surface ?
• Ground and other surface features absorb visible
  light and heat up
• E.g., dark objects absorb more light and heat up
  more easily

http//blogs.kxan.com/2011/06/17/will-it-be-hottes
t-summer-ever/
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Greenhouse Effect Steps3. Ground Radiates IR
Energy

• Infrared radiation (IR) is released from warm
  bodies
• E.g., the hot ground releases it in all
  directions
• Night vision goggles pick up IR, by the way

By Brocken Inaglory (Own work) Public domain,
via Wikimedia Commons
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Greenhouse Effect Steps4. GHGs Absorb IR Energy

• Greenhouse gases (GHGs) have the complex motions
  that match the IR energy
• IR traveling from the surface hits gases
• GHGs begin vibrating (i.e., heating up, storing
  the energy)
• Heated GHGs also release IR!

By Nick84 CC-BY-SA-3.0 (http//creativecommons.or
g/licenses/by-sa/3.0), via Wikimedia Commons
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Greenhouse Effect StepsRevisited
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Impact on Earths ClimatePrehistoric Data
By Vostok-ice-core-petit.png NOAA derivative
work Autopilot (Vostok-ice-core-petit.png)
CC-BY-SA-3.0 (http//creativecommons.org/licenses
/by-sa/3.0/) or GFDL (http//www.gnu.org/copyleft/
fdl.html), via Wikimedia Commons
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Impact on Earths ClimateModern Data (Slide 1)
By US Govt (NOAA (http//www.esrl.noaa.gov/gmd/agg
i/)) Public domain, via Wikimedia Commons
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Impact on Earths ClimateModern Data (Slide 2)

• Global mean land-ocean temperature change from
  18802013, relative to the 19511980 mean. The
  black line is the annual mean and the red line is
  the 5-year running mean. The green bars show
  uncertainty estimates.

By NASA Goddard Institute for Space Studies
(http//data.giss.nasa.gov/gistemp/graphs/)
Public domain, via Wikimedia Commons
Wikipedia contributors. "Global warming."
Wikipedia, The Free Encyclopedia. Wikipedia, The
Free Encyclopedia, 12 Oct. 2014. Web. 14 Oct.
2014.
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Check yourself

• Is heat trapped on the way in or the way out?
• Given what you know about Mars and/or Venus, how
  do you think the greenhouse effect impacts their
  climates?
• How effective a greenhouse gas do you think the
  following molecule is?

By Walkerma (Own work) CC0, via Wikimedia
Commons