Intro. to the Greenhouse Effect
Climate and Climate Change
Intro. to Greenhouse Effect:
Outline
• Atmospheric Gases: “Greenhouse” or Not?
– How gases can store heat energy
• Step-by-Step of the Greenhouse Effect
– How energy enters Earth’s systems
– How energy is absorbed and retained
• Impact on Earth’s Climate
– Prehistoric data
– Modern data
Atmospheric Gases:
Non-“Greenhouse”
These gases are simple, either one atom or two.
They store energy through translating or (sometimes) rotating.
Atmospheric Gases:
“Greenhouse”
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
Greenhouse Effect Steps:
Overview
Greenhouse Effect Steps:
1. Sun’s 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
Greenhouse Effect Steps:
2. Ground Absorbs Energy
• You can’t see through
the Earth’s 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-hottest-summer-ever/
Greenhouse Effect Steps:
3. 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
Greenhouse Effect Steps:
4. 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.org/licenses/by-sa/3.0)], via Wikimedia
Commons
Greenhouse Effect Steps:
Revisited
Impact on Earth’s Climate:
Prehistoric Data
By Vostok-ice-core-petit.png: NOAA derivative work: Autopilot (Vostok-ice-core-petit.png) [CCBY-SA-3.0 (http://creativecommons.org/licenses/by-sa/3.0/) or GFDL
(http://www.gnu.org/copyleft/fdl.html)], via Wikimedia Commons
Impact on Earth’s Climate:
Modern Data (Slide 1)
By US Govt (NOAA (http://www.esrl.noaa.gov/gmd/aggi/)) [Public domain], via Wikimedia Commons
Impact on Earth’s Climate:
Modern Data (Slide 2)
• “Global mean land-ocean
temperature change from
1880–2013, relative to the
1951–1980 mean. The black
line is the annual mean and
the red line is the 5-year
running mean. The green
bars show uncertainty
estimates.”
Wikipedia contributors. "Global warming." Wikipedia, The Free Encyclopedia. Wikipedia,
The Free Encyclopedia, 12 Oct. 2014. Web. 14 Oct. 2014.
By NASA Goddard Institute for Space Studies (http://data.giss.nasa.gov/gistemp/graphs/) [Public
domain], via Wikimedia Commons
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