Transcript Global Warming The Greenhouse Effect

Elgqvist 2014
 In



a greenhouse and a car:
Sunlight enters through a window
Warms surfaces (light energy changed to heat)
Glass, which was transparent to light, does not
let the heat back out
 http://epa.gov/climatestudents/basics/toda
y/greenhouse-effect.html
 http://science.howstuffworks.com/environm
ental/203-what-is-the-greenhouse-effectvideo.htm
 http://www.youtube.com/watch?v=dPtg4atr5M
 Sunlight
1.
2.
3.
hits earth
Some is reflected back to space
Some is absorbed by earth’s surface
Some is radiated back to atmosphere
 “greenhouse
gases” in earth’s atmosphere absorb
heat radiation, holding some of the heat in
 Without greenhouse gases, the earth would be
super hot during the day, and super cold at night
 Water
vapor
 Carbon dioxide, CO2
 Methane (20-25 x more powerful at heat
trapping than CO2)
 Nitrous Oxide
 Argon
 Chlorofluorocarbons (CFC’s)

http://epa.gov/climatestudents/basics/today/greenhouse
-gases.html

Water vapor


Water cycle – evaporation
Carbon Dioxide
Forest fires
 Cellular respiration – ALL living things do this
 Decomposition


Methane

Decomposition


Argon


In intestines, this results in “natural gas” from the rear end :/
Naturally occurring element in atmosphere
Chlorofluorocarbons (CFC’s)
Man-made substances
 Used for propellants (spray cans, etc.)
 now banned
 Destroy ozone


Burning fossil fuels and other combustion of organic
compounds


Deforestation


Produces CO2 and Nitrous oxide and “bad” ozone at ground level
Takes away the trees that would normally be absorbing the carbon
dioxide
Raising livestock
Produces extra methane, and
 uses many resources that burn fossil fuels (tractors, etc. to grow
10x more feed than would be needed if we ate the plants
directly)


Hydraulic fracturing


If not properly fitted, wells can leak methane directly into air
Landfills

Methane produced from rotting garbage – should be collected and
burned off
http://www.epa.gov/climatechange/science/causes.html
1.
2.
3.
4.
Earth warms
Permafrost melts
Methane is released from melting permafrost
Go back to 1.
“Drunken trees”: ground
getting soggy from melting

Earth warms
Ocean warms
Dissolved CO2 is released
1.
2.
3.
1.
4.
(warm water holds less dissolved gas than cold
water – think warm, flat Coke)
Go back to 1.
Continents are shown in black.
http://www.scientificamerican.com/article.cfm?id=graphic-science-map-shows-vast-regions-ocean-
1.
2.
3.
4.
5.
Earth warms
Ice sheets melt
Surface darker, less reflective (lower
albedo)
Surface absorbs more heat
Go back to 1.
 Shifting
climate zones
 Rising sea levels – 2 ways


added melt water
thermal expansion (warm water takes more
volume than cold water)
 Extreme

Due to acceleration of water cycle and the fact
that warm air holds more water vapor than cold
 Ocean

weather patterns
acidification
From extra CO2
 Extinction

of species
Reefs destroyed, habitats destroyed, ecosystems
disrupted
 Earth
is 4.6 billion years old
 There have been multiple periods of global
warming and cooling throughout earth’s history
(WAY before man’s arrival on the scene)
 Evidence
of this can be found in the rock record
and ice cores.


Slight changes in earth’s orbit (eccentricity)
and tilt (obliquity)
 These
are on tens of thousands to hundreds of
thousands year cycles

http://www.ces.fau.edu/nasa/module-3/temperaturetrend-changes/causes-glaciation.php
 The
current warming
trend is more like 150 yrs
http://earth.usc.edu/classes/geol150/stott/variability/orbitalchanges.html

Volcanic activity
 Produces
ash
clouds that can
shade earth
enough for global
cooling
 Also can produce
sulfurs and carbon
dioxide that can
add greenhouse
gases, resulting in
global warming
Erupted June
1991
 Sulfur dioxide
goes up to
stratosphere,
reacts and
forms sulfuric
acid aerosols
which reflect
sun’s ray’s
 cooled earth
measurably for
two years

http://earthobservatory.nasa.gov/IOTD/view.php?id=1510
http://www.wunderground.com/climate/volcanoes.asp
http://www.wunderground.com/climate/volcanoes.asp

Solar activity


Cycles have been shown NOT to align with current pattern of warming
Solar maximums happen about every 11 years
http://data.giss.nasa.gov/gistemp/2010summer/

Photosynthesis

As plant life evolved, the atmospheric content changed to
contain more oxygen and less CO2, allowing progressive
cooling (this took millions and millions of years)
http://www.visuallanguagelab.com/cast/index.html
 Data
shows that in past cooling and warming
cycles, the changes in temperature preceded
changes in CO2 content
 The
opposite is now the case