Transcript Global Warming

By: AF
Outline
What is Global Warming?
Causes
How does it effect us?
Slow down Global warming
Conclusion
What is Global Warming?
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Heating of the Earth
 Natural and Human Influences
Causes
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Natural
 Natural cycles
 Milankovitch Cycle
 Greenhouse effect
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Humans
 Enhanced greenhouse effect
Natural Cycles
Caused by Milankovitch Cycles
Data has been recorded from over past 1
million years
 One cycle is 100,000 years
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 Two parts 80-90% in one, 10-20% in the other
○ “Ice Age” is 80-90,000 years
○ “Warming Period” is 10-20,000 years
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Current warming is part of the natural cycle
If humans had not had the industrial
revolution, we would be in the cooling
period
Milankovitch Cycles
Orbit of the Earth
 Causes ice ages and warm periods
 Ice ages occur every 100,000 years
 3 general factors determine the period
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 Eccentricity  changes in the orbit around
the sun
 Obliquity  tilt of the Earth’s axis
 Precession  wobble of the Earth’s axis
Milankovitch Cycles Cont.
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Two ways the Earth can “sit”
 Perihelion  tilt and wobble make the northern
hemisphere closer to the sun and causes
warming
 Aphelion  tilt and wobble make the northern
hemisphere farther away from the sun and
causes cooling
Eccentricity Cycle
 Longest cycle
 100,000 years long
 During the cycle, spend less time close to the sun
Milankovitch Cycles Cont.
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Obliquity Cycle
 Axis stays about 23 ½ degrees, varies 22-24 ½
 Increased obliquity causes hotter summers and cooler
winters
 Only take a few thousand years for all ice to melt
 Decreased obliquity causes cooler summers
Precession Cycle
 Wobble is driven by tidal forces which is influenced by the
moon
 Causes different types of seasons
○ Hemisphere closest to sun has warm summers and cool
winters
○ Hemisphere away from sun has warm winters and cool
summers
Greenhouse Effect
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Natural Greenhouse Effect
 Garden Greenhouse
○ Sun passes as light, energy is absorbed,
then converted into heat, this warms the
greenhouse and the glass traps the heat
31% incoming radiation reflects back to space
20% absorbed by the atmosphere
Rest is absorbed into oceans and land
Earth would be 33C colder making the
average temperature -18C instead of 15C
Greenhouse Effect Cont.
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Human Enhanced Greenhouse Effect
 Burning of fossil fuels
 CO2, methane, nitrous oxide
 From 1990, emissions increased +20% since
industrialization
 More gases are being produced than can be naturally dealt
with
 World increase by 1.9% annually between 2001-2025
 Developing countries increase 2.7% annually
○ Expected to pass first world use by 2018
Greenland Glaciers

85% of Greenland is covered by a massive
ice sheet
 Area of 1,736,000 km2, thickness of 1,500
meters, volume of 2,600,000 km3
 If it was to all melt, it would raise sea levels
by 6.4 meters

Dr. William Krabill used an airborne laser
to survey the altitude of the ice sheet in
1993-1994 and again in 1998-1999
 51 m3 was lost in between the two tests

Greenland appeared to melting!
Effects
Six Degrees Warmer
Slow Down Global Warming
Conclusion
Cannot prevent Global Warming
 Do our part to keep Global Warming as
natural as it can be
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Video Links
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http://www.youtube.com/watch?v=ROZJmX73FF4
http://www.youtube.com/watch?v=oJAbATJCugs
http://www.youtube.com/watch?NR=1&feature=fvwp&v=P-0_gDXqYeQ
http://www.youtube.com/watch?v=6rdLu7wiZOE&feature=fvwp&NR=1
http://www.youtube.com/watch?NR=1&feature=fvwp&v=skFrR3g4BRQ
http://www.youtube.com/watch?v=7nRf2RTqANg&feature=endscreen&NR
=1
http://www.youtube.com/watch?NR=1&feature=fvwp&v=O8qmaAMK4cM
http://www.youtube.com/user/NationalGeographic?feature=watch#p/sear
ch/28/mX3pHD7NH58
http://www.youtube.com/user/NationalGeographic?feature=watch#p/sear
ch/17/7lgZIR-OM48
http://www.youtube.com/watch?v=7lgZIR-OM48&lr=1&feature=watch
If you want to watch these videos, you must copy and paste the link.
Picture Citations
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http://live-the-solution.com/mindmaps/
http://byclive.blogspot.ca/2011/12/global-warming-to-savemother-earth-or.html
http://geap.wordpress.com/
http://green4u.wordpress.com/2012/04/18/finally-23-ofamerican-believe-global-warming/
http://climate.nasa.gov/kids/bigQuestions/greenhouseEffec
t/
http://www.enchantedlearning.com/subjects/astronomy/pl
anets/earth/Greenhouse.shtml
http://www.eia.gov/oiaf/1605/ggccebro/chapter1.html
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Not in order of appearance
Bibliographies
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Global Warming Natural Cycle. (n.d.). In OSS. Retrieved May 13, 2012, from
http://ossfoundation.us/projects/environment/global-warming/natural-cycle
Milankovitch Cycles. (n.d.). In OSS. Retrieved May 13, 2012, from
http://ossfoundation.us/projects/environment/global-warming/milankovitch-cycles
Earth's Fidgeting Climate. (n.d.). In NASA Science | Science News. Retrieved May 13,
2012, from http://science.nasa.gov/science-news/science-at-nasa/2000/ast20oct_1/
Greenhouse Gases. (n.d.). In EIA. Retrieved May 13, 2012, from
http://www.eia.gov/oiaf/1605/ggccebro/chapter1.html
Causes of Global Warming. (n.d.). In National Geographic. Retrieved May 13, 2012,
from http://environment.nationalgeographic.com/environment/global-warming/gwcauses
The Greeenhouse Effect. (n.d.). In Canada's Action on Climate Change. Retrieved May
13, 2012, from http://www.climatechange.gc.ca/default.asp?lang=En&n=1A0305D5-1
Climate change 101. (n.d.). In Canada's Action on Climate Change. Retrieved May 13,
2012, from http://www.climatechange.gc.ca/default.asp?lang=En&n=65CD73F4-1