Transcript 6-4 Charting a Course for the Future

Human Impact
Charting a Course
for the Future
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Charting A Course
Key Concept:
As We Enter The 21st Century, Many
Biologists Are Concerned About The
Biological Effects Of Global Change
To:
1. Resources
2. Air
3. Water
4. Biodiversity
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Oxygen Gas
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Ozone Molecule
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Ozone Depletion
• Ozone layer
–20/50 km above earth (12 – 31 miles)
–Oxygen = O2
–Ozone = O3
• Ozone at ground level is a pollutant
• In the upper atmosphere it is VERY
important
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Ozone Layer
• Absorbs Ultraviolet Radiation (UV)
• UV Radiation Can Cause:
– Sunburn
– Cancer
– Eye Damage
– Cataracts
– Decreased Resistance To Disease
– Destruction of Plants & phytoplankton
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Ozone
The Universal Sunscreen
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Ozone
Hole
South
Pole
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Ozone Depletion
•
•
•
•
Discovered in 1970’s over Antarctica
Hole is growing larger
Now occurring over the Arctic
1995
– grew large enough to expose U.S.
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Ozone Hole Caused By
CFC’s
Chlorofluorocarbons
CFC’s act as a catalyst
CFC’s have a long half-life
2O3 + CFC’s
3O2
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Where Do CFC’s Originate?
• CFC’s found in
–aerosol cans
–coolants used in
• refrigerators
• freezers
• automobile air conditioning
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Montreal Protocol
1987
46 Nations
Agreed to end use of CFC’s
by 2000
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Change In Atmospheric Chlorine
14
Parts per Billion
12
10
8
6
4
2
0
1950
1970
Historical
1990
2000
2010
NoRestrictions
2030
2050
Montreal
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2070
2090
All Nations
Global Warming
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Global Warming
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Global Warming
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Global Warming
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Climate Change
• Any Climate Change will have profound
effects on the Biosphere.
• Over past 120 years average global
temperature has increased 0.5 degrees
Celsius (0.9 degrees F)
• Rise between 1980-2000 fastest in over
100 years.
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Climate Change
• Ice caps are
melting
• Arctic Sea Ice
may be gone in
50 years
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Why is it happening?
• CO2
Methane (Greenhouse Gases)
• Burning Fossil Fuels, Forests
• Project Increase of 1 – 2 degrees
Celsius by 2050
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Global Warming Effects
• Polar Ice Melt
• Rising Sea Levels
• Increase in number & severity of
storms
• North American droughts
• Shifts in plant & animal species
distribution
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Ways to Help the Biosphere
• Decrease energy consumption
– Insulate Homes
– Energy Efficient Appliances
– High Mileage Cars
– High Efficiency Energy Production
• Alternate Fuel Sources
– Fuel Cells
– Wind
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