Transcript Human Impact - Jackson County School District

Human Impact
How do humans impact their
environment?
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Human Impact can take several
forms
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Resource Use
Land abuse
Pollution
Loss of Biodiversity
Ozone Depletion
Greenhouse Effect
Global Warming
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Resource Use
• Whether a resource is “renewable" or
“nonrenewable" is about how long
nature takes to renew it.
• Renewable – can be renewed by nature,
includes energy sources that do not
consume fuel
• Renewable resources are NOT unlimited,
they can be abused
• Plants, animals
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Resource Use cont.
• Nonrenewable Resources –
• cannot be replenished by nature within our
lifetimes - are limited in supply
• fossil fuels, metals, other minerals
• Sustainable Use – using natural
resources at a rate that does not
deplete them
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Land Abuse
1. Soil Erosion
2. Desertification – farming and drought
turn dry grasslands into desert
3. Deforestation
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Pollution
Acid Rain burning of fossil
fuels release N2
& S which
combine with
water vapor to
form nitric and
sulfuric acid
Acid Rain
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Pollution – Biological Magnification
• Biological Magnification – concentration of
harmful substances increase in organisms as
chemical travel in the food web
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Loss of Biodiversity
• Biodiversity is the variety of living things.
• CAUSES of Loss:
• Endangered species – species that is
highly vulnerable to extinction
• Habitat loss – physical reduction in
suitable places to live
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Ozone Depletion
• layer of ozone (O3) is normally present in
Earth’s upper atmosphere
• prevents much of UV light emitted by sun
from reaching Earth’s surface
• Chlorofluorocarbons (CFCs) – in polar
atmosphere, CFCs act as catalyst that
enable UV light to break apart ozone
materials
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• What does the
Ozone Layer do?
– Ozone absorbs 99% of
the harmful ultraviolet
(UV) radiation.
•Without the Ozone Layer
Most of the harmful UV
radiation will penetrate the
atmosphere.
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This can cause skin cancer and eye problems but DOES NOT cause Global Warming!
Greenhouse Effect
• heat is retained by the layer of gases (CO2,
CH4, etc) forming the atmosphere. This is a
Natural Process!
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Global Warming
• Increase in average temperature of biosphere
• over past 120 years, global temp. has risen .5o C
• CAUSES – human activities have caused global
warming by adding CO2 and other greenhouse
gases to the atmosphere
• RESULT – atmospheric greenhouse gases
retain more heat and average temp rises. Can
cause sea level to rise and disrupt weather
patterns
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