Human Activities and the Earths

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Human Activities and the Earths Valuable Water
and Air Resources
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Objectives
Ozone Depletion Global Warming and Global Climate
Change Acid Rain Biological Magnification Human
Impacts on Water, Air, Fisheries What we can do
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Ozone Depletion

• Ozone layer (20-50km up) protects
• the Earth from UV radiation
• Gases (CFCs) used in aerosols break
• down ozone causing the holes over the
• Arctic and Antarctica
• Montreal Protocol stopped production
• of CFCs on January 1, 1996
• Holes are not growing but will not recover until
  . . . . . . . 2065!

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Excess UV radiation

• Skin cancer

• Cataracts
• Immune System Problems
• Other unknown effects on plant/animal life

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Global Warming

• Caused by gases (mostly CO2) that trap heat
• Burning of fossil fuels, cutting/burning of
  forests
• releases CO2 faster than Carbon cycle can
• remove it
• Temperatures have risen 0.6oC. since industrial
• age
• Since 1980, average temp risen 0.3OC.

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Global Warming Global Climate Change

• Melting of permafrost, increasing release of
• greenhouse gases
• Melting of poles
• Rising sea level
• Flooding, Drought
• Loss of habitat, species extinction
• Loss of coral reef ecosystems (fisheries, tourist
  
• revenue, natural storm barriers)
• All the above have economic impacts

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Acid Rain

• Burning of fossil fuels release nitrogen and
  sulfur
• gases
• Combined with H2O vapor nitric and sulfuric
  acids
• Fall as acid rain
• Plants damaged
• Soil chemistry altered, potentially hazardous
• compounds released and flow into water system
• (mercury)

BIOMAGNIFICATION
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Eastern U.S average pH of 3.6, with some
values as low as pH 2.6 Los Angeles pH of fog
has been measured at 2.0
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Biomagnification
Pesticides and heavy metals work their way into
rivers or lakes and move up the food chain
becoming more concentrated at each level
Silent Spring by Rachel Carson
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FOR EXAMPLE If in one day a small fish eats
1,000 plankton and a larger fish eats 1,000
small fish, the human who catches the larger
fish is ingesting all the toxins that were in a
1,000,000 plankton! (1,000 x 1,000
1,000,000) Add that up over a lifetime and
youre in trouble!
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Clean Water

• Renewable but not unlimited!
• same water is recycled (the water cycle!)
• BUT if contaminated during that cycle, may not be
• reusable
• Two issues Pollution and loss of water
  filtration!

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• Some water pollutant sources
• Sewage
• Runoff agricultural fertilizers, factory farms
• Factory outfall

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Some Effects of Water Pollution

• Contaminated drinking water
• Contaminated food animals (biological
  magnification
• of toxins from the environment over their life
  spans)
• Unbalanced river and lake ecosystems that can no
• longer support full biological diversity
• Deforestation from acid rain
• Loss of natural beauty

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• For water use to be sustainable we need to
  protect the natural
• systems of the water cycle.
• Preserve wetland areas water filtration
• Think before you pave it less filtration
• Think before you cut it less transpiration

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Fisheries
Overfishing - harvesting fish faster than they
reproduce

• An example of tragedy of the
• commons
• Everyone uses the resource but no one
• maintains it
• If properly managed, can be a renewable
• resource

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Air

• Air Quality Issues (caused by burning of
• fossil fuels)
• Smog
• Particulates - microscopic particles of ash and
  dust
• Acid Rain
• Their Effects
• Human health
• Deforestation

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Things we can do
Dont litter Turn off lights, all electronic
equipment Recycle - dont fill up our
landfills Conservative or little use of
fertilizers Walk or bike when possible Drive more
fuel efficient vehicles Support wetlands
preservation Develop sustainable energy sources
Wind, solar, fuel cells Think before you pave
it Use sustainable building practices - green
space and gravel, porous paving Design
pedestrian friendly cities