How do humans impact their environment?

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How do humans impact their environment?

• SOL WG.2b

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Water Diversion/Management

• Humans have invented several techniques for
  managing water supplies such as building
  reservoirs and canals for irrigating crops and
  ensuring a constant supply of water.

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Examples

• The Aral Sea
• Colorado River
• Aswan High Dam

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The Aral Sea

• The Aral Sea is located in Central Asia between
  Kazakhstan and Uzbekistan. Since the 1960s it
  has been shrinking due to over irrigation.

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The Aral Sea

• The shrinking of the Aral Sea has caused
• The collapse of the local fishing industry
• Increase in respiratory illnesses due to wind
  stirring up dust of exposed seabed
• Extinction of plants and animals

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The Aral Sea
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The Aral Sea
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The Colorado River

• The Colorado River starts in Colorado and empties
  into the Gulf of California. On every stretch of
  the river farmers take water to irrigate crops.
  People have also built several dams on the river,
  the most famous is the Hoover Dam.

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The Aswan High Dam

• The Aswan High Dam was built on the Nile River in
  1960 - 1970.

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Aswan High Dam (Benefits)

• The dam provides around 15 of Egypts
  electricity.
• The dam has stopped the Nile River from flooding
  every year.
• The dam created Lake Nasser, which provides water
  for irrigation and local use.

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Aswan High Dam (Negatives)

1. Around 90,000 people had to move.
2. The dam blocks nutrient rich silt from being
   deposited on farmland and farmers have to use
   artificial fertilizers.
3. Poor irrigation practices have led to an increase
   of salt in surrounding farmland.
4. Fish stocks in the Mediterranean have depleted
   because the dam blocks nutrients from entering
   the sea.

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Changing Landscapes

• Agricultural Terracing
• Polders
• Deforestation
• Desertification

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Agricultural Terracing

• People practice agricultural terracing in
  mountainous areas in order to make flat land to
  farm on.

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Agricultural Terraces in Peru
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Cultivation of Rice in Terraces in China
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Polders

• A polder is an area of reclaimed land from the
  sea.
• Polders are found in countries with low
  elevations next to the sea such as Belgium and
  the Netherlands.

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Netherlands without polders
Netherlands with polders
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Deforestation

• Deforestation is when humans cut down trees
  faster than they can grow back.

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Deforestation

• A few causes of deforestation are
• Forest land is cleared for farming or human
  settlement.
• Forests are cut down and the timber is sold.
• Slash and burn farming in tropical areas.

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Desertification

• Desertification is an expansion of arid
  conditions into a non-arid environment.

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Desertification

• Desertification occurs near deserts. The region
  directly south of the Sahara Desert in Africa is
  called the Sahel. This area has suffered from
  rapid desertification due to over grazing,
  droughts, and poor water management practices.

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Map of Western Africa showing Sahel
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Pollution

• Humans cause air, water, soil, and nuclear
  pollution that harm the environment.

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Air Pollution

• Air pollution is mostly caused by the burning of
  fossil fuels oil, coal, and natural gas. Areas
  with many coal burning power plants, factories,
  and cars can experience acid rain.

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Acid Rain

• A few areas that have acid rain are the Northeast
  United States and Canada, the Black Forest region
  in Germany, and China. Acid rain can kill
  vegetation and fish in streams and lakes over a
  period of time.

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Water Pollution

• Water pollution is caused by
• Runoff that contains pesticides and fertilizers
• Waste from heavy industry that contains metals
  and chemicals
• Raw sewage
• Oil spills and waste from ships

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Water Pollution

• A few areas that have severe water pollution are
• Most of the rivers in Europe
• The Ganges River in India

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Nuclear Pollution

• An example of nuclear pollution is when the
  Chernobyl nuclear power plant in the former
  Soviet Union exploded causing radioactive waste
  to contaminate the air and soil

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Chernobyl

• In 1986, one of the reactors at the nuclear power
  plant exploded causing a cloud of radioactive
  material that drifted and fell over parts of
  Russia and Europe. Over 300,000 people were
  forced to evacuate the nearby city of Pripyat and
  today the city is abandoned.

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