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 need water to live and grow food. 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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Vocabulary

• Reservoir
• Irrigation
• Canal

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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. It is
  now 20 of its original size. The Soviets used
  the diverted water to irrigate cotton fields.

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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 is an excellent example of how
  humans can impact the environment through
  irrigation. The 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)

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

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Changing Landscapes

• Humans change the landscape of the earth in order
  to farm or raise animals.

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Examples

• 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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Think!

• Look at a map and try to think of some countries
  or areas where people may practice agricultural
  terracing.

A. The Andes Mountains in South America
B. The Himalaya Mountains in Asia
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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.
• Windmills were used to pump the water out of
  polders, but they have been replaced by diesel
  pumps.
• Movie http//static.nai.nl/polders/qt/640-480_h264
  .mov

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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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Slash and Burn Farming

• Slash and burn farming is a farming method used
  in tropical areas such as Brazil, Africa, and
  Southeast Asia. Farmers cut down the forest and
  burn the trees in order to fertilize the soil.
  After a few years the land becomes infertile and
  farmers must repeat the process.

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Deforestation

• Much of the world has been deforested including
  Europe and many parts of the United States.
  Areas that are becoming rapidly deforested right
  now are mainly rainforests such as the Amazon
  Rainforest in Brazil.

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Desertification

• Desertification is an expansion of arid
  conditions into a non-arid environment.
  Basically, desertification is when a desert gets
  bigger due to natural and human causes.

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Desertification

• The fringes of deserts are very fragile
  environments. If there is a long period of no
  rain such as a drought this area may turn into a
  desert. People can also cause desertification by
  cutting down trees near deserts or herding
  animals such as cattle, sheep, and goats.

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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

• Radioactive waste from nuclear power plants must
  be stored in very safe areas otherwise it can
  contaminate the water and soil
• Another 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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The Lost City

• Go here to see a lot of interesting photos of the
  city of Pripyat, a city near the power plant,
  which is abandoned to this day.
• http//englishrussia.com/?p293