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Human Impact on the Environment: Current Crises for Human Survival: Problems to be Solved Within the Next Generation Practical observation of ONE example of human ... – PowerPoint PPT presentation

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Title: Human%20Impact%20on%20the%20Environment:


1
Human Impact on the Environment
  • Current Crises for Human SurvivalProblems to be
    Solved Within the Next Generation
  • Practical observation of ONE example of human
    influence on the environment in the local area
    (e.g. the impact of alien species on
    biodiversity). Written report on the chosen
    example.
  • Look at the interrelatedness and interdependence
    of the human impacts and the environment.

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Research Human impact on the environment
Discuss what you understand these terms to mean
4
The atmosphere and climate change
  • carbon dioxide emissions
  • - concept of carbon footprint and the need to
  • reduce the carbon footprint
  • - deforestation
  • - greenhouse effect and global warming
  • desertification, drought and floods
  • - methane emissions
  • - ozone depletion.

5
http//www.vanderbilt.edu/sustainvu/2009/03/so-wha
t-is-a-carbon-footprint-and-why-is-vanderbilt-calc
ulating-one/
6
Non-natural sources of CO2
  • Burning fossil fuels for electricity
  • For transportation
  • South Africa is 13th in the world and 1st in
    Africa for CO2 emissions.

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Carbon footprint the amount of carbon dioxide or
other carbon compounds emitted into the
atmosphere by the activities of an individual,
company, country.
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Brainstorm what you can do to reduce your carbon
footprint
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Enhanced greenhouse effect (leads to global
warming)
http//www.epa.gov/climatechange/kids/basics/index
.html
11
Methane emissions
  • SOURCES
  • Anaerobic respiration in the intestines of
    herbivores
  • Decomposition of organic waste
  • Treatment of waste water (sewerage)
  • Agricultural activities (e.g. rice paddies)
  • Mining
  • Making and using of fossil fuels and biofuels.

12
DEFORESTATION
Forests take out CO2 from the air. But we are
cutting down forests for fuel, wood, paper,
grazing space, roads, mining and agriculture.
This results in less CO2 being removed from the
atmosphere
13
We have to stop cutting down trees!  This is
getting really serious!
14
  • Desertification the productive potential of arid
    and semi-arid lands falls and topsoil is lost or
    degraded.
  • Desertification results mainly from a combination
    of natural climate changes causing prolonged
    drought and unsustainable human activities,
    including overgrazing and deforestation.
  • Desertification may lead to the formation of a
    desert or the encroachment of an existing desert
    onto formerly arable land.

Overgrazing on marginal lands (top) can extend
desert zones (lower)
15
Effects of Climate Change
FLOODING
16
Effects of Climate Change
DROUGHT
17
Effects of Climate Change
http//www.epa.gov/climatechange/kids/
Research what individuals, schools, communities
and businesses can do to reduce climate change
18
EFFECTS OF CLIMATE CHANGE
See pg 336
19
OZONE DEPLETION
  • The ozone layer protects Earth from harmful UV
    radiation. However, it is getting thinner due to
    CFCs.
  • CFCs are released by refrigerators and aerosol
    cans.
  • EFFECTS
  • Causes some trees to die ? more greenhouse effect
  • Increased skin cancer
  • Can affect human immune systems.

20
HOW TO REDUCE CLIMATE CHANGE PG 339
21
Most household cleaning can be done with a
half-and-half mixture of vinegar and water, or
liquid soap and baking soda.
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If it has a thermostat it uses a large amount of
electricity.
How can your family/school reduce its electricity
consumption?
24
Ways to reduce climate change see pg 339.
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WaterAvailability
  • Construction of dams
  • - Destruction of wetlands
  • - Poor farming practices
  • - Droughts and floods
  • - Exotic plantations and depletion of water table
  • - Boreholes and effects on aquifers
  • - Wastage
  • - Cost of water

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South Africa gets about half the amount of
rainfall that other countries receive. Mostly
arid
33
1. CONSTRUCTION OF DAMS
  • Functions of dams
  • Stores water for human needs (residential,
    industrial and agricultural).
  • Controls flood waters
  • Can be used to generate hydro-power

34
  • NEGATIVES
  • Affects flow downstream, impacting on humans and
    the natural communities.

35
2. DESTRUCTION OF WETLANDS
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What is a wetland?
  • Wetlands are areas where terrestrial and aquatic
    ecosystems come together.
  • In a wetland, the water table is at or near the
    surface of the ground. The land is either
    temporarily or permanently covered with shallow
    water.

http//wetlands.sanbi.org/
37
  • Wetlands are a source of water
  • Wetlands purify water .

38
DESTRUCTION OF WETLANDS
  • Destroyed by
  • Draining the water
  • Filling with soil
  • Removing plants
  • (urbanisation)

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3. POOR FARMING PRACTICES
  • Water is needed for irrigation.
  • Much water however is lost through poor
    practices. E.g. Open ditch irrigation and
    ploughing along the slope.

41
4. DROUGHTS AND FLOODS
  • Due to climate change, some areas will become
    drier and others wetter.

Floods and Droughts
42
5. Exotic plantations and the depletion of the
water table.
  • Exotic plantations can be beneficial financially.
  • Exotic plants have deeper roots and use more
    water than indigenous plants and thus deplete the
    water table

Exotic plantations
43
6. Boreholes and effects on aquifers
  • Aquifer permeable rock, saturated with water.
  • Boreholes remove water from aquifers and only
    precipitation and rivers can recharge these
    systems

44
7. Wastage
  • Poor practices
  • Leaks

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8. Cost
  • 6 kilolitres given free per household.

48
ACT 3.6.9 pg 354 (exclude no2 )
49
Water Quality
  • - Water for domestic use, industry, agriculture
    and mining pollution, diseases, eutrophication
    and algal bloom.
  • - The effect of mining on quality of water
  • - Thermal pollution The need for water
    purification and recycling
  • - Alien plants, e.g., Eichornia

50
Uses of water
  • DOMESTIC washing, cooking, cleaning, gardening,
    etc)
  • INDUSTRIAL USES parts of ingredients, to cool
    down machinery.
  • AGRICULTURAL Drinking water for livestock and
    watering (irrigation)
  • After being used water is polluted.

51
WATER POLLUTION
  • Domestic pollutants detergents and pathogenic
    bacteria from sewage.
  • Industrial pollutants heavy metals, paints
    solvents, oil, heat
  • Agricultural pollutants pesticides, herbicides
    and fertilisers.

52
EUT ROPHICATION
  • Excess fertilisers ? water system ? nutrients (N
    and P) ? rapid growth of algae (algal blooms)
    ?Block sunlight ? plants die ? decomposition ?
    oxygen is used up ? animals die.

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EFFECT OF MINING
  • Releases acidic water with a high temperature
    (thermal pollution) which contains heavy metals
    (poisonous).

55
THERMAL POLLUTION
  • Increased temperature of water.
  • Some benefit, but others negatively affected,
    because warm water has less O2. Warm waters more
    likely to get algal blooms.

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EFFECT OF ALIEN PLANTS
  • Some alien species grow out of control
    (invasive). No natural predators/parasites ?
    outcompete indigenous species.

Water hyacinth (Eichhornia crassipes)can form a
continuous layer blocking light. The impact is
similar to that of algal blooms. They also
prevent recreational activities. It cost millions
of rands to clear them from the water.
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