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Human Impact on the Environment :

Human Impact on the Environment :

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Human Impact on the Environment :

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  1. 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 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.

  2. Research: Human impact on the environment Discuss what you understand these terms to mean

  3. 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. 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.

  6. Carbon footprint: the amount of carbon dioxide or other carbon compounds emitted into the atmosphere by the activities of an individual, company, country.

  7. Brainstorm what you can do to reduce your carbon footprint

  8. Enhanced greenhouse effect (leads to global warming)

  9. 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.

  10. 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

  11. We have to stop cutting down trees!*  *This is getting really serious!*

  12. Desertificationthe 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)

  13. Effects of Climate Change FLOODING

  14. Effects of Climate Change DROUGHT

  15. Effects of Climate Change Research what individuals, schools, communities and businesses can do to reduce climate change


  17. OZONE DEPLETION • The ozone layer protects Earth from harmful UV radiation. However, it is getting thinner due to CFC’s. • CFC’s are released by refrigerators and aerosol cans. • EFFECTS: • Causes some trees to die → more greenhouse effect • Increased skin cancer • Can affect human immune systems.


  19. Most household cleaning can be done with a half-and-half mixture of vinegar and water, or liquid soap and baking soda.

  20. If it has a thermostat it uses a large amount of electricity. How can your family/school reduce its electricity consumption?

  21. Ways to reduce climate change see pg 339.

  22. Water:Availability: • 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

  23. South Africa gets about half the amount of rainfall that other countries receive. Mostly arid

  24. 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

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


  27. 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.

  28. Wetlands are a source of water • Wetlands purify water .

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

  30. 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.

  31. 4. DROUGHTS AND FLOODS Due to climate change, some areas will become drier and others wetter. Floods and Droughts

  32. 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

  33. 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

  34. 7. Wastage • Poor practices • Leaks

  35. 8. Cost • 6 kilolitres given free per household.

  36. ACT 3.6.9 pg 354 (exclude no2 )

  37. 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

  38. 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.