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Impact Of Human Activities


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Impact Of Human Activities

  1. 1. Impact of human activities and Sustainable development In Amazonia
  2. 2. <ul><li>June 2005 </li></ul><ul><li>Describe traditional shifting cultivation in Amazonia </li></ul><ul><li>(6 marks) </li></ul><ul><li>June 2002 </li></ul><ul><li>Describe the traditional farming system in Amazonia known as ‘shifting cultivation’ </li></ul><ul><li>(5 marks) </li></ul><ul><li>Suggest 2 reasons why this type of farming does not cause lasting damage to the environment </li></ul><ul><li>(2 marks) </li></ul><ul><li>Shifting cultivation in Amazonia is being replaced by other types of farming. List two of the other types of farming </li></ul><ul><li>(2 marks) </li></ul>
  3. 3. Shifting cultivation <ul><li>A small clearing is made in the forest by cutting down trees which are then burnt and the ash is used as fertiliser. </li></ul><ul><li>Beans, yams, manioc and banana trees are grown by the indigenous tribes </li></ul><ul><li>After 3-4 years the clearing becomes infertile as there are no leaves falling to devay and put nutrients back into the soil. </li></ul><ul><li>Indians move on and create new clearing </li></ul>
  4. 4. <ul><li>The area slowly becomes covered in a shrub-like vegetation that grows very quickly </li></ul><ul><li>Trees cannot grow due to lack of soil fertility </li></ul><ul><li>Shifting cultivation only supports a small number of people at subsistence level and does not contribute to economy of Brazil </li></ul><ul><li>This is more sustainable than modern farming methods but it still causes considerable areas of forest to be cleared each year </li></ul>
  5. 5. Modern farming (ref pg 148) <ul><li>Cattle ranching in Mato Grosso </li></ul><ul><li>To try and make money for the country the government encouraged large companies to move in and land was often given free. </li></ul><ul><li>The World Bank lent money to the cattle ranchers to help them set up beef processing plants, and beef and leather were produced and exported to the USA </li></ul><ul><li>Large TNCs produce beef which is sold mainly to fast food chains in MEDCs. </li></ul><ul><li>To produce grazing land areas of forest were cut down and burnt. </li></ul><ul><li>Effect of deforestation: </li></ul><ul><ul><li>soil erosion and infertility </li></ul></ul><ul><ul><li>destruction of habitats </li></ul></ul><ul><ul><li>Breakdown of nutrient cycle </li></ul></ul><ul><li>As the soil loses its fertility, grazing land becomes poor and so more land is needed to feed the same number of cattle… more forest is destroyed. Cattle ranching cannot be managed in a sustainable way as the soil is no longer capable of growing grass </li></ul><ul><li>Ranching is now restricted to certain areas </li></ul>
  6. 6. 1994 Describe what can be seen and say what is happening (4 marks)
  7. 7. 1994 Describe the features of the human and natural landscape shown in the photograph (4 marks) Describe the local and worldwide problems suggested by the landscape changes and activities shown (5 marks)
  8. 8. Timber exploitation at Paragominas <ul><li>Logging companies have felled hardwood trees for furniture markets in MEDCs </li></ul><ul><li>Timber is a valuable source of income for Brazil. </li></ul><ul><li>Trees are felled with chain saws and then collected by skidders to be taken to saw mills in Paragominas. </li></ul><ul><li>Wood is sold in Brazil, high quality timbers are exported. </li></ul><ul><li>Environmental damage is caused because: </li></ul><ul><li>When a selected tree crashes down it brings down others </li></ul><ul><li>Bulldozers destroy surrounding vegetation </li></ul><ul><li>Trees do not grow back along tyre trails and wind channelled brings down more trees </li></ul><ul><li>Little attempt made to replace the deforested areas </li></ul><ul><li>This activity can only become sustainable if </li></ul><ul><li>Selective logging takes place </li></ul><ul><li>Replanting of trees takes place </li></ul>
  9. 9. Sustainable logging <ul><li>Do not fell trees under a minimum circumference </li></ul><ul><li>Do not exceed the maximum number of trees per ha that they are allowed to cut </li></ul><ul><li>Restrict the use of bulldozers and heavy destructive machinery </li></ul><ul><li>Develop the use of helilogging – very expensive </li></ul><ul><li>Agroforestry – plant traditional fruit trees and other crops in between rows of trees where logging has taken place. This keeps soil fertile and provides indigenous people with an income and food source </li></ul>
  10. 10. Mining <ul><li>There are vast quantities of minerals in Amazonia: </li></ul><ul><li>Bauxite </li></ul><ul><li>Managnese </li></ul><ul><li>Iron ore </li></ul><ul><li>Tin </li></ul><ul><li>Gold </li></ul><ul><li>Nickel </li></ul><ul><li>Copper </li></ul><ul><li>Silver </li></ul><ul><li>Molybdenum </li></ul><ul><li>These are mined using open cast methods. </li></ul><ul><li>Extracting these causes large scale destruction and pollutes rivers </li></ul>
  11. 11. Mining in Carajas region <ul><li>Open cast method of mining </li></ul><ul><li>Large excavation hole 4.1km long </li></ul><ul><li>300m wide </li></ul><ul><li>400m deep </li></ul><ul><li>15m high step like benches </li></ul><ul><li>66% pure iron </li></ul><ul><li>Crushing and processing plant, railway line to coast. </li></ul><ul><li>Tucurui HEP scheme </li></ul><ul><li>Markets are Europe, North America and Japan </li></ul>
  12. 12. June 2005 What economic activity is shown in the photograph? (1 mark) How has the environment shown and that of the surrounding areas been affected by this activity? (4 marks)
  13. 13. Impact of human activities <ul><li>Rate of deforestation 15ha (15 football pitches) cleared every minute </li></ul><ul><li>Loss of biodiversity </li></ul><ul><li>Decrease in Amerindians </li></ul><ul><li>Increased soil erosion </li></ul><ul><li>Climate change </li></ul><ul><li>Change in composition of atmosphere </li></ul><ul><li>****Which are local, regional and global effects? </li></ul>
  14. 14. Impact on the environment <ul><li>Clearance of large numbers of trees </li></ul><ul><li>Loss of soil fertility </li></ul><ul><li>Increased soil erosion </li></ul><ul><li>Endangered species </li></ul><ul><li>Loss of wildlife habitats </li></ul><ul><li>Silt added to rivers leading to flooding </li></ul>
  15. 15. Impact on climate <ul><li>Air pollution – carbon, sulphur and nitrous oxide emissions. This can increase local acid damage to plants </li></ul><ul><li>Fewer trees > less transpiration >so less water vapour in the atmosphere > less condensation and rainfall. Climate becomes drier > fewer trees > desertification </li></ul>
  16. 16. Deforestation increases global warming <ul><li>Clearing of land by burning trees adds carbon dioxide to the atmosphere </li></ul><ul><li>With fewer trees growing, less carbon dioxide is removed from the atmosphere </li></ul><ul><li>Amount of CO2 in atmosphere increases which traps heat trying to leave the earth so raising its temperature. </li></ul>
  17. 17. Impact on Indians <ul><li>Less forest to use for their farming, hunting or gathering </li></ul><ul><li>May have to retreat further into the forest </li></ul><ul><li>Tribe return to a chagra before it has had time to recover so food supplies are reduced causing starvation </li></ul><ul><li>Leave tribe to move to look for work in towns – this is hard as they do not have the skills </li></ul><ul><li>Die from imported diseases e.g. measles </li></ul><ul><li>Rivers used for water supply are polluted. </li></ul>