human influences

• • Sustainable resource: one which is produced as rapidly as it is removed from the environment so that it does not run out
• • Sustainable development: development providing for the needs of an increasing human population without harming the environment
• • Sustainable development requires:
  • Management of conflicting demands
  • Planning and co-operation at local, national and international levels
• • Some resources can be maintained, limited to forests and fish stocks.
• • Some resources can be sustained using:
  • Education
  • Legal quotas
  • Re-stocking
• • Water: used to grow food, keep clean, provide power, control fires and to drink. We get water constantly through rainfall but we are using up planet’s fresh water faster than it can be replenished.
• • Fossil fuels: need to be conserved as they will soon run out, they should be therefore replaced with green forms of energy.
• • Water and fossil fuels are examples of natural resources
• • Water recycling: water from sewage can be returned to environment for human use by sanitation and sewage treatment
• • Paper recycling: sent to special centres where it is pulped to make raw materials for industry
• • Plastic recycling: fossil fuels, bottles → fleece clothing
• • Metal recycling: mining takes a lot of energy so recycling saves energy
• • Species and habitats need to be conserved because:
  • Organisms have value in themselves (ethical value)
  • Value to medicine
  • Genetic resources are useful to humans as well and are lost when species disappear
  • Each species has its role in its ecosystem; if it is removed, then the whole ecosystem could collapse
• • How do species become endangered?climate change, habitat destruction, hunting, pollution and introduced species
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  • If the population size of a species drops then variation decreases
• • How can endangered species be conserved?monitoring and protecting, education, captive breeding and seed banks
• • Conservation programmes include:
  • reducing extinction
  • protecting vulnerable environments
  • maintaining ecosystem functions, by nutrient cycling and resource provision, e.g. food, drugs, fuel and genes
• • Chemical waste and sewage in rivers results in water not being drinkable and eutrophication can occur
• • Sulphur dioxide dissolves in rain, causing acid rain which increases acidity of lakes and leaches aluminium out of the soil
• • Acid rain leads to:
  • Damage to fishes’ gills. Fixed by adding calcium hydroxide (slaked lime)
  • Destroys top of trees and aluminium damages tree roots, important nutrients leached away
  • SO2 poses health hazards for humans (asthma sufferers)
  • Damages limestone buildings and sculptures
  • Fewer crops can be grown on an acidic field (fixed by adding lime)
• • Herbicides (kill weeds): can be harmful to animals which eat the plants
• • Global Warming:
  • Increase in Earth's average temperature
  • Started as we began burning fossil fuels
  • Scientists believe fossil fuels are the cause – not proven yet
  • Increase in carbon dioxide and methane concentrations in atmosphere cause enhanced greenhouse effect, leads to climate change
• Eutrophication:

  • Fertilisers put in soil
  • Fertilisers with nitrates / detergents with phosphates leach into rivers & lakes after rain
  • Water plants grow more than usual
  • They block sunlight and kill plants underneath
  • Bacteria/fungi decompose remains using the O2 and decreasing the O2 concentration
  • Fish and other creatures die from oxygen starvation