Human influences on the environment

• What is a source of sulfur dioxide pollution in the environment

  A source of sulfur dioxide pollution in the environment is the combustion of fossil fuels that contain sulfur impurities, e.g. car exhausts
• Describe an environmental consequence of sulfur dioxide pollution. 

  Sulfur dioxide can combine with water droplets in the air to form acid rain.
• effects of acid rain on the environment

  Consequences of acid rain pollution include:

  • Damage to leaves, buds, flowers and roots of plants
  • Rivers and lakes can become acidic, resulting in death of aquatic organisms
  • Minerals can be leached into bodies of water, also killing aquatic organisms
• Carbon monoxide being released 


  Carbon monoxide is released when fossil fuels are burned with an insufficient oxygen supply. Burning impure fossil fuels can produce sulfur dioxide pollution.
• How is carbon monoxide pollution damaging to living organisms?

  Carbon monoxide is damaging to living organisms because it binds to haemoglobin inside red blood cells, reducing the oxygen carrying capacity of the blood. Breathing in carbon monoxide for extended periods can be fatal.
• greenhouse gas

  A greenhouse gas is a gas that absorbs infrared radiation from the Sun, trapping it in the Earth's atmosphere.
• increasing atmospheric greenhouse gases

  lead to an increase in average atmospheric temperatures.

  Greenhouse gases trap infrared radiation in the atmosphere, causing atmospheric warming.
• examples of greenhouse gases

  • Water vapour
  • Carbon dioxide
  • Methane
  • Nitrous oxides
  • CFCs
• What human activities increase atmospheric carbon dioxide levels

  Carbon dioxide is released by human activities such as:

  • Burning fossil fuels
  • Burning organic matter, e.g. wood and other plant materials
• methane 


  Methane traps more radiation per molecule than carbon dioxide, so is a powerful greenhouse gas.
• What human activities result in increased atmospheric methane

  Human activities that increase atmospheric methane are:

  • Farming cattle, which release methane as they digest grass
  • Growing rice in paddy fields
  • Disposing of waste in landfill
• greenhouse effect.


  The greenhouse effect occurs when radiation from the sun isabsorbed by greenhouse gases in the earth's atmosphere. This traps heat and warms the atmosphere.
• Greenhouse effect causation 


  Greenhouse gases occur in the atmosphere with no input from human activities, where they are essential for keeping the earth warm enough to support life. Human activities result in an enhanced greenhouse effect.
• What is the enhanced greenhouse effect


  The enhanced greenhouse effect is the increased warming of the earth's atmosphere beyond normal levels due to human activities.
• global warming 


  global warming refers to the long-term increase in the earth's average temperature, primarily due to human activities that increase the levels of greenhouse gases in the atmosphere
• consequences of global warming

  • Increasing ocean temperatures
  • Melting of polar ice caps
  • Rising sea levels
  • Extreme weather events
  • Habitat change / loss
  • Decreases in biodiversity
  • Increased spread of pests and diseases
• Global warming consequences- ocean temp 


  Global warming is increasing ocean temperatures, leading to impacts such as melting polar ice caps, rising sea levels and coral bleaching.
• What human activities can result in water pollution

  Human activities that result in water pollution are:

  • Release of untreated sewage into waterways
  • Allowing agricultural chemicals to run off fields into waterways
• consequences of untreated sewage runoff into water systems. 

  Consequences of untreated sewage runoff into water systems include:

  • Aerobic microorganisms use nutrients in sewage to fuel respiration, depleting dissolved oxygen levels in the water and leading to the deaths of aquatic organisms
  • Toxic chemicals in sewage can kill aquatic organisms
  • Dangerous microorganisms can be harmful to human health
• Eutrophication 


  Eutrophication is the process by which increased nutrient availability in a body of water leads to a decrease in dissolved oxygen levels.
• Which human activities can contribute to eutrophication?

  Human activities that can lead to eutrophication include:

  • Use of chemical fertilisers which run off into nearby water bodies
  • Release of untreated sewage into water bodies
• leaching

  Leaching occurs when nutrients are washed out of the soil and into bodies of water by rain. This is a particular problem when highly soluble chemical fertilisers are used.
• algal bloom

  An algal bloom is the rapid growth of algae that occurs on the surface of water bodies when nutrient levels increase. Algal blooms can can block out sunlight to deeper water.
• when algal blooms occur

  Algal blooms occur when nutrient availability in water bodies is high, e.g. due to sewage or fertiliser run off.
• How do algal blooms affect other aquatic plants

  Algal blooms block out sunlight, meaning that aquatic plants below the surface do not have enough light to photosynthesise. These plants are likely to die.
• What role do microorganisms play in the process of eutrophication

  The role of microorganisms in eutrophication is as follows:

  • Microorganisms use dead organic matter, e.g. dead algae and plants that have died due lack of light in deeper water, to fuel respiration
  • Microorganisms have a plentiful food source so they reproduce
  • Dissolved oxygen is used up by all the respiring microorganisms
• process of eutrophication

  The process of eutrophication is as follows:

  • Nutrient runoff results in an algal bloom
  • Many aquatic plants die because algae block light and plants cannot photosynthesise
  • Bacteria feed on dead plants and algae, using the dead matter to fuel respiration
  • High rates of aerobic respiration deplete oxygen levels in the water
  • Other aquatic organisms die due to a lack of oxygen