Carbon cycle

• Positive feedback loops

  Amplify changes and increases equilibrium
• Negative feedback loop

  Restores balance in a system
• Positive feedback loop: Increased evaporation

  increased temperature > increased evaporation > increased atmospheric water vapour - GHG > enhanced greenhouse effect > increased temperature
• Positive feedback loop: reduced albedo

  increased temperatures > melting of glaciers > low albedo > increased solar radiation > increased temperature > further melting
• Positive feedback loop: Increased cloudiness

  increased temperature > increased evaporation > Increased atmospheric water vapour > increased cover of high altitude cirrus clouds > increased heat trapped > increased temperature
• Positive feedback loop: Release of methane hydrates

  increased temperature > increased ocean temperature - the heat is absorbed by oceans> increased methane - as methane hydrates are broken down from the warm water > increased atmospheric methane through diffusion > enhanced greenhouse effect > increased temperature
• Positive feedback loop: Melting of permafrost

  increased temperature > increased GHG's - particularly carbon dioxide and methane > increased thawing permafrost - frozen to liquid stage > increased GHGs > increased temperatures
• Impacts of rising sea surface temperatures (SST) on marine ecosystems

  • Increasing SST > causes bleaching of coral reefs > kills coral reefs > Eg: In Indonesia 50% of coral reefs have been bleached
  • Increasing SST > shifts the habitants of marine species > Eg: UK SST have increased by 1.6° > cold water species like cod have to migrate northwards towards Iceland waters
  • Increasing SST > disrupts food chains >Eg: in Arctic ice, algae - the base of the marine food chain - can no longer survive in warm waters
  • Increasing SST > melts sea ice which is crucial for the survival of marine mammals
• Implications of climate change for people and the environment


  Desertification - Soil and land degradation can lead to:

  • infertile soils
  • surface soil eroded by wind and soil > no roots to hold surface soil in place > crops/ trees die
• The vulnerability of the environment from the impacts of climate change

  PHYSICAL IMPACTS:

  • More erratic rainfall> increased droughts > decreased crop yield > land degradation and desertification > Eg. Sahel
  • Melting glaciers > decreased meltwater > decreased irrigation > decreased crops > Eg. North India
  • Sea level rise and storm surges > increased flooding > decreased crop yield > land degradation > Eg. Storm surges in Bangladesh
  • Thawing permafrost > increased meltwater from sea ice > increased flooding > Eg. Arctic
• The vulnerability of people from the impacts of climate change

  HUMAN IMPACTS:

  • Level of development > LIDC's have increased vulnerability but decreased resilience > unable to mitigate > Increased impact from climate change > Eg. Bangladesh
  • Demographics > young, old, ill people have increased vulnerability > increased excess deaths > Eg. Europe summer 2003: extreme heatwave
• The ecosystems most vulnerability from the impacts of climate change

  • Tundras > melting of permafrost
  • Coasts > low lying coastal regions which are more susceptible to sea level rise
  • Hot, semi-arid environments > further extreme conditions
• Why is plant productivity vulnerable to climate change?

  • CC leads to more erratic rainfall > causes droughts > decreases crop yield > land and soil degradation and desertification > crops will die > Eg. Sahel in Northern Africa - land was abandoned due to severe land degradation
  • CC leads to an increase in temperature > decreases meltwater > decrease in irrigation supply > subsistence farmers rely on glacial meltwater streams to irrigate their crops > therefore they lose their supply > decrease in crop yield > Eg. North India experienced water shortages