2.2.b Arctic Tundra

  • Created by: lee8444
  • Created on: 06-02-20 08:48

The Arctic Tundra

  • 8 million km squared in Northern Canada, Russia and Alaska
  • The climate becomes more sever the higher the latitude
  • Negative heat balance for 8/9 months a year
  • Ground is permanantly frozen, only the top metre thaws in the summer
  • Permafrost underlies the majority of the Arctic
  • Temperatures plumet to under -40 degrees Celcius
  • For parts of the year the Arctic is in complete darkness for the whole day as the sunrise is below the horizon
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Current water cycle in the Tundra

  • Low annual prcipitation at under 350mm with most falling as snow
  • Small store of moisture in the atmosphere
  • Limited transpiration due to limited vegetation and short growing season
  • Cold temperature limits evaporation
  • Permafrost barrier prevents percolation and infiltration so there is a limited groundwater store
  • The active layer consisting of rivers, lakes and snow during the winter melts during the summer causing a peak in river flow
  • Temporary wetlands during the summer cannot be drained due to this reason
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Current carbon cycle in the Tundra

  • Permafrost is a vast carbon sink with 1600GT of carbon globally
  • Cold temperatures slow deposition storing the carbon in the permafrost
  • The largest fluxes of carbon happen in the summer when the active layer melts
  • Plants grow rapidly in the summer due to long hours of sunlight
  • Tundra biomass is low at 200g per metre sqyared per year
  • Tundra used to be a carbon sink
  • In recent times it has become a carbon source
  • This is due to global warming increasing methane being released and more decomposition
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Physical factors impacting the WC


  • Well below freezing for most of the year
  • Water is stored in the permafrost
  • Active layer thaws in the summer creating surface water
  • Low humidity all year round
  • Sparse precipitation


  • Meltwater creates small pools of water
  • Poor drainage due to no percolation or permeability of the permafrost
  • Crystalline rocks determine the geology of the tundra which isn't permeable


  • Minimal relief
  • Causes chaotic glacial deposits
  • Waterlogging in summer months
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Physical factors impacting the CC

  • Most carbon is locked in the permafrost as dead organisms for over 500,000 years
  • Low temperatures and limited water availability limits plant growth
  • Total carbon store in biomass is low
  • Low temperatures and waterlogging prevents decomposition slowing the rate of carbon being released into the atmosphere
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Oil and Gas production in Alaska

Prudhoe Bay

  • Oil and gas was discovred here in 1968
  • The harsh climate posed problems for the extraction due to the cold and long hours of darkness along with the melting of the active layer in the summer causing flooding
  • Drilling was needed due to the rising demand for oil and gas and the US wanted to be less dependant on other countries for their oil and gas
  • they made pipelines, roads, oil producion plants, power lines and gravel quarries in the 70s and 80s
  • By the 90s, the North Slope accounted for 25% of the USA's oil however it s now just 6% due to the high prices of extraction in Alaska
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Human impact on the WC

  • Localised melting of the permafrost due to
    • Construction and operation of installations diffusing hesat into the environment
    • Dust deposition causing the albedo affect
    • Removal of vegetation cover which insulates the permafrost
  • Increased run-off
  • Decreased lag-time
  • Increased risk of flooding
  • More extensive wetlands in the summer
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Human impact on the CC

  • Balance of carbon in the permafrost is changing due to the permafrost being extremely sensitive to changes in temperature
  • Permafrost melting releases carbon dioxide and methane causing a positive feedback loop
  • This is at 7-40 million tonnes per year
  • Gas flaring and oil spillages release more carbon dioxide into the atmosphere
  • Vegetation removal causes less carbon fixation by photosynthesis
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Management strategies in the Arctic (1)

Insulated ice and gravel pads

  • Roads and other infrastructure is built on top of insulating ice or gravel so the transfer of heat decreases so less permafrost is melted

Elevated buildings and pipelines

  • By elevating pipelines that contain oil at 65-85 degrees Celcius, less heat is transferred to the permafrost so less permafrost is melted

Drilling laterally

  • New technology and techniques allow construction to dill sideways
  • By drilling sideways from the same drilling point on the surface, fewer drilling sites are required greatly reducing the impact on the permafrost on the top of the Tundra
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Management strategies in the Arctic (2)

More powerful computers for detection of oil

  • This allows less exploration wells to be constructed so less of the permafrost is melted locally as the technology doesn't directly melt the permafrost

Refrigerated supports

  • The Trans-Alaska pipeline uses supports that are refrigerated to reduce the transfer of heat to the permafrost
  • Can also be used around buildings protecting the frozen environment from the hot oil
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