Case study - Alaska

• What is the background of Alaska?

  State in the US

  Mountainous and found the Arctic Circle

  Many periglacial areas with huge oil reverses

  The Yukon river flows across to the Arctic sea
• Why are cold environments fragile?

  Due to the harsh climates so they take longer to recover from changes
• What aspect of cold environments are very fragile? - Example

  the flora in the ecosystems - lichen only grow at a rate of 2mm per year, so they are easily damaged
• What is the buffer zone?

  This is the top layer of the active layer that is usually covered with vegetation, lichen and organic material
• What does the buffer zone control?

  The thermal energy exchange between the ground and atmosphere
• Why is the thermal exchange between the ground and atmosphere important for the permafrost?

  If higher levels of heat is transferred to the active layer, then there will be more melting of the permafrost
• Why is oil extracted in Alaska?

  Areas in the Arctic circle are rich in resources; Alaska has around 300 mil barrels of oil
• How much of the worlds undiscovered oil and gas are found in the Arctic circle?


  13% and 30%
• Which town in Northern Alaska has turned into a large oil town?

  Prudhoe Bay is now wealthy due to the finding of crude oil in 1968
• What is the Trans-Alaskan pipeline?

  a 1200km long pipeline which transports oil from Prudhoe Bay to the ice free port of Valdez
• Why was the Trans-Alaskan pipeline built?

  In response to the 1973 Oil crisis, the US wanted to be self-sufficient with it’s oil however 40% of its oil is still imported
• How many mountain ranges does the pipeline cross? And how much of the pipeline is built on stilts?


  3; 600km
• In 2014 how many barrels of oil products were consumed?


  6.96 bil
• Which area is protected in Alaska from oil companies?

  Area 1002
• Why is Area 1002 is protected and why do oil companies want the area?

  It is home to lots of wildlife and the indigenous people - Gwich’in Indians.

  Oil companies want it since it may contain 16 bil barrels of oil
• What is the Alaskan govt planning to do with the protected areas?

  Auction them off to oil companies
• How do the local people benefit from the oil companies?

  The sovereign wealth fund gives money to the people - 2022: $3284
• What is the main cause of the permafrost landscape changing so rapidly?

  Human activities: oil extraction, settlement, climate change
• What is the impact of oil extraction and mining?

  When companies mine for oil, they disturb the wildlife. The wastage is placed into drilling stumps into the permafrost which is disturbing and degrading it. - Mackenzie Delta upland regions have degraded permafrost
• What is the impact of climate change?

  With warmer temperatures, more heat is transferred to the permafrost. Permafrost contains and stores carbon (undecomposed organic matter) which is released when it melts - CO2 and methane
• What is the impact of settlement?

  When houses are built, the vegetation and snow is removed, leading to less insulation and more heat exchange between the atmosphere and the permafrost causing it to degrade.

  Central heating buildings and pipes also increase the heat transfer to the ground - thaw movement can damage pipelines and the infrastructure

  Older buildings don’t insulate the permafrost so more heat enters it - can lead to shorter summers and the upper permafrost rises (Arctic higher is 1m higher)
• What are the main problems to do with permafrost melting?

  If the permafrost melts during warmer summers, it may not re-freezes during winter Thaw settlement - the ground surface subsides when permafrost thaws. This produces irregular ground with a downslope displacement and topographic depression

  Alases and Thermokarst landscapes develop
• What are Thermokarst?


  this the process by which distinctive landforms result from the thawing of ground ice. It contains surface depressions which are water logged. (Also contains ancient methane.)
• Define alases


  large scale flat floored, steep sided depressions (5-50m depth, 100m-15km long)
• How do alasas form?


  Large scale thawing of ground ice results in large scale subsidence. Valleys can form where several alases combine; small scale lakes can also form in the depressions
• How do human activities promote the rate of Thermokarst landscape development and why are they bad for inhabitants?

  Human activities increase the rate of frost heave, frost thrust, ice lens development, solifluction; people can’t live on these unstable areas
• What is the problem of a deeper active layer?

  can cause:

  more permafrost degration, increased slope instability, increased thermokarst landscape development
• How much of the Northern Hemisphere contains permafrost?

  15%
• How much faster is the Arctic is melting comparing to the rest if the world?

  3x
• What factors influence the active layer’s thickness?

  Surface temperature

  Soil moisture content

  Vegetation cover

  Thickness/coverage of snow
• How are the Alaskan Gwich’in Indians impacted by the oil development?

  The people used to use the land for whaling which was a big part of their society but the impacts of climate change is impacting the wildlife and the ice coverage and oil companies are buying up the lands
• How does human settlement impact energy flow?

  the construction of infrastructure can easily alter the thermal balance of the ground which results in the thaw of permafrost and ground subsidence; the urban heat island effect is when the central heating of houses warmer the permafrost impacting the energy transfer
• What is an example of a settlement that has altered the energy flow?

  Barrow in Alaska - 9% fewer days of temperature fluctuations around 0 as the population has changed from 300 (1900) to 4600 (2000)
• How does oil extraction impact the energy flows?

  Flaring is when CO2 is released from power plants to stop the pressure building up - releases lots of greenhouse gases which impact the amount of heat energy transfer
• How does thaw settlement impact the landscape?

  The thawing of permafrost means longer ablation periods and more subsidence and increased mobility of the active layer that results in solifluction
• Define solifluction lobes


  the moving material loses energy on a lower gradient tongues of debris are formed
• Explain the formation of solifluction lobes


  When the surface layer melts in summer forming the active layer, it becomes mobile as it is saturated due to the impermeable permafrost below

  The movement produces lobes forming a terraces of stair arrangement

  This moves downslope and is slow moving - 0.5-5cm/year