Alaska

• Context

  Alaska has about 3000 million barrels in proven reserves.

  The 1300 km Alyeska pipeline, which runs from Prudhoe Bay (in the North coast) to the ice-free port of Valdez on the south coast, transports oil up to 1.4 million barrels per day.
• Need for oil

  In 2014 the USA consumed 6.95 billion barrels of oil products, with the demand only increasing.

  40 % of the USA’s oil supply comes from imports; this decreases their energy security.
• Reserves

  exploration of potential oil fields in Alaska has been permitted by the government.

  Area 1002 in the Arctic National Wildlife Refuge contains over 16 billion barrels; 6 billion are able to be extracted using currently available technology.

  Extracting oil results from Area 1002 means that there will be increased employment opportunities and that the existing Alyeska pipeline can be used.
• Impacts energy flows on the periglacial landscape system

  Release and burning of gas during drilling; carbon dioxide through flaring, methane vented without burning to atmosphere.

  Production of heat from the extraction and transportation processes, as well as associated infrastructure; mean temperatures in Alaska are 2.2 degrees higher than surrounding on rural areas.
• Impacts material flows on the periglacial landscape system

  Use of gravel pads as an insulating base layer for road construction. Loss of gravel from river system effects gravel deposit rates, and the equilibrium between erosional and depositional processes in the river system.

  Ground water levels fell by a meter in an area extending 2 km from the extraction site.
• Changing landforms

  Heat released by buildings and infrastructure can lead to the thawing of permafrost, and a longer period of melting of the active layer.

  If a building is constructed directly onto the ground surface, some of the heat produced transfers through the floor to the ground, melting the permafrost. This results in subsidence and an increase in the mobility of the active layer, allowing solifluction to take place.
• Periglacial

  A landscape that undergoes seasonal freezing and thawing, typically on the fringes of past and present glaciated regions.
• Thermokarst


  Surface depressions due to the thawing of ground ice.

  Extensive areas of hummocky ground interspersed with waterlogged hollows. Depressions may fill with water to form shallow thaw lakes, usually less than 5 m deep and 1 to 2 km wide.

  Subsidence rates averaging 3 to 4 cm per year.
• Alases

  Large scale thermokarst.

  Flat-floored, steep-sided depressions ranging from 5 to 50 m in depth and 100 m to 15 km in length.

  Develop from widespread thawing from ground ice causing large scale subsidence.

  These depressions may contain lakes.
• Alas Valleys

  Occur when several alases combine.

  Can be many 10s of km in length.
• Causing thawing

  Thawing of the ground ice can be caused by climate change, but also by direct human interference.

  Removal of vegetation for resource extraction or construction purposes decreases the insulation of ground ice. This leads to it thawing to greater depths, creating a thicker active layer, producing much deeper and more extensive subsidence.