Alaska oil extraction (glaciation) Flashcards
(14 cards)
type of landscape
periglacial
used by people
why does oil extraction take place?
-in the past it was extremely poor- 2/3 employed by the government
-in 1968 the largest oil fields in N America were found in Prudhoe Bay, production started in 1977 when the Trans Alaska pipeline was finished
-linked to defence spending eg in the 1st Gulf War in 1990 the worlds oil prices had soared & defence spending threatened to spiral put of budget so pressure was applied to open the Arctic National Wildlife refuge for drilling.
Trans Alaska pipeline
-70000 construction workers
-800 miles long
-elevated 420 miles(some underground)
-554 animal crossings
oil production
-20% of oil production for USA at its peak
-since 1977 over 12.8 billion barrels of oil have been transported
-peaked in 1988: 2 million barrels a day
-by 2005 production had fallen to below 1 million barrels a day
-only 3 billion barrels left recoverable now
oil consumption in the US
2023: 19 million barrels per day
imported 9 million barrels a day
advantages of oil extraction
-increases energy security, employment opportunities and helped grown the economy
-between 1980 and 1986 the 500000 population enjoyed $26 billion oil revenues
-could decrease the cost of oil for consumers
-could increase federal state and local tax revenues
disadvantages of oil extraction
-disrupts the active layer of permafrost –> thaws
-vulnerable “single product” economy
-disrupts wildlife and animals
-disrupts the native peoples way of life
impacts on flows of material and energy from human activities : material
-use of gravel pads
–>gravel is extracted from streams and river beds to be used as an insulating material for road construction
–>loss of gravel alters the rate at which gravel is transported and deposited further downstream
–>can also affect the equilibrium between erosional and depositional processes
–>hydrological processes effected: ground water levels fell by more than a metre in an area extending over 2km from the extraction site
impacts on flows of material and energy from human activities : energy
-increase in temp. by the release of gas during drilling
–>flaring: CO2 released and venting of methane
–>higher levels of terrestrial radiation being trapped in the lower atmosphere –> increased temps
-production of heat from the extraction and transportation processes and from the associated infrastructure
Urban heat island
Barrow
-mean temps were on average 2* higher that in the surround rural areas
-a max of 6* was measured on a calm day
-from poorly insulated houses and oil extraction
-9% fewer days of freeze thaw cycles recorded since drilling began
how human activity affects periglacial processes and landforms in Alaska
-permafrost experiences less variation in temp because it’s not directly exposed to the seasonal difference in air temp
-heat from buildings and infrastructure can lead to the thawing of permafrost and a longer period of thawing of active layer
-can result in subsidence and increase the mobility of the active layer allowing solifluction
-solifluction lobes form
how human activities affect Alaska s periglacial landscape
-thermokarst: landscape dominated by surface depressions due to the thawing of ground ice
- extensive areas of hummocky land interspersed with water logged hollows
-may form shallow thaw lakes
-on larger scales: alases- steep floored steep sided depressions that develop from widespread thawing of ground ice causing large scale subsidence
thawing of ground ice caused by
-can be initiated by climate change but always by more direct human interference
-removal of vegetation for resource or construction purposes decreases the insulation of ground ice
–> thaws to greater depths creating a thicker active layer and producing much deeper and more extensive subsidence
human activity that doesn’t affect the periglacial environment
every year 10s of thousands of Alaskan natives harvest, process, distribute and consume millions of pounds of wild animals and fish and plants through subsistence
-they have intimate knowledge of the land so can do it responsibly
