4a. Human activity causes change within periglacial landscape system

Question 1

CASE STUDY: human activity in a periglacial system?

Answer 1

Oil extraction in Alaska

Question 2

What is the name of the oil pipeline? How long is it? How many barrels of oil are transported a day?

Answer 2

• the Trans Alasken Pipeline
• 1300 km long
• transports 1.4 million barrels of oil per day

Question 3

What is the name of the place the extraction is happening in?

Answer 3

Prudhoe bay

Question 4

Why is there a need for oil extraction?

Answer 4

• US has a lack of energy security (40% comes from imports)
• In 2019, US consumed 20,000 barrels of oil a day
• Need to start extraction in Area 1003 (Arctic) but concerns over wildlife

Question 5

What are the impacts on the periglacial system?

Answer 5

Affects energy flows:

• extraction & infrastructure/poorly insulated buildings release heat creating ‘heat island effect’
• eg. in Barrow, Alaska, 2.2 degrees higher temps
• burning of gas flares releases CO2 & methane - enhances greenhouse effect - traps radiation, raises temps

Question 6

What is the effect on changing landforms?

Answer 6

Thawing of permafrost:

• buildings directly on ground transfer heat through floor - melting permafrost
• causes subsidence (ground sinks)
• increases mobility of active layer, allowing for solifluction
• creates solifluction lobes

Question 7

What is the consequence on the landscape?

Answer 7

Creates a thermokarst landscape:

• landscape dominated by depressions due to melted permafrost, causing subsidence
• depressions fill with water forming thaw lakes
• removal of vegetation for extraction removes isolation –> deeper thawing –> deeper subsidence
• North slope of Alaska subsidence rate = 3-4cm per year