24 Arctic Tundra Case Study Human Impacts - Water Cycle

Question 1

Where is the North Slope in Alaska?

Answer 1

• The North Slope is a region in Alaska that stretches across the northernmost part of the state, from the Brooks Range mountains to the Arctic Ocean.

Question 2

How much Co2 and Methane does the North Slope lose from permafrost every year

Answer 2

• The North Slope loses approximately 7 to 40 million/tonnes/year of CO2 from permafrost thaw,
• and 24,000 to 114,000 tonnes/year of methane (CH4)

Question 3

How do the oil and gas industries affect the melting of permafrost and snow in Alaska?

Answer 3

• The oil and gas industries increase the melting of permafrost and snow as poorly insulated infrastructure causes heat from gas flaring to diffuse to the ground and raise local temperatures, creating an urban heat island effect.
• This increases surface runoff and therefore increases river discharge.
• A pipeline transporting hot fluids can generate an estimated 10-100 Watts per square metre of heat, which can diffuse up to several meters into the ground.
• For example the Trans-Alaska Pipeline System (TAPS) is a 800-mile pipeline that carries crude oil from Prudhoe Bay to the port of Valdez. The pipeline is above ground in some areas and buried in others, and it has pumping stations along the way to keep the oil flowing.

Buildings can also produce urban heat island effect, perhaps even bigger

Question 4

How does increased surface runoff affect water in the water cycle in Alaska?

Answer 4

• Increased surface runoff makes flooding more likely.
• Lakes and rivers have a larger surface area as a result, which increases evaporation and transfers water that has been stored in frozen permafrost and soils long-term to the atmosphere.

Question 5

How do artificial lakes disrupt drainage in the water cycle in Alaska?

Answer 5

• Strip mining of aggregates (sand and gravel) for construction creates artificial lakes, which disrupt natural river drainage networks and further expose permafrost to thaw.
• Road construction and seismic explosions used to prospect for fossil fuels also disrupt these networks.

Question 6

How does water abstraction affect the water cycle in Alaska?

Answer 6

• Water is abstracted from creeks and rivers for industrial use and the building of ice roads in winter, which reduces surface runoff and therefore reduces the amount of water stored on the Earth’s surfaces as the atmospheric store increases.

Question 7

How does increased atmospheric store of water affect precipitation in the water cycle in Alaska?

Answer 7

• Low annual precipitation is a key aspect of Alaska’s climate. A greater store of moisture in the atmosphere due to increased evaporation will increase precipitation levels as cold temperatures mean that little water can be stored here for long.

Question 8

How does permafrost thaw affect groundwater storage in the water cycle in Alaska?

Answer 8

• Permafrost creates low permeability as it is a barrier to infiltration, percolation, recharge and groundwater flow. These processes increase as permafrost thaws and allows the ground to become more permeable.
• As more water is freed from being frozen and can infiltrate the ground, soil moisture storage and groundwater storage increase.
• The presence of more water in the ground increases throughflow and groundwater flow, as temperatures continue to increase and permafrost continues to melt, because there is now more liquid water.

Question 9

How does melting affect water movement in the water cycle in Alaska?

Answer 9

• Melting releases water that has been locked away in storage long-term, such as in permafrost, and therefore its movement through processes increases.
• As a result of human activity in these industries, the water cycle in Alaska is becoming more mobile.

Question 10

North Slope and Alaska - Intro

Answer 10

• Alaska, located in the northernmost part of the United States, is characterised by a harsh climate with temperatures that only rise above freezing for four months a year and can reach as low as -30°C in the winter
• This climate also contributes to the presence of the Arctic tundra, which is almost treeless and has low levels of biomass and biodiversity
• As one of the largest oil and gas producing regions in the United States, the North Slope has seen significant development in the oil and gas industry since the discovery of oil in Prudhoe Bay in 1968.
• By the early 1990s, the North Slope accounted for nearly a 25% of all domestic oil production in the United States