1 & 2 Alaska - Periglacial and ELSS

How large is the Alaskan tundra?

8 million km2

What percent of oil used in the USA is imported?

40%

What are the biggest suppliers of oil to the USA?

Canada, Mexico and Saudi Arabia

Why is importing oil an issue for the USA?

It undermines the energy security of the USA, as if they rely on countries for their supply of oil, then there are political implications that make them more vulnerable. For example they could be black mailed into doing things by other countries that are compromising.

Why has the USA increased exploration of potential oil fields?

They want to decrease their reliance on other countries, particularly Saudi Arabia, for their oil, as it makes them vulnerable.

What is the Willow Project?

President Biden has put forward a bill to introduce the ‘Willow Project’, which is expected to extract 600 million barrels of crude oil from an area in Alaska called the National Petroleum Reserve. It is an $8 billion project that is being protested against because of its potential increase climate change through not only gas flaring, but also through the combustion of the fuel itself. The area of Alaska is the USA’s largest single expanse of pristine land.

What is the Arctic Wildlife Refuge (AWR), and what is the danger associated with it?

* The AWR is a protected area in Alaska that covers an area of over 78,000 km2
* It is the largest wildlife refuge in the USA
* It is home to a variety of species including bears, moose wolves and eagles
* Currently there are no roads in the refuge
* However, there is ongoing debates as to whether to exploit the 12 billion barrels of oil that the refuge contains, and this is the risk associated with it

What is the impact of oil drilling on the material flows in the periglacial landscape system?

Material flows are affected by:

* The use of gravel pads to insulate roads. The gravel must be extracted from local river beds which changes how sediment moves downstream and also reduces erosional processes.
* Gravel extraction from aquifers can cause decreasing ground water levels

What is the impact of oil drilling on the energy flows in the periglacial landscape system?

Energy flows are affected by:

* The release and burning of gas during drilling. Some gases are burnt (==flaring==), and others are vented directly into the atmosphere. The gases released from this process include CO2 and methane, which are both important greenhouse gases that contribute to the enhanced greenhouse effect
* The production of heat from the extraction and transportation of oil, as well as other associated infrastructure (e.g. roads, houses etc.). Urban heat islands can form, for example Barrow, which is on average 2.2C hotter than the surrounding area. Heat from domestic heating systems in poorly insulated buildings os a major contributor to the heat island effect. There have been 9% fewer days if temperature fluctuations around 0\*C recorded since drilling began

How does oil drilling affect periglacial landforms

Oil drilling affects periglacial landforms primarily by the deepening of the active layer. Landforms such as solifluction lobes, thermokarst and alases become more widespread and form more quickly. This is because when infrastructure is poorly insulated it warms the active and causes it to deepen. This is also exacerbated by climate change.

What are solifluction lobes?

The heat released by buildings and infrastructure (e.g. roads, sewage and water pipes, oil pipes) can cause subsidence and the increased movement of the active layer. Solifluction lobes form when the thawed, saturated active layer moves downslope forming tongues of debris.

What is thermokarst?

Thermokarst is a landscape dominated by surface depressions due to the thawing of ground ice

What are alases?

Alases are depressions in the active layer that develop due to the thawing of permafrost. They develop due to the widespread thawing of ground ice causing large-scale subsidence. They may contain lakes.

What is a subsidence statistic?

On the North Slope of Alaska, research into thermokarst found that subsidence rates are on average of 3-4cm a year.

What is the climate in Alaska like?

* Mean temperatures are below -15\*C (in the tundra). Average temperatures only exceed 0\*C in around 3 months of every year
* Temperature can reach -40\*C
* Long hours of daylight in summer
* Low annual precipitation (less than 100 mm in most areas)

What are the main features of the water cycle in Alaska?

* Low annual precipitation
* Low storage of water in the atmosphere due to low evaporation
* Limited transpiration (esp. in winter) due to lack of vegetation and short growing season
* Low evaporation as much of the sun’s energy is spent melting snow. Water is also frozen for most of the year
* Limited groundwater and soil moisture stores
* Accumulation of ice and snow during the winter months, which then melts, causing a sharp increase in river flow
* Extensive wetlands in the summer. Alaska has over 3 million lakes

What are the main features of the carbon cycle in the tundra?

* It is a carbon sink, with Alaskan soil containing 5x more carbon than the above ground biomass
* There is low NPP, despite the plants that grow in the summer. This is due to the low temperatures and frozen ground 8 months a year. The NPP per year is 200g per m2
* During the growing season, plants input carbon-rich litter into the soil, which is then frozen during the winter months, which is what makes Alaska such an effective carbon store

What changes have occurred to the environment and how have they affected the carbon cycle in the tundra?

The Earth is warming, which is shown by the increasing of the average temperature of the Earth. This is because melting permafrost means that CO2 is released by microorganisms that live in the carbon rich soil by respiration.

However the warming is also stimulating plant growth, which removes oxygen from the atmosphere. Therefore the overall effect of this warming is unclear, but it is thought that Alaska could become a carbon source, rather than a sink.

What are the physical factors affecting the water cycle?

* Average temperatures are well below freezing for most of the year so most water is stored as ground ice in the permafrost layer. During the summer, the active layer deepens and more permafrost melts, so liquid water pools on the surface. This is because of poor drainage due to the impermeable permafrost beneath the active layer. In the summer there is evaporation from standing water, but in the winter it is locked up in permafrost. Humidity is low and precipitation is scarce
* Permeability is low due to the permafrost and igneous rock types
* The landscape of Alaska is fairly flat, which allows water to collect on the surface during summer

What are the physical factors affecting the carbon cycle?

* Carbon is mainly stored as partly decomposed vegetation frozen in permafrost. Most of this has been locked away for at least the past 500,000 years
* Low temps and the unavailability of liquid water mean that total carbon store of biomass is relatively small. The growing season lasts around 3 months and photosynthesis and NPP are low
* Low temps and water logging slow respiration and the decomposition of decaying plants, which reduces the flow of CO2 to the atmosphere
* Due to the impermeability of the rock, its mineral content and porosity, as well as permafrost, the rock type exerts little influence on the carbon cycle

What causes the melting of permafrost (due to oil and gas extraction)?

* Construction and operation of oil and gas installations, settlements and other infrastructure diffusing heat directly into the environment
* Dust deposition along roadsides darkens the surface of the snow, stopping the albedo effect and causing the increased absorption of sunlight
* Removal of vegetation cover which insulates permafrost

How does oil and gas production affect the ==carbon cycle== in Alaska?

* Permafrost melting releases CO2, and on the North Slope of Alaska, these losses from permafrost vary from 7-40 million tonnes per year. Gas flaring and oil spills also inputs CO2 into the atmosphere
* The destruction of tundra vegetation reduces photosynthesis and the uptake of CO2 from the atmosphere
* The thawing of soil increases microbial activity

How does oil and gas production affect the water cycle in Alaska?

* Melting of permafrost and snow cover increases run off and river discharge, increasing the likelihood of flooding
* In summer there is increased evaporation from meltwater pools, lakes and wetlands
* Mining of gravel for construction creates artificial lakes which disrupt drainage and expose permafrost to melting
* Artificial lakes near Fairbanks have experienced 15m of permafrost thaw in the last 60 years
* Drainage networks are also disrupted by road construction, as water cannot infiltrate into the soil through tarmac

How much have the emissions of CO2 from the North Slope permafrost increased?

Since 1975 they have increased by 73%

What are the management strategies to moderate the impact on the water and carbon cycles?

* Insulated gravel pads under roads and other infrastructure which protects the permafrost from melting to some extent e.g. the Spine Road at Proudhon Bay lies on a 2m deep pad
* Construction of buildings and pipelines elevated on piles which allows cold air to circulate beneath the structures, which provides some insulation against heat generating buildings and pipes
* Drilling laterally beyond drilling platforms, as new techniques allow oil to be accessed several km from the drilling site which means that fewer drilling rigs are required so the impact on the permafrost is reduced, for example Shell’s “snake drill”
* Computers can detect oil rich regions remotely which means that fewer exploration wells are needed which reduces the impact on the environment
* Refrigerated supports e.g. Trans Alaska Pipeline