Week 11: Permafrost

Question 1

What is Permafrost?

Answer 1

Permanently frozen ground that covers almost 25% of the Earth’s surface

Question 2

What has happened with Permafrost due to rising temperatures from Climate Change?

Answer 2

• Permafrost has declined in area
• Stored carbon released as CO2 or CH4
• CH4 warms climate 30 times more than CO2

Question 3

What is the double effect of Permafrost thaw?

Answer 3

• Climate change is melting the Permafrost
• Organic matter released in melting Permafrost is affecting the climate in turn

Question 4

What within the permafrost binds soil particles like cement?

Answer 4

Ice

Question 5

What is PCF?

Answer 5

Permafrost Carbon Feedback - the amplification of anthropogenic warming due to carbon emission from thawing permafrost

Question 6

How is Polygonal ground and Pingos formed?

Answer 6

Where the ice content exceeds the saturated moisture capacity of the soil

Question 7

What are the three layers in Permafrost ground?

Answer 7

Surface: interface where heat and carbon fluxes enter or leave the ground

Active Layer: The layer of ground that is subject to annual thaw and freezing

Permafrost: the ground that remains at or below 0C for at least two consecutive years

Question 8

What is an Ice Wedge?

Answer 8

A crack in the ground formed by a narrow or thin piece of ice (caused by melting permafrost) and extends downwards into the ground several meters. Over the winter, the water in the ground freezes and expands, causing growth over many years.

Question 9

What is a Thermokarst?

Answer 9

When pingos begin to thaw and their surface collapses, causing depressions

Question 10

What are Pingos?

Answer 10

Ice cored hills, typically conical in shape

Question 11

What are Taliks?

Answer 11

Unfrozen zones within permafrost and can be closed or open depending on whether the talik is bounded by permafrost

Question 12

How will Permafrost thaw affect Hydrology?

Answer 12

Because the permafrost acts as an aquitard in the soil, its melting will change the hydrology of the ground

Question 13

What are two ways infrastructure in permafrost areas is built to be resistant to melting permafrost?

Answer 13

• building on stilts
• using themosiphons to transfer heat into the air and keep ground cool

Question 14

Why is the sea warming?

Answer 14

Because as ice melts, less of the sun’s energy is reflected back into the atmosphere, causing a large amount of warming within the ocean