Periglacial 2: Environmental Change

Question 1

What is happening to the temperature of permafrost today?

Answer 1

Permafrost temperatures are increasing in Alaska, Canada and Russia.

Question 2

How much has temperature of permafrost in the Mackenzie River Delta Region increased sine the 1970s?

Answer 2

2 degrees celsius

Question 3

What is happening to the overall seasonal areal extent of permafrost?

Answer 3

Decreasing

Question 4

What is happening to the active layer thickness of permafrost layers?

Answer 4

Increasing

Question 5

What is happening to the active layer thickness in Russia and who found this?

Answer 5

Southward increase in the active layer thickness with increasing thawing days. Deepening of ~21cm between 1956-2008. IPCC, 2013

Question 6

What does the resilience and vulnerability of permafrost to climate change depend upon and who said this?

Answer 6

interactions between topography, water, soil, vegetation, snow (Jorgensen et al. 2012)

Question 7

What did Jorgensen et al. (2012) also note about the future prospects of permafrost?

Answer 7

That it does not seem like it will end that well

Question 8

What impact is permafrost thawing having upon thermokarst development?

Answer 8

In Alaska, and even Antarctica, there is a development of thermokarst landforms.

Question 9

What did Levy et al. (2013) identify?

Answer 9

Melting of a buried ice cliff 10x Holocene levels

Question 10

What impact is permafrost thawing having upon coastal erosion?

Answer 10

Thawing permafrost at the coast means that those mud-rich coasts with no beaches and a reducing sea ice extent means that erosion will increase

Question 11

What is happening in the Beaufort Sea in terms of coastal erosion?

Answer 11

Doubled between the periods of 1955-85 and 1985 to 2005. This has led to 1km recession over 50 years.

Question 12

What impact is permafrost thawing having upon rockfalls and landslides?`

Answer 12

permafrost thawing and draining talik ice is increasing the risk of sudden collapse which may induce more frequent rockfalls and landslides. In mountainous areas as well the permafrost line may be increasing in altitude which would also induce these events

Question 13

What impact is permafrost thawing having upon growing lakes?

Answer 13

Continuous permafrost is impermeable so precipitation is agglomerating on the surface of as pools. This will lead to wet thermokarst landscapes which because the rainwater is warmer than the underlying permafrost will mean that there will be increased melting

Question 14

What did Smith et al. (2005) note?

Answer 14

increasing area of lakes of 12% in Siberian permafrost zone

Question 15

What impact is permafrost thawing having upon disappearing lakes?

Answer 15

where permafrost thaws it can transition from continuous to discontinuous in characteristic. This will allow taliks to surface which will lead to lake drainage

Question 16

What impact is permafrost thawing having upon hydrological change and ecosystems?

Answer 16

Thermokarst processes can over saturate or dry ecosystems which can dramatically alter the landscapes and therefore the environment for Arcitc biota.
Similarly, the increased outwash of sediment through terrestrial erosion in to marine environments can disturb aquatic ecosystems

Question 17

What impact is permafrost thawing having for geotechnical issues?

Answer 17

Thawing permafrost makes the land unstable which can then damage infrastructure that relies upon it

Question 18

What knock-on impact is permafrost thawing having upon carbon release?

Answer 18

1. thawing of soils which contain a lot of carbon can be released to the atmosphere
2. the increased dryness of the tundra landscapes can induce fires which releases carbon from the organic matter

Question 19

How much carbon do northern soils contain?

Answer 19

1,700 billion tonnes - 2x as much in global atmosphere

Question 20

What are possible release mechanisms of carbon from Northern soils?

Answer 20

microbial decomposition and methane bubbling

Question 21

What was a major fire in the Arctic in 2007?

Answer 21

Anaktuvuk River Fire (2007)

Question 22

What was the significance of the Anaktuvuk River Fire (2007)?

Answer 22

It was the largest Tundra fire on record which doubled the cumulative area of Tundra forests burned since 1950

Question 23

How much carbon was lost by trees during the Anaktuvuk River Fire (2007)

Answer 23

2016 g C per metres squared

Question 24

What knock-on impact is permafrost thawing having upon methane release?

Answer 24

Warming can destabilise methane hydrates from subsea permafrost

Question 25

What is the significance of Methane as GHG and particularly from hydrates?

Answer 25

Methane is a much more potent GHG and the hydrate methance concentration is 164x higher than other sources. Furthermore, methane in this area is poorly quantified so could be even more

Question 26

What knock-on impact is permafrost thawing having upon nitrous oxide release?

Answer 26

Release of this gas from cores is 300x worse than release of carbon from permafrost

Question 27

What did Elberling et al. (2010) find?

Answer 27

Wetting and drying of a 10m permafrost core released nitrous oxide at rates similar to tropical rainforests

Question 28

What is another possible knock on impact of permafrost thawing?

Answer 28

Positive feedback between GHG release and warming

Question 29

What are 5 projection of future permafrost characteristics?

Answer 29

1. active layer thickening
2. surface area decrease
3. more thermokarst landscapes
4. Talik formation
5. Boundaries between continuous and discontinuous permafrost increasing