24 Arctic Tundra Case Study Human Impacts - Carbon Cycle

Question 1

How do the oil and gas industries contribute to releasing stored carbon to the atmosphere in Alaska?

Answer 1

• Poorly insulated pipelines, buildings, or equipment of oil and gas infrastructure diffuses heat to the ground and causes increased localised thawing of permafrost, which is a major carbon store in the tundra.
• Dust deposition alongside roads darkens the snow surface, increasing insolation. due to decreased albedo affect.
• The removal of vegetation, which reduces insulation (protecting from suns heat) for the permafrost, and increases the area exposed to insolation.
• These activities collectively increase the rate and expanse of permafrost thaw, releasing CO2 and methane gases to the atmosphere and depleting this store.
• 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 2

How does the transfer of carbon occur from permafrost to the atmosphere?

Answer 2

• The release of CO2 and methane from permafrost as it thaws transfers carbon from a long-term store to another from permafrost to the atmosphere.

Question 3

How does the removal of tundra vegetation affect the carbon cycle in Alaska?

Answer 3

• These industries degrade and destroy tundra vegetation, which decreases the amount of carbon stored in vegetation.
• The rate of photosynthesis is reduced as there are fewer plants, meaning that less CO2 is taken up by plants and more remains in the atmosphere.
• The thawing of soil increases microbial activity because of the warmer temperatures, increasing decomposition and releasing more CO2 to the atmosphere at a faster rate. The carbon that is stored in the soils is decreased and transferred.
• The slow growth of this vegetation means that regeneration takes decades, so the store will be affected long-term as it cannot be returned until it has grown.

Question 4

What is the climate feedback loop in the carbon cycle in Alaska?

Answer 4

• The thawing of permafrost and releasing of CO2, alongside destroying vegetation, gas flaring, and oil spillages, contribute to increasing global temperatures. As a result, permafrost melts even more, releasing more carbon to the atmosphere.
• These greenhouse gases contribute to global warming and cause a climate feedback loop that as temperatures increase, more carbon will be released and increase the temperature again. In the future, this means that climate change will continue to damage Alaska’s ecosystem long-term and its effects will be difficult to reverse. This may even result in a thermokarst landscape developing.

Question 5

What is the expected increase in soil decomposition rates as a result of the thawing of permafrost?

Answer 5

The thawing of permafrost is expected to increase soil decomposition rates by 4 to 10 times.

Question 6

What was the average annual temperature in Alaska in 2018 and how does it compare to the long-term average?

Answer 6

In 2018, Alaska experienced its second-warmest year on record, with the average annual temperature at 1.7°C above the long-term average.