Permafrost
How is it related to the climate?
AWI(Alfred-Wegener-Institut)(2016, March 8)
Permafrost - what is it? [mp4]
Retrieved from: https://www.youtube.com/watch?v=lxixy1u8GjY
How is it related to the climate?
What causes the permafrost to melt?
Human-generated greenhouse gasses and artificial carbon emissions from industries (which amount to about 25 times the amount of carbon created by the Earth naturally) have raised the Earth's temperature, and have caused the permafrost to melt rapidly. Permafrost contains a lot of greenhouse gasses that, if released, would raise the overall global temperature as a result of the contribution towards global warming.
Slowly melting vs Rapidly melting
IMAGE CREDIT: Victor O. Leshyk
Why does permafrost contain a lot of greenhouse gasses?
This is because there are many dead bodies of animals deposited tens of thousands of years ago before freezing in the permafrost.
IMAGE CREDIT: Victor Leshyk, Center for Ecosystem Science and Society
Why does permafrost melting cause climate change?
As the increased climate change warms the Earth, frozen bodies will begin to decay, and greenhouse gasses such as carbon dioxide and methane will be released in large quantities.
< Temperature rise -> permafrost melt -> temperature rises more rapidly -> A larger amount of permafrost will melt. >
IMAGE CREDIT: AMANDA DEMME
When melting slowly over tens of thousands of years, there was no large amount of greenhouse gas at once, however when melting quickly due to human industrial activities, it emits 25 times more greenhouse gas than naturally emitted greenhouse gasses, which has a great impact on climate change.
IMAGE CREDIT: VICTOR OLEG LESHYK AT NORTHERN ARIZONA UNIVERSITY
IMAGE CREDIT: r Luca Galuzzi via Wikimedia Commons
How does Winter affect permafrost?
The relatively warm mid-latitude atmosphere pushes out the atmosphere of the polar region in the winter, resulting in a ring-shaped jet stream around the Arctic. Jet streams usually wrap around cold air in the Arctic region like air barriers to help keep the Arctic cold. However, as this barrier breaks due to climate change, the half of the northern hemisphere is getting colder, and high pressure cloud of Siberia makes winter temperatures increase in the Arctic.
So this would mean much less snow falling and dryer grounds. When snowfall decreases, it could result in high-temperature drying which leads to forest fires. This will happen in high-altitude areas near the North Pole and the South Pole (where the permafrost exists).
Since forest fires lead to an increase of carbon emissions, this cycle would contribute even further to climate change.
How does Summer affect permafrost?
Summer precipitation is gradually increasing, so in turn the permafrost layer is decreasing. There were 2,750 observations of the underground permafrost over the past five years, where it was found that cracks formed on the surface of the permafrost during the warmer, rainier summers. The higher levels of rain melts the frozen ground at a quicker speed, meaning that as the permafrost continues to decrease, it has even lower chances of refreezing.
