What is PERMAFROST, its characteristics, where it is and its DEFROST

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After the fires of 2022 in regions near the Arctic Circle, the media and dissemination have shared more information about the thawing of permafrost, also called permafrost, permafrost or permafrost. This is a fact that has alarmed the scientific community for decades.

In this Green Ecologist article we explain what is permafrost, its characteristics and where is it. In addition, we also talk about what happens with the thawing of permafrost and what are its global consequences.

What is permafrost

It is known as permafrost when frozen ground. It is difficult to classify it since it can have different characteristics and shapes, since it can both be composed of solid rock, sediments or sandy and rocky soils as well as rich organic ones. All possible types of soils that are considered permafrost must be frozen, which implies that they must have been under the freezing point of water 0 ºC or 32 F for a minimum of two consecutive years. The concentration of water is not decisive either, as long as they have a slight percentage of frozen water it is enough.

Permafrost characteristics

Next, we highlight the most relevant permafrost characteristics to get to know this type of soil well.

  • Around the 20% of the earth's surface is recognized as permafrost, which was formed during the last ice age.
  • It is part of both the cryosphere to be frozen, and therefore of the hydrosphere, as of the geosphere to contain rocks and soil.
  • It has an active layer, more superficial, and another inactive, deeper. The active layer It stands out for having a depth of between 30 to 200 cm. It melts in the summer season and refreezes in winter. In it, plant life develops depending on how far its roots can penetrate and be supplied with water. For this reason, vegetative landscapes can vary from tundra regions to boreal forests or taigas. The inactive layer It is the one that remains frozen and can go up to 1,500 m deep.
  • The aforementioned effect can generate, over thousands of years, polygonal patterns on the earth's surface, associated with the contraction and expansion of the soil due to temperature differences.
  • The ice it has acts as cement, making the components of the soil stay together, so its melting can generate landslides or landslides. It also acts as an insulator, so that some lakes and wetlands can disappear when they infiltrate the ground due to the loss of ice.
  • If the hotspot is very deep, it cannot be refrozen in the winter season, causing the permafrost to recede.

Where is the permafrost

After knowing what it is and its main characteristics, it should be clarified where is the permafrost found. It is found in cold climates, in high latitudes and in high mountain areas with high altitude. It is located in the circumpolar zones from Russia, Canada, Alaska, China, Greenland, Scandinavia, and Antarctica, plus high mountain areas like the Pyrenees, the Alps or Tibet, among others.

What is permafrost thaw

Due to the Earth's temperature increase, the cryosphere melts. Regarding this increase in temperatures, a point of no return is being reached and the active permafrost surface is getting deeper and deeper.

It is one of the greats carbon sinks of the planet, so it is expected that the carbon retained in it is four times higher than that found in the atmosphere. Its release would imply a very drastic increase in the greenhouse effect, motivating a feedback loop.

Since the last Ice Age, organic matter has been accumulating in it, from dead plants and animals. This organic matter has been preserved by freezing in permafrost for millions of years. To the melt the permafrost, this organic matter is exposed to decomposing microorganisms that, when found in anaerobic environments (with a lack of O2), emit CO2 and CH4 in higher concentration, due to the process of methanogenesis or biomethanization. Unfortunately, the permafrost methane, and from other sources, it has a power 25 times greater than CO2 on the greenhouse effect.

In addition, the methane gas hydrates that were retained in the permafrost are also gradually released and rise as it thaws.

What are its consequences if the permafrost melts

The gradual thawing of permafrost is an irreversible factor that generates major problems such as those related to the loss of soil structure. The main consequences of the thawing of permafrost associated are:

  • Damage to infrastructures, due to the loss of cohesion of the soil.
  • Coastal erosion.
  • Landslide due to the instability of the slope.
  • Increase in the greenhouse effect due to the escape of GHG (Greenhouse Gases) that were retained (CO2 and CH4).
  • Damage and loss of biodiversity and the ecosystem.
  • Sea level rise and related catastrophes.
  • Appearance of pathogenic microorganisms that were in a latent state with reduced metabolism, such as viruses.
  • Migration of people due to the instability of the area.
  • Associated economic problems.

An example of the consequence of the thawing of permafrost related to the appearance of latent pathogenic microorganisms is that it is estimated that, in 2016, the anthrax outbreak that occurred in the Yamal Peninsula was due to this environmental problem. The reindeer must have ingested the virus in permafrost and later they transmitted it to humans, when they ingested their meat.

If you want to read more articles similar to What is permafrost, its characteristics and where is it?, we recommend that you enter our category of Curiosities of the Earth and the universe.

  • Ming-ko Woo (2012) Permafrost Hydrology, Kimberly P. Wickland, 1,2 Robert G. Striegl, 3 Jason C. Neff, 4 and Torsten Sachs.
  • Kimberly et al. (2006) Effects of permafrost melting on CO2 and CH4 exchange of a poorly drained black spruce lowland.
  • We Are Water Foundation (2022) The thawing of permafrost: the threat of prehistoric mud. IAWA.
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