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What is permafrost?

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Permafrost definition

What is permafrost? As its name suggests, it is something permanently frozen. Merriam-Webster dictionary offers the following permafrost definition: “a layer of soil that is always frozen in very cold regions of the world”. Most of it is in Russia’s Siberia, Alaska, northern Canada and Greenland.

Permafrost definition

Permafrost depth

Permafrost depth can reach over 1,400 meters. The permanently frozen ground, including soil, rock or sediment, is often covered by the “active layer” of between 0.6 and 4 meters that thaws in summer. What is permafrost of the Arctic Ocean? It is permafrost that lies underwater, on the continental shelves of the continents encircling the Arctic Ocean.

Permafrost depth

Permafrost melting

Permafrost melting can occur should global temperature rise by 1.5 degrees centigrade. What is permafrost? If the ground remains below 0 degrees centigrade for two consecutive years, it qualifies as permafrost. The top levels of permafrost form quite quickly, while the deeper it goes, the longer it takes for the ground to freeze.

Permafrost melting

Siberian permafrost

Scientists nowadays are concerned with the melting of unique Siberian permafrost called yedoma. What is permafrost in Siberia? It is a frozen tundra dust, deposited during the ice age.  It is rich in methane gas – one of the main contributor to global warming. With the melting of Siberian permafrost, methane escapes into the atmosphere.

Siberian permafrost

Permafrost in Alaska

The thickness of the permafrost in Alaska can vary from just a few centimeters below the surface to going as deep as 300 meters. It is the thickest in the northern parts of the State. What is permafrost in Alaska like? In Interior and Western Alaska, the permafrost is often less than 30 meters deep. It may be absent in warmer places, for example, on the sunny southern hills slopes. In Southcentral and Southeastern Alaska, permafrost occurs only sporadically, in stand-alone masses that are often widely separated.

Permafrost in Alaska

Siberia’s permafrost is home to many unsolved mysteries. The latest is the appearance of huge craters on the Yamal peninsula that have attracted worldwide attention. Several scientific expeditions have visited the region in winter and summer. They’ve  conducted lots of tests but still can’t find an explanation for the mysterious phenomenon.