Geophysics

text Roman Desyatkin Doctor of Biological Sciences, Institute of Biological Problems of Cryolithozone SB RAS, Yakutsk

Different stages of thermokarst degradation of the middle taiga: the combination of small thermokarst landforms into larger ones

Photo: Roman Desyatkin

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Outcrops of ice wedges on the coast of the Laptev Sea

Photo: M. N. Grigoriev

Outcrops of ice wedges in Central Yakutia

Photo: Roman Desyatkin

Different stages of thermokarst degradation of the middle taiga: the appearance of shallow water bodies and the death of zonal vegetation

Photo: Roman Desyatkin

Different stages of thermokarst degradation of the middle taiga: young thermokarst basin - duedya

Photo: Roman Desyatkin

Different stages of thermokarst degradation of the middle taiga: the combination of small thermokarst landforms into larger ones

Photo: Roman Desyatkin

According to the World Meteorological Organization, compared to the second half of the 19th century, the average temperature on the planet has increased by 0.85°C. In high latitudes, where temperatures have risen even more, the effects of global warming are already visible and could be quite widespread.

The fact is that, as a relic of the Pleistocene glaciations, vast territories with frozen soils have been preserved on Earth. According to geocryologists, the area of the permafrost zone in the Northern Hemisphere is more than 22 million square meters. km, including continuous - 7.64 million sq. km, island - 14.71 million sq. km. More than 60% of Russia's territory is occupied by permafrost, its area is estimated at more than 11 million square meters. km. rice. 01 .

Fig. 1 Distribution of permafrost in Russia

The Republic of Sakha (Yakutia) is located in the center of the continental cryolithozone of Eurasia. The main part of the republic (80% by area) is located in the zone of continuous permafrost zone, where the thickness of frozen rocks is over 400?m, with a maximum in the Vilyuy River basin - 1500?m.

The thickness of the ice wedges in the Primorsky lowlands and on the islands reaches 50-80?m [ 01 ]. On the territory of Central Yakutia, the thickness of the ice wedges is 40–60?m [ 02 ].

An increase in the average annual air temperature by 2-3°C over the past decades has caused an increase in the temperature of the upper part of frozen soils by 0.4-1.3°C, which is associated with an increase in the depth of thawing and the activation of cryogenic processes.

As a result, in open and disturbed areas of the taiga zone, degradation of permafrost ice began with the formation of thermokarst landforms [ 03-05 ].

How warm has it become in Yakutia?

Climate warming causes a gradual expansion of animals and plants from south to north, including pests of cultivated plants and carriers of pathogenic viruses. The avifauna of Yakutia has increased by 47 species compared to the 1960s (18.8% or almost 1/5 of the previous composition). An inventory of the flora of the republic indicates the appearance here of new species of vascular (higher) plants, the distribution area of which was previously limited to the Baikal region and Transbaikalia.

The massive nature of this change in the habitats of wildlife indicates that the boundaries of natural zones have begun to move from south to north.

Global warming is changing the boundaries of natural zones