ИСТИНА

Massive ice beds are ice layers in permafrost one to tens of meters in thickness, contributing to the development of retrogressive thaw slumps in the coastal zone. They are common for part of the Arctic coastal lowlands; in Russia, the main region of their distribution (north of Western Siberia) coincides with the region of oil and gas fields exploration and development. The data on the distribution of massive ice beds were compared with the data on the coastal retreat rates collected in the database of the Arctic Coastal Dynamics project and in the Atlas of Abrasion and Ice-Gouging Hazards of the Coastal Shelf Zone of the Seas of the Russian Arctic (Version 12.2020). On a regional scale, no direct relationship was found between the presence of massive ice beds and the mean annual rates of coastal retreat, since other factors smooth out the effect of accelerated erosion caused by massive ice degradation. However, for specific coastal segments and on a short time scale, presence of massive ice beds leads to a significant (2 times or more) increase in the rate of coastal erosion. The role of thermodenudation (permafrost melting) increases in warmer years. At the same time, in one of the considered key areas, land development had a greater impact on the retreat rate than the presence of massive ice beds or an increase in air temperatures.