ИСТИНА

Coasts of the Kara Sea retreat at a mean annual rate of 0.7 m/yr. At the Kharasavey gas condensate field in Western Yamal the development takes place from the 1970s and archival aerial photographs are available for 1977 and 1988 yrs. Together with multitemporal satellite imagery (1964, 2006, 2016), this allows us to trace in detail the temporal variability of permafrost coasts’ destruction rates. Field data on the coastal sediments composition and ice content made it possible to clarify the reasons for the high rates of coastal segments retreat in certain periods. At 9-km section coastal cliffs of 7-12 m height retreat at a mean rate of 1.1 m/yr during 52-year period, while on certain segments it reaches 2-3 m/yr. For icy coasts, acceleration of destruction rates in warm periods is noted, while increased rates of retreat of segments with low ice content often indicate an anthropogenic pressure (sediment excavation from beach and coastal bluff, dredging in the nearshore zone, etc.).