Permafrost landscapes are particularly susceptible to the observed climate change due to the presence of ice in the ground. This paper presents the results of the mapping and assessment of landscapes and their vulnerability to potential human impact and further climate change in the remote region of Eastern Chukotka. The combination of field studies and remote sensing data analysis allowed us to identify the distribution of landscapes within the study polygon, reveal the factors determining their stability, and classify them by vulnerability to the external impacts using a hazard index, H. In total, 33 landscapes characterized by unique combinations of vegetation cover, soil type, relief, and ground composition were detected within the 172 km(2) study polygon. The most stable landscapes of the study polygon occupy 31.7% of the polygon area; they are the slopes and tops of mountains covered with stony-lichen tundra, alpine meadows, and the leveled summit areas of the fourth glacial-marine terrace. The most unstable areas cover 19.2% of the study area and are represented by depressions, drainage hollows, waterlogged areas, and places of caterpillar vehicle passage within the terraces and water-glacial plain. The methods of assessment and mapping of the landscape vulnerability presented in this study are quite flexible and can be adapted to other permafrost regions.

Under the influence of perennial dynamics of soil thawing depth, the upper layer of permafrost periodically thaws and becomes a part of the soil profile in the permafrost zone. In this case, the horizon, which is either frozen or thawed and has a thickness of several tens of centimeters, displays an elevated ice content (moisture). This horizon between the lower boundary of the active layer and the permafrost is named a protective layer or a transient permafrost layer and functions as a buffer that hinders thawing of the ice complex with its high ice content. The study of moisture using soil-regime methods and budget calculations showed that the protective layer of permafrost in sandy and loamy soils (at the depth of 1.5-5 m) contains from 25 to 60 mm (on average, 30 mm) of water in each 10-cm-thick layer of frozen soils under different types of forests in Central Yakutia. An increase in the seasonal thawing depth of permafrost-affected soils under conditions of global climate warming and anthropogenic impacts (forest fires, destruction of forest cover, etc.) causes degradation of the protective layer. The purpose of this article is to show the effect of increasing seasonal thawing depth of permafrost-affected soils on changes in the water content and water budget in permafrost areas because of the release of moisture stored in the protective layer in the context of global climate change. It was found that with an increase in the seasonal thawing depth, the protective layer should release a significant amount of water preserved in permafrost, which may change the water budget of permafrost territories. As calculations show, with an increase in the soil seasonal thawing depth by 20-30 cm on the interfluve areas, the volume of water entering the basins of nearby thermokarst depressions (alases) and rivers from frozen soils may reach 60000-90000 m(3)/km(2). The obtained results can be used in modeling and predicting the dynamics of permafrost environments under the global climate change.