A continuous record of paleogeographic events in the Shantar islands since the end of the Pleistocene has been obtained by a multy-proxy study of the stratigraphy of the blanket peatland. The biostratigraphical studies included botanical, diatom, and pollen analyses. The age-depth model has been developed using seven radiocarbon dates. Data on the development of the environment have been obtained for the first time in the coldest part of the Sea of Okhotsk. The paleoclimatic events were synchronous and metachronous with the regional data and the global changes. The Younger Dryas was much colder in the Shantar islands than in other areas around the Sea of Okhotsk. The climate became more marine after isolation of the islands in the early–middle Holocene. The cold sea and the drifting ice were among the major factors that resulted in the poorly defined early and middle Holocene optimums in this area and in the characteristics of the climatic rhythm. Models have been proposed to explain the alternation of relatively warm and cold periods with different humidity. The age of periods of heavy snowfall, as shown by changes in the role of dwarf pine in the island vegetation, has been estimated. The local swamp and zonal landscape phases have been highlighted. Spruce appeared in this area ~11 410–10 345 cal yr BP, when a landbridge existed; spruce trees became common in the middle Holocene, especially at the turn of the middle–late Holocene. The thermokarst processes were one of the controlling factors of swamp landscapes. The environment underwent major changes in the Little Ice Age; the most severe conditions occurred ~500–260 cal yr BP. In the most-recent 210 years, the most considerable changes in landscapes were related to fires of a human origin.

Allochthonous biofossil distribution in the blanket peat bog of Bolshoy Shantar Island was used to analyze atmospheric circulation anomalies in the north-western Okhotsk Sea over the last 12.6 ka. The main aim of this study was to determine periods of intensification of deep cyclones and extreme storms. The composition of bioaerosols is significantly influenced by atmospheric zonal and meridional transport anomalies associated with anomalies of the monsoon system of Northeast Asia, atmospheric fronts and cyclone trajectories. Marine diatoms enter the peatland from the sea during extreme storms and record the passage of sea cyclones in the autumn-winter, whereas the distribution of allochthonous pollen indicates the intensity of continental cyclones. We used Pinus pumila pollen as an indicator of heavy snowfalls and winter cyclone activity. Fifteen phases of extreme storms were identified. Changes in ice coverage also played an important role in bioaerosol emission. During cold periods, emissions of bioaerosols mainly occurred in the open sea, whereas during warm periods, emissions occurred near the coast. The recurrence and intensity of cyclones during the cold seasons depends on displacement of the Siberian High and Aleutian Low. Periods of continental cyclones intensified in spring-summer and coincided with periods of active winter cyclogenesis.

The article analyzes manifestations of the Little Ice Age in the southern mainland Russian Far East. The study is based on a synthesis of paleogeographic data, which, in the absence of historical records, are the most informative source for reconstructing environmental changes. The primary natural archives are deposits of mountain lakes and peatlands situated across different landscape belts of the low- to mid-elevation zones of the Sikhote-Alin and East Manchurian Mountains (at elevations of 300 to 1600 m). Changes in the composition of diatom flora, as well as components of forest and peatland ecosystems, provide the data to reconstruct abrupt climate shifts that took place from the 12th–13th centuries onward, including the transition from the Medieval Climate Anomaly. It is established that the late medieval cooling in the southern Russian Far East was wet, characterized by increased precipitation, including winter snowfall, and frequent flash floods. This baseline was punctuated by short-term intervals of reduced moisture availability and seasonal droughts. These drier conditions typically coincided with solar activity minima. The cooling affected the development of mountain landscapes, resulting in a change in the ratio of canopy-forming species, a shift in landscape belt boundaries, widespread development of sphagnum peatlands, and the emergence of northern species among peat-forming flora. At the end of the Little Ice Age, human settlement and active land use became the primary drivers of landscape transformation.