This study describes detailed partitioning of phytomass carbon (C) and soil organic carbon (SOC) for four study areas in discontinuous permafrost terrain, Northeast European Russia. The mean aboveground phytomass C storage is 0.7 kg C m−2. Estimated landscape SOC storage in the four areas varies between 34.5 and 47.0 kg C m−2 with LCC (land cover classification) upscaling and 32.5–49.0 kg C m−2 with soil map upscaling. A nested upscaling approach using a Landsat thematic mapper land cover classification for the surrounding region provides estimates within 5 ± 5% of the local high‐resolution estimates. Permafrost peat plateaus hold the majority of total and frozen SOC, especially in the more southern study areas. Burying of SOC through cryoturbation of O‐ or A‐horizons contributes between 1% and 16% (mean 5%) of total landscape SOC. The effect of active layer deepening and thermokarst expansion on SOC remobilization is modeled for one of the four areas. The active layer thickness dynamics from 1980 to 2099 is modeled using a transient spatially distributed permafrost model and lateral expansion of peat plateau thermokarst lakes is simulated using geographic information system analyses. Active layer deepening is expected to increase the proportion of SOC affected by seasonal thawing from 29% to 58%. A lateral expansion of 30 m would increase the amount of SOC stored in thermokarst lakes/fens from 2% to 22% of all SOC. By the end of this century, active layer deepening will likely affect more SOC than thermokarst expansion, but the SOC stores vulnerable to thermokarst are less decomposed.

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Long‐term (1982–1995) observations of the ground thermal regime of a drained thaw‐lake basin in the Pechora Lowlands of the Russian European north revealed a high spatial and temporal variability in the ground temperature response to artificial drainage. The thermal response was controlled by the atmospheric climate and by evolution of the landsurface following drainage. Observed changes in permafrost conditions were related to three climatic subperiods identified from air and ground temperature trends. The first (1982–1984) was characterized by gradual ground cooling associated with partial formation of permafrost patches under the initial stage of formation of marshy meadows. The second (1985–1987) involved strong ground cooling, resulting in the formation of a subsurface permafrost layer beneath most of the basin. The third (1988–1995) was marked by a gradual increase in annual mean ground temperature, promoting partial permafrost degradation under marshy meadows and willow stands. Initially, newly aggraded permafrost remained under peat mounds and tundra meadows. The spatial pattern of permafrost change can be attributed to heterogeneous landsurface evolution and variable snow thickness. Four distinct ground temperature regimes are distinguished: (i) thawed ground, (ii) deep permafrost, (iii) unstable permafrost and (iv) stable permafrost.