Sverdrup Island, in the Kara Sea, is currently occupied by polar desert vegetation. The analysis of Alleröd deposits indicates a climate drier than presently, with increased summer and decreased winter temperatures. The relative scarcity of distal pollen indicates that mainland source areas were located further south than at present. Younger Dryas cooling and increased dryness resulted in an increase of the proportions of Artemisia, Chenopodiaceae and Salix pollen, and in the extent of Sphagnum mosses. Preboreal time was marked by warmer, more humid conditions, with dwarf birches, Ericales and possibly Alnus fruticosa. The increased proportions of distally-derived arboreal birch pollen, coupled with the local component of the assemblages, indicates that the early Holocene represented the climatic optimum, initiated by the opening of the Arctic Ocean. Subsequent climate fluctuations were muted on Sverdrup Island, due to the development of microclimatic conditions associated with an oceanic regime. © 1997 INQUA/Elsevier Science Ltd.