We investigated the clonal diversity, genet size structure and genet longevity in populations of four arctic-alpine plants (Carex curvula, Dryas octopetala, Salix herbacea and Vaccinium uliginosum) in order to evaluate their persistence under past climatic oscillations and their potential resistance to future climate change. The size and number of genets was determined with molecular markers (AFLP) using a standardized sampling design in several homogenous climax populations across arctic-alpine regions in Europe. Genet age was estimated by dividing its size by the annual horizontal size increment from in situ growth measurements. Clonal diversity differed among species, but was generally high with a strongly left-skewed frequency distribution of genet size. The largest Carex curvula genet had an estimated minimum age of ca. 4100 years and an estimated maximum age of ca. 5000 years, while 84.8 % of the genets in this species were less than 200 years old. The oldest genets of Dryas octopetala, Salix herbacea and Vaccinium uliginosum were found to be at least 500, 450, and 1400 years old, respectively. These results indicate that individuals in the studied populations have survived pronounced climatic oscillations in the past including the Little Ice Age and post-industrial warming. The presence of genets in all size classes and the dominance of presumably young individuals suggest continuous recruitment over time, a precondition for adaptation to changing environmental conditions. Together, persistence and continuous genet turnover may ensure maximum ecosystem resilience. Thus, our results suggest that long-lived clonal plants in arctic-alpine ecosystems will persist despite considerable climatic change.