The data on nuclear contamination sources for terrestrial and marine environment of the Russian Arctic have been summarized since the Cold War time. Having been stored and deposited in the area without any treatment for a long time, they gradually transformed into accumulated environmental damage for nature and human population of the North. They should be treated as a great danger for the nearest future, especially those of underwater storage. For the first time the relevant data on accumulated environmental harm in Greenland is involved into research by Russian investigators. The political situation in Russia and Greenland is compared. An urgent need for nuclear contaminations’ simultaneous development in the Circumpolar Arctic has been proven. Recent Russian advances in nuclear contaminations management could start an extensive international program in this field.