Well, you've melted the Arctic ice in so far as it impedes navigation of the Northern Passage so you now have an all-year-round easy route from Murmansk to the Bering Sea. In OTL this could be done in Summer with help, as with some Nazi raiders escorted through during the NazI-Soviet Pact, but now it is permanent. That also means that towns at the mouths of the Ob and Yenisei rivers can support much larger populations and will quickly grow into sizeable cities. In fact, Russia will view its Northern coast as the one vital coast, giving access as it does to settlement and exploitation of Siberia