Colin P said:
Russia has the right and obligation to secure their Arctic region and manage vessel and air movements there. It's where their jurisdiction butts up against others is where potential aggression and friction appear.
They're also paranoid, mainly about Chinese expansion it seems:
China, Russia, and Arctic Geopolitics
China’s burgeoning role in the Arctic could translate into direct competition with Russia.
Russia’s involvement in the region is to be expected, as one of the eight countries with territory above the Arctic Circle — and vast territory at that, with thousands of miles of coastline. Moscow’s involvement has been significant and long-lasting, with Russia advocating for the development of the Northern Sea Route along its Siberian coast as an alternative to southern routes through the Suez Canal and investing in the construction of the only icebreakers capable of operating in the Arctic Ocean.
China is a less obvious player in the Arctic, with its closest territory some 5,000 miles by sea from the Bering Strait. Even so, China has in recent years pressed for a greater role in Arctic affairs, becoming one of the 13 observer states of the Arctic Council in 2013. In 2018, China released an official white paper entitled “China’s Arctic Policy” — a step that in and of itself signals the country’s intent to play a larger role in the region — in which it outlines its priorities in the Arctic and describes itself as a “near-Arctic state.”
The cooperation between China and Russia in recent years adds an intriguing complexity to Arctic geopolitics. Experts are divided on whether the warming of Sino-Russian relations is a true strategic alliance or merely a marriage of convenience. Proponents of the former point to the numerous agreements signed between the two countries — punctuated by the personal friendship of the two nations’ leaders — and the two sides’ common voting record on the United Nations Security Council. Skeptics reason that Russia and China often have diverging goals despite mutual interests and remain distrustful of each others’ intentions. In this paper, we focus on the long-term outlook for the Sino-Russian relationship regarding the Arctic.
https://thediplomat.com/2020/03/china-russia-and-arctic-geopolitics/