An unprecedented Russian military buildup in the Arctic includes a “superweapon” Poseidon 2M39 torpedo being tested on the seabed, CNN reports. The buildup and testing is thanks to ice-free waters created by climate change in an area that is normally frozen. Weapons experts told CNN that testing of the nuclear-powered Poseidon torpedo is especially worrying because it is designed to evade American coastal defense mechanisms by skirting the seabed floor. CNN reports the device is designed to deliver a warhead of multiple megatons, causing radioactive waves that would “render swaths of the target coastline uninhabitable for decades.” A senior State Department official told CNN, “There's clearly a military challenge from the Russians in the Arctic,” that includes repurposing old Cold War bases and building new facilities. “That has implications for the United States and its allies, not least because it creates the capacity to project power up to the North Atlantic.”