Norfolk Naval Shipyard in Virginia is an essential maintenance facility for the nation's fleet of nuclear-powered submarines and aircraft carriers. And it's facing an existential threat. Rising seas will likely engulf the shipyard by century's end, but the reckoning could come much sooner. It's "going to disappear" unless the Pentagon acts quickly to protect it, said Ray Mabus, Navy secretary under President Barack Obama. InsideClimate News animates the risk in this video.