Sea ice in Arctic shrinks to second lowest level on record. Could be ice free by 2030…. There is no going back, and won’t be for eons, perhaps until the next Ice Age. Incredibly profound change. The arctic will be open to navigation in the summer months before we know it. You’ll be able to go from the Chicago in the middle of North America to Novosibersk the center of Asia entirely by water. Hell, there might be “adventure cruises” doing just that within a decade or two. I think the melting of the Arctic will not only be environmentally and climatically profound, but it permanently alters geopolitics and even the way we view the world on an east-west axis, because the quickest way between Asia and America will no longer be via the Pacific. While we can barely get our heads around any of this, kids born today will have trouble believing that people used to walk on the North Pole. Global warming has happened so much faster than we thought it would.