New York Times: JUST a quarter-century ago, and for millenniums before that, the Arctic Ocean was covered year-round by ice, creating an impregnable wilderness that humans rarely negotiated. Today, as the effects of global warming are amplified in the high north, most of the ocean is open water during the summer and covered by ice only in the winter. This unexpected transformation has radically altered the stakes for the Arctic, especially for the eight nations and indigenous peoples that surround it. But while...