Nowhere on earth is global warming proceeding more rapidly than inside the Arctic Circle. Over the past two decades, the Arctic has grown five degrees Celsius warmer. And the trend is accelerating, with the Arctic warming nearly four times as rapidly as the rest of the planet.Climate scientists expect that Arctic median temperatures will rise as much as 2 degrees Celsius annually over the coming decade.Although temperatures normally change with glacial speed, in the Arctic those transformations are now noticeable to the naked eye: Last year marked a...