Daily Green: The only question on September’s plate, when it comes to climate milestones, is whether the Arctic will settle for the second-greatest melt in history, or go ahead and overtake 2008 as the meltiest year on record. Already, loss of sea ice has exceeded the extreme seen in 2005, which at the time was seen as a shocking sign of global warming. That record fell in 2007, by a long stretch. While melting has leveled off somewhat in the last week, there’s still a chance that this summer’s …