The Arctic just hit an unfortunate climate milestone

The last nine years have been the warmest ever recorded in the Arctic Circle, and this year saw a number of new milestones in the region: It was the rainiest summer on record, and plant life bloomed across the tundra at a near-record pace. 

As the Arctic reacts to the planet-warming gasses that humans have pumped into the atmosphere, the region is swiftly transforming and entering what scientists call a “new regime.” That’s one of the findings of this year’s Arctic Report Card, a document...