Actually, it is quite alarming if the Arctic is turning green. That itself is sensationalist. One of the primary ways our planet cools itself is by reflecting heat back into space. A white arctic is very efficient at reflecting heat. Green is not so good at that.

In terms of shifting biomes -- there used to be alligators that lived in the arctic. We seem determined to make that possible again. Such a world would be drastically different than the one we live in now. Such possibilities are indeed alarming.