Arctic greening

We have long been hearing that the arctic is melting, but now there are headlines that it's greening as well. How far can arctic greening go, and what will the climate consequences by?

The more chlorophyll grows where it previously didn't, the more carbon gets sequestered there. If this process snowballs (yes, it's an ironic pun), then the large amounts of CO2 moving toward the poles away from the desertifying middle latitudes could leave those dryer, hotter regions emitting large amounts of heat away from the planet at night, which could cause cooling.

If such cooling occurs due to more infrared energy loss in the middle-latitudes, however, while the poles are greening; what happens? Do the growing conditions in the borreal forests improve as poles warm and middle latitudes cool, or so they get worse because forests thrive in seasonal fluctuations between warm, humid air pushing toward the poles followed by sharp cooling and freezing that protects the plants and animals enshrouded in frost and snow?

What are your predictions for how this arctic greening will play out in the long run? Will it continue and progress or self-correct? Will thick forests grow in the seas and on land or will there just be continuing greening in the form of simple algae, etc.?