Likewise the albedo thing doesn't seem the major issue; the poles are very cloudy anyway.

I expect the real positive feedback is in the changing ratio of surface area to mass of the ice as it melts. Surface area decreases with the square, mass with the cube (pardon!), so the less ice, the faster it retreats. I suppose this is why we're seeing so much greater warming at the poles.

I suppose then the problem is the loss of heat sink. The phase change of melting ice soaks up a lot of heat. As the ice shrinks that sink goes away.

To dramatize this my old physics teacher would set a paper cup full of water on top of a bunsen burner. The cup sits there happily ignoring the blue flame underneath it right up to the point that the last of its contents is gone. Then it ignites.

So we may expect that more equatorial regions of the globe won't experience the full effect of warming until the polar ice is gone. At which point ... well, I'm too busy moving to Tasmania to think about it.