The melting of the permafrost is highly likely but the article misses the likely mechanism for this change. If the Arctic ice melts and the radiation of the sun is absorbed instead of being reflected, the Arctic could well become a zone of rising rather than falling air. The three cell circulation system of the northern hemisphere would then become either a 2 or a 4 cell system. If a two cell system results, the join between the two cells would occur at about 45 degrees north. This will result in air flowing along the surface of the earth from this latitude toward the poles. (At present, it flows from the poles southward). This will transfer massive amounts of heat northward, melting the permafrost and keeping the Arctic sea open. Of course such a change will also shift the Wheat belt and all the other vegetation belts of the Northern Hemisphere. If, as is expected, the floor of the Arctic ocean is paved with clathrates, the rise in sea temperature will result in a massive evolution of methane with the resulting scrubbing out of the oxygen from the water. Result - an anaerobic Arctic ocean with more methane evolution plus ammonia and oxides of sulphur.