In the recently published article by Kossin et al. (Nature, 2014, dx.doi.org/10.1038/nature13278), they show that there is a trend toward poleward migration of the location of tropical cyclone (hurricanes and typhoons) maximum intensity in most areas of the world.
Their proposed explanation focuses on the tropical expansion (the increasing area of the world where tropical phenomena is observed has expanded in time). Is there some alternative explanation for the poleward migration of the hurricanes?
The shift seems to be occurring in the Pacific and Indian Oceans but not in the Atlantic. How can we explain that difference?