Powerful and Dangerous Hurricanes Peak Further North Than in the Past

Powerful and dangerous storms are peaking further north and south than in the past. It turns out that hurricanes have been migrating away from the tropics and further afield in recent decades, hinting that climate change may be affecting weather systems.

In order to trace where hurricanes and typhoons have been traveling in recent years, the researchers used international data from 1982 to 2012. They then marked the peak intensity of each of the storms in order to see whether the hurricanes were traveling further afield.

"The absolute value of the latitudes at which these storms reach their maximum intensity seems to be increasing over time, in most places," said Kerry Emanuel, one of the researchers, in a news release. "The trend is statistically significant at a pretty high level."

In fact, the researchers found that over the last 30 years, these tropical storms are moving toward the poles at a rate of about 33 miles per decade in the Northern Hemisphere and 38 miles per decade in the Southern Hemisphere. While there are certainly region differences in the poleward movement of these storms, the fact that every ocean basin besides the Indian Ocean has experienced these changes points to the fact that this particular phenomenon is global.

"We think, but have not yet been able to establish, that this is connected to independently observed poleward expansion of the Hadley circulation," said Emanuel in a news release, referring to the large-scale pattern of global winds.

In recent years, the Hadley circulation has moved further poleward. This has caused wind shear, which inhibits cyclone formation, to increase in the tropics and decrease in the poles. This means that it's more difficult to form cyclones, which means that their incidence has diminished. However, their intensity may be increasing.

The findings are published in the journal Nature.