There are several possible reasons why the jet streams are moving, the authors note.
"It could be part of a natural cycle. Or [it's] just a random fluctuation and we happened to pick a time of random fluctuation," Caldeira said.
"Or it could be caused by global warming."
Kerry Emanuel, a meteorologist at the Massachusetts Institute of Technology in Cambridge, was not involved in the study.
Emanuel said the analysis and results of the new research seem reasonable.
"My guess is that the most important effect on hurricanes would be on their paths. The shift could mean that more hurricanes make landfall along the U.S. East Coast and Gulf Coast."
But Emanuel also noted that an April 2007 study based on computer simulations theorized that wind shear is increasing, and that could cut down on hurricane formation.
Global Warming Debate
The new research could add to the debate about whether global warming is having an effect on hurricane formation.
(Related: "Hurricanes to Be Sapped, Not Strengthened, by Warming?" [April 18, 2007].)
Keith Blackwell, a meteorologist at the University of South Alabama's Coastal Weather Research Center in Mobile, was also not involved in the study.
"The planet appears to be warming, but I think the jury is still out on the cause," Blackwell said.
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