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Study: Tropical cyclones migrating out of tropics



WASHINGTON (AP) - Tropical cyclones worldwide are moving out of the tropics and more toward the poles and generally larger populations, likely because of global warming, a surprising new study finds. Atlantic hurricanes, however, don't follow this trend.

While other studies have looked at the strength and frequency of the storms, which are called hurricanes in North America, this is the first study that looks at where they are geographically when they peak. It found in the last 30 years, tropical cyclones, regardless of their size, are peaking 33 miles farther north each decade in the Northern Hemisphere and 38 miles farther south each decade in the Southern Hemisphere.

That means about 100 miles toward the more populous mid-latitudes since 1982, the starting date for the study released Wednesday by the journal Nature.

"The storms en masse are migrating out of the tropics," said study lead author James Kossin of the National Climatic Data Center and the University of Wisconsin. Kossin used historical tracks of storms in the Western Pacific, Eastern Pacific, North Indian Ocean, South Indian Ocean, South Pacific and the Atlantic.

That means more people at risk, especially in the Northern Hemisphere, because "you're going to hit more population areas," said Yale University historian and cartographer Bill Rankin, who wasn't part of the study.

The trend, however, is not statistically significant in the Atlantic basin, where storms threaten the U.S. East Coast. In the Atlantic region, the study has seen a northward drift of storms of only 4 miles a decade, which just could be random.

Kossin said the Atlantic region is different because of changes in pollution over the United States and other factors.

Kossin and colleagues say the changes start with man-made global warming, which alters air circulation from the tropics to just farther north and south. In the tropics, those changes increase upper atmosphere wind shifts called shear that weaken cyclone development. At higher latitudes the changes decrease the storm-decapitating shear, making those areas more favorable for storm intensification.

"The tropics are becoming less hospitable" for these storms, Kossin said. "The higher latitudes are becoming less hostile."

Past storm studies have been criticized because data doesn't go back many years. But Kossin, his colleagues and outside scientists say by looking at where geographically storms hit their peak this study avoids problems with haphazard measurements and thus can make a stronger connection to climate change.

"This is an important, very well researched paper that uncovers something that was unknown previously," said hurricane researcher Chris Landsea, science officer at the National Hurricane Center. Florida International University hurricane professor Hugh Willoughby called this the strongest tropical cyclone and global warming link yet.

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hyoung3595 May 14 2014 at 6:39 PM

No body deserves to be hit by twisters. But for the life of me, I cant understand why they rebuild in the same area. Knowwing its coming again.

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1 reply
paddleman1928 hyoung3595 May 14 2014 at 7:18 PM

because somebody-other than themselves-always foots the bill

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testakel May 14 2014 at 8:30 PM

Who cares weather global warming is real are not. People who believe in it do very little about it. Well people who have reason for it not to be real spend millions of dollars and even have created there own news channel to attach the word (liberal) to any meanful science to support it's existence. Therefore the logical outcome will be the grandchildren of one side will get to say my grandpa was right as weather conditions make there life unbearable or doesn't.

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lynnlale May 14 2014 at 8:57 PM

When will all of this foolishness end .....EVERYTHING is gobal warming ....

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maxcranium May 14 2014 at 9:01 PM

The Native Americans have a rain dance that worked.
But we stopped them from their culture. Now look?!

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muzpuf May 14 2014 at 9:07 PM

yes in the 50 years they have had satellite's able to track these storms the only conclusion is global warming ....the earth is 5 billion years and with 50 years of data they have figured it out

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envoyltd May 14 2014 at 9:08 PM

Global Warming = Free cash from taxpayers

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gdmn2find May 14 2014 at 9:15 PM

Please...weather guessers are wrong most of the time. They input their data as they perceive it and in a variety of ways, which is why you will see like a spaghetti of a half dozen colors for each proposed track when they do their forecasts. They just can't say exactly which one is correct. They have a worse "batting average" than the worst MLB player and still retain their jobs. So don't make outrageous claims about climate change, global warming, nuclear winters and so on, when you can't get the weather right in the same 24 hour period. Especially if you live in the Washington DC, MD,VA area. They are the absolute worst for forecasts. Along with the predictions for hurricanes. Again computers. Garbage in? Garbage out.

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robewil1 May 14 2014 at 9:33 PM

total B.S.

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heh1111 May 14 2014 at 9:35 PM

with the overwhelming amount of evidence provided from the smartest climate scientists on the planet, people are starting to pay attention, teabaggers who are told by their corprate one percent gods not to believe global warming is real because it interupts the billions in profit they send directly to offshore banks to avoid paying us taxes are exempt from reality

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4 replies
dan_crabtree May 14 2014 at 9:50 PM

chances are it won't be in the tropics....or in plain english.. they have no real idea....could might.. maybe...and possibly are all key words in the liberal crowd of idiots..

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