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Global warming may spur wind shear, sap hurricanes
Tue Apr 17, 2007 6:32 PM ET

By Jim Loney

MIAMI (Reuters) - Global warming could increase a climate phenomenon known as wind shear that inhibits Atlantic hurricanes, a potentially positive result of climate change, according to new research released on Tuesday.

The study, to be published on Wednesday in Geophysical Research Letters, found that climate model simulations show a "robust increase" in wind shear in the tropical Atlantic during the 21st century from global warming.

Wind shear, a difference in wind speed or direction at different altitudes, tends to tear apart tropical cyclones, preventing nascent ones from growing and already-formed hurricanes from becoming the monster storms that cause the most damage.

The effect of global warming on wind shear is similar to the impact of El Nino, the periodic eastern Pacific warm-water phenomenon that tends to put a damper on Atlantic storms. The sudden development of El Nino was credited for an unexpectedly mild Atlantic season last year, when only 10 storms formed.

Debate on the likelihood that human-generated climate change contributes to hurricane development has raged since the 2005 Atlantic season, which produced a record-shattering 28 tropical storms and hurricanes.

That season saw some of the most powerful hurricanes in history and produced Katrina, which killed 1,500 people and caused $80 billion damage on the U.S. Gulf Coast. The hurricane threat roiled global oil and gas markets.

HEATING UP SEA WATER

In recent years some scientists have suggested that human-induced greenhouse warming may be increasing the intensity of Atlantic hurricanes by heating up the sea water from which they draw their energy.

In February a report by the Intergovernmental Panel on Climate Change said it was "more likely than not" that humans contribute to a trend of increasingly intense hurricanes.

But researchers in the new study said increased wind shear could counter the effect of warming waters in the Atlantic.

"The environmental changes found in the study do not suggest a big increase in tropical Atlantic hurricane activity during the 21st century," said Brian Soden, a co-author of the report.

The increase in wind shear was only seen in the Atlantic and eastern Pacific. In the western Pacific, global warming appeared to cause both increased water temperatures and a reduction in wind shear, Soden said.

The study, by scientists at the University of Miami's Rosenstiel School and a National Oceanic and Atmospheric Administration lab in Princeton, New Jersey, is the first to identify changes in wind shear that could counteract the other impacts of global warming on hurricanes, the researchers said.

Soden said as the climate warms, atmospheric circulation tends to weaken and upper level westerlies shift further eastward into the Atlantic, increasing wind shear there. The effect is similar to an El Nino impact.

"The difference is that El Nino is a natural cycle, whereas the results from global warming are much smaller year-to-year but they accumulate over time," he said.

Hurricane researchers believe the Atlantic-Caribbean hurricane zone is in a period of heightened activity that began around 1995 and could last between 25 and 40 years.
Waaaaaaaaay over my head but glad smarter people than I are looking into it. Thanks Marty. smile
Of course, that is assuming that "global warming" is real, as severe as they say it is, and continues at the rate they say it will. "They" happen to get paid a lot of money to hype up this issue.
Hoax of the Century - Global Warming! Every event: tornadoes,severe thunderstorms,rise or fall in water temps. unusual bird migrations,bleached coral, dead sea turtles,coconut palm blight and every other happenstance out of "norm" appears,could, might, maybe, might be,could be, possibly,perchance, perhaps - global warming. JMO.
(Attack dog release time)

The wind shear Westerlies were the causation of a non-hurricane season last year, hopefully those climatic conditions will take place again this season. June 1,not far off.
Posted By: Anonymous Re: Global warming may spur wind shear, sap hurricanes - 04/29/07 06:39 AM
Britain has just had the warmest April since records began several hundred years ago (so possibly for some time before that). Following an exceptionally warm (and dry) winter. I don't think there's much doubt that SOMETHING is happening - it's just the cause and implications that people seem to struggle with. It may well be an extension of pre-existing natural cycles, perhaps related to sun activity, perhaps not. I don't see that the cause matters - what DOES matter is that rainfall patterns also seem to be changing, meaning that areas previously arable may become semi-desert and unable to produce food, while other areas that experience greater rainfall won't be able to produce food because we won't have exploited the new rain. Unless we accept what's happening and do something about it, not trying to stop it (futile) but working out how to deal with it, we are headed for a catastrophe.

As a separate question we have POSSIBLY rising sea levels that MAY render vast areas of coastal lands (and many river valleys) uninhabitable. Not too good for Louisiana or eastern Britain and NW Europe, but catastrophic for Bangladesh, the Maldives and many other places. Including AC. Sea levels in at least some areas ARE rising - the Thames barrier east of London which protects the capital from surges up the estuary is already becoming marginal, and there are plans for a second much more extensive one further out which is itself expected to have a limited life. And there is official policy not to protect large areas of eastern England from the inundation which is now accepted as inevitable.

We don't know the cause or the timescale, nor necessarily all the effects. So we don't know if we are looking at changes over several generations or something much more rapid. But pretending nothing is happening is absurd. It seems likely that people already born will see dramatic changes in their lifetimes.
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