U can tell Hurricane season is around the corner

[AussieMark]

just skimming thru yahoo news sections like I do daily I found a few articles on it today and linking to global warming


Scientists say warming threatening Fla.

TALLAHASSEE, Fla. - Florida's governor cautiously entered the debate Wednesday over whether rising global temperatures are to blame for an increase in the number of strong hurricanes, meeting with two researchers who say global warming is threatening Florida with a long-term future of more bad storms.

Bush met with Peter Webster and Judith Curry of the Georgia Institute of Technology, who published research last year showing an increase in global hurricane intensity, with a doubling of the number of Category 4 or 5 hurricanes since 1970. That increase coincides with a rise of nearly 1 degree Fahrenheit in ocean surface temperatures, they say.

While they agree with other scientists that the Atlantic basin is in a natural cyclical increase in hurricanes, they argue that can't explain by itself such a dramatic increase in strong storms. Warmer temperatures globally mean warmer water, which is what fuels hurricanes.

"It's very complex, but there's one thing that we do know: if you increase these surface temperatures you're going to get more intense hurricanes," said Curry. "I think we can say — it's not totally conclusive, but with considerable confidence — that there is this connection between global warming and increased global hurricane intensity and the increased number of hurricanes in the north Atlantic."

There isn't scientific consensus that global temperature increases explain increased hurricane intensity, and there are some researchers who say there isn't a continuing long-term pattern of global warming at all.

The debate is something of a storm itself, and Bush joined it cautiously.

"He said they presented some pretty compelling information," said Bush spokesman Russell Schweiss, declining to say whether Bush agrees that global warming is increasing the number of strong hurricanes. "He encouraged them to continue with their research."

Webster and Curry's meeting came as environmentalists seek to push to the state level efforts to curb the emission of so-called greenhouse gasses that are blamed for causing global temperature increases.

They say President Bush's administration in Washington hasn't done enough to combat greenhouse gas emissions — and note that Florida could help by cutting emissions since it's the fifth largest producer of such gasses in the United States.

Besides, in hurricane alley, Florida has more to gain from lower emissions than the country as a whole if Webster and Curry's findings are right , said Jerry Karnas of the Florida Wildlife Federation, which set up the meeting.

Bush didn't commit to any policy changes in the meeting.

But Attorney General Charlie Crist, with whom the scientists also met, said he was impressed. Crist is one of several men running to be the next governor.

"It's fairly apparent that (global warming) has increased (hurricane) activity," Crist said after meeting the scientists.

Webster and Curry's research, published last year in the journal Science along with another 2005 study in the journal Nature by Massachusetts Institute of Technology climatologist Kerry Emanuel appeared coincidentally about the time the country was looking at pictures of the devastation from Hurricane Katrina.

But there are those who say the connection between warming and hurricanes isn't so clear.

Florida's state climatologist James O'Brien is one, arguing that the increase in stronger storms is part of a natural cycle.

"The jury is still out whether they're right - or I'm right," said O'Brien, who is director of the Florida State Center for Ocean-Atmospheric Prediction Studies.

O'Brien said there's no question that some parts of the ocean are heating up — at the poles for example — but that tropical waters don't seem to be.

Other skeptics of the global warming impact on hurricanes are probably the nation's best-known hurricane predictors — Colorado State University's William Gray and Max Mayfield of the National Hurricane Center.

In a recent Washington Post article, Gray, whose hurricane forecast is widely disseminated, proclaimed the whole idea of global warming "one of the greatest hoaxes ever perpetrated on the American people." He has said the Earth is getting warmer — but that it will soon begin cooling because of natural weather cycles.

Mayfield, director of the hurricane center's Tropical Prediction Center in Miami, doesn't deny that temperatures are going up, but said last year that's not to blame for more storms.

"The increased activity since 1995 is due to natural fluctuations — cycles of hurricane activity ... not enhanced substantially by global warming," Mayfield told a congressional panel.

But Webster said the patterns are going beyond the natural variation.

"Anybody who doesn't put into their risk analysis the possibility of increasing hurricanes in the Southeast, in the Gulf states, is probably a little irresponsible," Webster said.

"Even if there's only an 80 percent that we're right," Curry added, "it's a serious risk."

[AussieMark]

Climate change could fuel fiercer hurricane cycles

WASHINGTON (AFP) - Human-induced climate change could be fueling increasingly active and deadly hurricane cycles, US researchers said, a day ahead of the official Atlantic hurricane season's start on Thursday.

"Anthropogenic factors are likely responsible for long-term trends in tropical Atlantic warmth and tropical cyclone activity," Penn State and Massachusetts Institute of Technology (MIT) researchers report in an upcoming issue of the American Geophysical Societys EOS.

Researchers Michael Mann, associate professor of meteorology and geosciences at Penn State, and Kerry Emanuel, professor of atmospheric sciences at MIT, evaluated the record of global sea surface temperatures, hurricane frequency, and aerosol impacts.

They also studied the Atlantic Multidecadal Oscillation (AMO), an ocean cycle similar, but weaker and less frequent, than the El Nino-La Nina cycle in the eastern Pacific ocean.

"Though other scientists have suggested that the AMO, a cycle of from 50-70 years, is the significant contributing factor to the increase in number and strength of hurricanes, their statistical analysis and modeling indicate that it is only the tropical Atlantic sea surface temperature that is responsible, tempered by the cooling effects of some lower atmospheric pollutants," a Penn State communique said.

"We only have a good record of hurricanes and sea surface temperature for a little more than the last 100 years," noted Mann, also director of Penn States Earth System Science Center.

"This means we have only observed about one and a half to two cycles of the AMO. Peer-reviewed research does suggest that the signal exists, but it is difficult to estimate the period and magnitude of the oscillation directly from observations," he explained.

On the other hand, Mann and Emanuel said, "There appears to be a strong historical relationship between variations in tropical Atlantic sea surface temperature and tropical cyclone activity extending back through the 19th century."

"The cause of increased tropical Atlantic sea surface temperatures is the real question," according to Penn State's statement. "One contributor must be overall global sea surface temperature trends."

"If the AMO, a regional effect, is not contributing significantly to the increase, then the increase must come from general global warming, which most researchers attribute to human actions," the statement said.

The researchers looked at the tropical Atlantic sea surface temperature record and compared it to global sea surface temperatures, finding that the two closely tracked together.

But global fluctuation did not account for everything, they said.

The Atlantic season officially starts Thursday and US experts say as many as 10 hurricanes could form in the Atlantic and four could slam ashore in the southern United States.

That could easily spell disaster for residents of coastal areas, thousands of whom have not yet finished repairing homes damaged by last year's Katrina, Rita and other massive storms.

Katrina ranked as category three on a five-point scale when it slammed ashore near New Orleans, causing the deaths of more than 1,500 people.

In all, 2005 saw a record 15 hurricanes, among an unprecedented 28 named storms that formed in the Atlantic. For the first time on record, seven of the hurricanes were considered major, meaning they hit category three or higher.

It was also the costliest hurricane season, with damage estimated at more than 100 billion dollars.

[AussieMark]

2 Studies Link Global Warming to Greater Power of Hurricanes

Climate researchers at Purdue University and the Massachusetts Institute of Technology separately reported new evidence yesterday supporting the idea that global warming is causing stronger hurricanes.

As Hurricane Season Looms, States Aim to Scare (May 31, 2006)That claim is the subject of a long-running scientific dispute. And while the new research supports one side, neither the authors nor other climate experts say it is conclusive.

In one new paper, to appear in a coming issue of Geophysical Research Letters, Matthew Huber of the Purdue department of earth and atmospheric sciences and Ryan L. Sriver, a graduate student there, calculate the total damage that could be caused by storms worldwide, using data normally applied to reconciling weather forecast models with observed weather events.

The Purdue scientists found that their results matched earlier work by Kerry A. Emanuel, a hurricane expert at M.I.T. Dr. Emanuel has argued that global warming, specifically the warming of the tropical oceans, is already increasing the power expended by hurricanes.

The approach used by the Purdue researchers, concentrating on what is called reanalysis data, has never been tried for this purpose before, Dr. Huber said in an interview, adding, "We were surprised that it did as well as it did."

In a statement accompanying the release of the study, Dr. Huber said the results were important because the overall measure of cyclone activity, whether through more intense storms or more frequent storms, had doubled with a one-quarter-degree increase in average global temperature.

In the other new study, Dr. Emanuel and Michael E. Mann, a meteorologist at Pennsylvania State University, compared records of global sea surface temperatures with those of the tropical Atlantic and said the recent strengthening of hurricanes was attributable largely to the rise in ocean surface temperature.

Some researchers say long-term cycles unrelated to global warming are the major cause of hurricane strengthening in recent decades. But Dr. Emanuel and Dr. Mann, whose work is to be published in Eos, a publication of the American Geophysical Union, maintained that the cycles, the Atlantic Multidecadal Oscillation, had little if any effect.

In fact, they reported that the most recent cooling cycle could just as well be attributed to the presence of particle pollutants in the atmosphere that block sunlight and, they said, could have temporarily counteracted some of the influence of warming from accumulating greenhouse gases. Dr. Mann said the new findings also suggested that as efforts to cut pollution by particles and aerosols continued to intensify, their cooling effects would diminish while the heating effects of greenhouse gases would remain unconstrained.

As a result, he said, "we could be in for much larger increases in Atlantic sea surface temperatures, and tropical cyclone activities, in the decades ahead." He joked that some might urge an increase in pollution, but called it "a Faustian bargain."

Stanley B. Goldenberg, a meteorologist with the Hurricane Research Division of the National Oceanic and Atmospheric Administration who has expressed skepticism about any connection between global warming and hurricane intensity, said he had not seen the new papers but had read nothing in other recent research to change his view.

"There's going to be an endless series of articles from this circle that is embracing this new theology built on very flimsy interpretation" of hurricane data, Mr. Goldenberg said. "If global warming is having an effect on hurricanes, I certainly wouldn't base it on the articles I've seen."