Global warming to necessitate Category 6 designation?

[mtm4319]

http://abcnews.go.com/GMA/Science/story?id=1986862

By BILL BLAKEMORE

May 21, 2006 — - There is no official Category 6 for hurricanes, but scientists say they're pondering whether there should be as evidence mounts that hurricanes around the world have sharply worsened over the past 30 years -- and all but a handful of hurricane experts now agree this worsening bears the fingerprints of man-made global warming.

In fact, say scientists, there have already been hurricanes strong enough to qualify as Category 6s. They'd define those as having sustained winds over 175 or 180 mph. A couple told me they'd measured close to 200 mph on a few occasions.

The Saffir-Simpson hurricane category scale is based on wind speed: A Category 1 hurricane has sustained winds from 74 to 95 mph, Category 2 has sustained winds from 96 to 110 mph, Category 3 has sustained winds from 111 to 130 mph, Category 4 has sustained winds from 131 to 155, and a Category 5 storm has sustained winds greater than 155 mph.

The categories run in roughly 20 mph increments, so a Cat 6 would be greater than 175 or 180 mph.

"Remember, for each 10 mph increase of wind speed," says atmosphere scientist Greg Holland, "there's about 10 times more damage, and 20 times more financial loss."

In other words, the increase is not "linear" but "exponential."

To put this all in perspective, Katrina was a Category 5 hurricane out over some hot spots in the Gulf. But when it hit New Orleans, scientists now know, Katrina had winds at a low Category 3, and much of them Category 2, including the "left side winds" that then came down from the north and pushed the surge-swollen waters of Lake Pontchartrain over and through NOLA's levees. (Hurricanes spin counterclockwise in the northern hemisphere, so when Katrina came ashore just east of New Orleans, its winds hit the city from the north.)

Only three Category 5s have come ashore in the United States in the past century -- the 1935 Labor Day Hurricane, Camille in 1969 and Andrew in 1992.

But because of man-made global warming, most hurricane scientists say now we will probably be getting Category 4 and 5 hurricanes more frequently in the coming decades.

That's on top of the natural multi-year cycles of hurricane intensity the scientists already know about.

In fact, says Greg Holland, the world already has seen far more frequent Cat 4s and 5s. He points to several studies published over the past 12 months which "indicated the frequency of Category 4 and 5 hurricanes had almost doubled around the world in the period since 1970."

The fact that these patterns (on top of the natural cycles) have been seen in not just one ocean but all tropical and subtropical waters around the world is what worries many hurricane experts -- and, they say, it is why they now calculate that they are due to man-made global warming, not regional natural weather patterns.

"We're actually looking at an entire world that is heating up," says Holland, "not just the Atlantic Ocean -- which is why we are absolutely convinced that there is a very large greenhouse warming signal in what we're seeing."

In the past, say these scientists, when one region of the globe concentrated more heated water or air (both of which can intensify hurricanes), other regions would cool in compensation because the total heat available on the planet at any one time is limited; now, with the average global temperatures going up, such related cooling is happening less and less.

Greg Holland's research base -- the National Center for Atmospheric Research in Boulder, Colo. -- receives overwhelming evidence for the human contribution to global warming constantly now, challenging NCAR's ranks of world class climatologists (and their sleek black humming supercomputers in the basement) to produce ever more refined predictions of the planet's rising fever over the next few decades.

How well did the National Oceanic and Atmospheric Administration do a year ago in predicting the 2005 Atlantic hurricane season? Not so well, and the relatively new and unfamiliar factors of manmade global warming, say some scientists, may be part of what threw last year's predictions off.

In May 2005, NOAA predicted the summer Atlantic would see 12 to 15 named tropical storms. There were 28. It predicted seven to nine storms would become hurricanes, with winds of at least 74 mph. Fifteen did. It predicted three to five of the hurricanes would be "major," with winds of at least 111 mph. Seven were, and four of them came ashore in the United States.

A "Category 6?"

Making that official, say several hurricane scientists, would require sober deliberation by their guild, assessing whether there would be any real advantage to it -- even though it seems reasonable to expect that the frequency of storms we have already seen with sustained winds over 175 or 180 mph may indeed creep up as the globe keeps warming.

Category 5, they point out, is already bad enough, way beyond almost everyone's ability to imagine, given that Katrina came ashore as a 3.

Copyright © 2006 ABC News Internet Ventures

[Camille_2_Katrina]

that's plain silly talk...

[x-y-no]

I don't see any point in doing this.

[skysummit]

that's plain silly talk...

Hey...I agree with you!

[feederband]

Cat 5 is good enough...If you don't leave for a cat 5 you probably wont for a cat 8 either..

[SouthFloridawx]

Yeah seriously this discussion always ends up the same every time.

[Camille_2_Katrina]

Cat 5 is good enough...If you don't leave for a cat 5 you probably wont for a cat 8 either..

[mtm4319]

I don't see any point in doing this.

Me either. This sums it up pretty well:

Category 5, they point out, is already bad enough, way beyond almost everyone's ability to imagine, given that Katrina came ashore as a 3.

You'd be talking about creating a category for wind conditions experienced on land maybe once every 30 years. All this kind of talk does is mislead the public into believing that lower categories are not as significant. Heck, if they need to make any changes, they should subsume Cat 5 into Cat 4.

And of course, their underlying agenda is blaming it all on SUVs and global warming.

[Hyperstorm]

If we add another category, people will think a category 5 is not top scale and will not leave. We just have to leave this as is in the immediate future. If we start seeing storms going over 175 mph at a regular basis, then maybe in 5-10 years we can discuss the possibility.

In the meantime, a category 5 is about as catastrophic as it can get...

[skysummit]

Plus, I don't think we'd see much difference when it comes to damage between 165mph and 180mph. Everything would be destroyed regardless.

[terstorm1012]

I think the categories are fine as they are personally and adding categories isn't necessary.

[Stratusxpeye]

Plus, I don't think we'd see much difference when it comes to damage between 165mph and 180mph. Everything would be destroyed regardless.

Agree only difference might be that even the grass would be gone by wind inland not by water on the coast if the winds were higher than 170 or so on land. Possibly even so dirt blowen around and make some hills become flatland Cat 6 would make ppl think lesser of lower categories. And some ppl already don't take threats seriusly.

[stormcloud]

There just isn't much above "catastrophic destruction."

[skysummit]

Yea....what would Cat 6 be? "Totally Obliterrated"?

[Derek Ortt]

and the author has lied

There is NOT a consensus as to whether or not the recent increases is due to global warming. There are many other man made factors, such as calling 4's and 5's in the past, especially in the Bay of Bengal, as category 1's and 2's, or Australlia for 10 years refusing to say a TC had winds higher than Tracy

[Hybridstorm_November2001]

I agree. Stick with cat 5 as the high end.

[MWatkins]

I think we've pretty much demonstrated that the studies used to make the assumption that Cat 4 and 5 hurricanes are on the rise have been debunked due to methodology issues and/or an outright artificial reduction applied to the post 1970 dataset by one of these researchers.

To me this is yet another attempt to get Global Warming on the front page and link it to something people worry about. Is it a coincidence that this article was put out the day before the NOAA hurricane outlook was released? Is ther any real news or science beyond the opinion of Greg Holland on that article? No.

In fact, and I don't know much about print media nor did I write for my school paper, the article references "some scientists" twice to draw conclusions, neither reference is to Greg Holland directly. So who are these scientists?

It seems more like an op-ed piece disguised as news.

But then again nobody really cares if articles about science actually have any real science in them, right?

MW

[x-y-no]

Sometimes poor reporting is just poor reporting, not lies or conspiracy.

The author certainly gets some important things wrong, most glaringly the notion that "all but a handful of hurricane experts" are persuaded that global warming results in more and more extreme tropical systems. But then again I've never looked upon "Good Morning America" as a shining example of journalistic excellence.

I'll write the author an email urging a correction.

EDIT: or I would if I could find his email ... I don't want to waste my time sending to the generic address ...

[Aslkahuna]

Three papers were presented at the AMS Conference dealing with the need for reanalysis of the WPAC database noting that until it was optimized to the same standard as the ATL database that any inferrences could not be made regarding the presence or absence of a Global intensity signal. It was also mentioned that the NIO and Southern Hemisphere databases were in even worse shape and EPAC also needed work. Yet Blakemore has totally ignored those so his agenda is obvious and I'll have to leave it at that because the slippery slope beckons.

Steve

[MWatkins]

Sometimes poor reporting is just poor reporting, not lies or conspiracy.

Agree. However, if I did want to get an article out there I would release it in the last 14 days before the season starts, that probably has more to do with the timing than anything else.

Besides, once you start throwing around the phrase "Category 6", people do tend to take notice.

MW