Dean = Global Warming?

[Downdraft]

At the risk of starting a heated discussion just my two cents about Dean before the GW side uses it as a banner I'd like to remind everyone that Dean was a perfectly natural system considering the circumstances. The hurricane did it's job of transferring latent heat energy from the tropical waters to the atmosphere but since it was blocked from moving north to distribute that heat back in the form of rain over cooler waters it had no choice but to move west continually feeding on more latent heat. Systems that stay in the tropics and moving west have a habit of becoming monsters. For that reason Dean is not an example of a global warming affect. I suppose this could be a good debate if we can keep it to science and leave passion out of it. Bear in mind the word hurricane comes originally from this area and the Maya who lived there long before global warming was even a thought. I believe the original word was Hurkan or something like that. To the Maya it was a large evil ocean god that rose from the sea to destroy everything in it's path. The word was embraced by the Carib Indians and later became hurricane to the Spanish. Just some trivia thrown in.

[HURAKAN]

Huracan

In Maya mythology, Huracan (also Hurakan, from Mayan Jun Raqan "one legged") was a wind, storm and fire god and one of the creator deities who participated in all three attempts at creating humanity. He also caused the Great Flood after the first humans angered the gods. He supposedly lived in the windy mists above the floodwaters and repeated "earth" until land came up from the seas.

In appearance he has one leg, the other being transformed into a serpent, a zoomorphic snout or long-nose, and a smoking object such as a cigar, torch holder, or axe head which pierces a mirror on his forehead.

He was also mentioned in Grace Nichols' poem Hurricane Hits England where she makes references to the caribbean gods.

His name is the source of the words hurricane and orcan (European windstorm).

Alternative names: Hurakan, Harakan, Tohil, Bolon Tzacab, K'awil (Kauil), and Heart of Heaven (in Popol Vuh). The deity also had resemblances to the god worshipped by the Aztecs as Tezcatlipoca.

http://en.wikipedia.org/wiki/Huracan
________________________________

Dean was a classic hurricane in the Atlantic Ocean. The type of hurricanes that you here when experts talk about the greatests of all time. Dean was not a result of Global Warming. Take it from HURAKAN!!!

[x-y-no]

This is a topic which has been fairly well beat to death both here and in many other venues. Attributing any single weather event to global warming simply isn't valid, as practically all climate scientists would agree.

What can be legitimately said is that there's some good reason to think that in a global climate with substantially higher oceanic heat content in the tropics, one would expect a higher proportion of those cyclones which do form to become intense storms. This is hardly settled science since there are significant difficulties with the earlier statistics on storm frequency and intensity, but it makes considerable physical sense.

[Zardoz]

New Atlantic Basin Top 10 Intensity List:

1) Wilma - 2005 - 882mb
2) Gilbert - 1988 - 888mb
3) Labor Day - 1935 - 892mb
4) Rita - 2005 - 895mb
5) Allen - 1980 - 899mb
6) Katrina - 2005 - 902mb
7) Camille - 1969 - 905mb
7t) Mitch - 1998 - 905mb
9) Dean - 2007 - 906mb
10) Ivan - 2004 - 910mb

And 5 of them in the last 3 years.

Does this mean nothing at all?

[HURAKAN]

New Atlantic Basin Top 10 Intensity List:

1) Wilma - 2005 - 882mb
2) Gilbert - 1988 - 888mb
3) Labor Day - 1935 - 892mb
4) Rita - 2005 - 895mb
5) Allen - 1980 - 899mb
6) Katrina - 2005 - 902mb
7) Camille - 1969 - 905mb
7t) Mitch - 1998 - 905mb
9) Dean - 2007 - 906mb
10) Ivan - 2004 - 910mb

And 5 of them in the last 3 years.

Does this mean nothing at all?

In this active period we're living we should be expecting more storms, including very strong storms. Now we have the equipment to measure the intensity and lowest pressure even if the hurricane is between Puerto Rico and Bermuda moving into the central Atlantic. In the 1930s, 40s, 50s, and 60s, we had a similar active period, but there was little equipment available to measure the strongest winds and the lowest central pressure. Before satellite era most reports came from landfalls and ship encounters, some from hurricane "hunting" by aircrafts, that why today we have "Hurricane Hunters" and not "Hurricane Investigators"!!! In the early years if a storm like Dean made landfall, all the equipment would fail rather easily and it was very difficult to differentiate a Cat. 4 (135 - 155 mph) from a Cat. 5 (156 mph +). Therefore, it's not a surprise we have seen so many records fall over the past few years and it's simply because we are living in an active period in the Atlantic and we have better equipment. The world is not ending, not yet.

[Frank2]

If nothing else, it is very impressive, in a sense, to see one severe hurricane after another - it seems to have become a common event...

Aside from Camille, which was a rare event at that time, I can't recall seeing this type of hurricane in the 1960's, '70s or '80s (with the exception of Allen and Gilbert)...

The "typical" major hurricane of the '60s or '70s (or even earlier) seemed to be the very wet Category 3 or 4 hurricane - the "shark's eye hurricane" common with severe hurricanes (that seem to be common today) was not common at that time...

However, it is interesting that the 1935 Labor Day hurricane was also of this class, so, that's an argument against Global Warming...

Perhaps, with the above information, it could be said that the incident of severe hurricanes is increasing - from one every two decades, to one every other year...

Just my own observation...

Frank

[terstorm1012]

Active cycle, Zardoz and better observational equiptment that did not exist during the last active cycle (and I'm one who accepts many of the conclusions of the latest IPCC series of reports...just not what currently keeps getting said on tropical cyclones.)

[terstorm1012]

What can be legitimately said is that there's some good reason to think that in a global climate with substantially higher oceanic heat content in the tropics, one would expect a higher proportion of those cyclones which do form to become intense storms. This is hardly settled science since there are significant difficulties with the earlier statistics on storm frequency and intensity, but it makes considerable physical sense.

right, intuitively it would make sense, but it's not matching up with the still young and growing paleotempestology studies that are coming out, including the latest one that was in Nature in May (5,000 year record, el nino, african monsoon and all that jazz...I have the paper around here somewhere........)

[njweather]

Dr. Kevin E. Trenberth, head of the Climate Analysis Section at the National Center for Atmospheric Research, sums it up best: "It should be recognized that the issue is not black or white, but rather that global warming has a pervasive influence on ocean SST [sea surface temperature] and heat content, atmospheric temperature, water vapor, and atmospheric and oceanic general circulation patterns, all of which affect tropical cyclones in complex, not yet fully understood ways." and "in our view the growing body of evidence suggests a direct and growing trend in several important aspects of tropical cyclones, such as intensity, rainfall, and sea level, all of which can be attributed to global warming."

So, while all storms may not be related to GW, the characteristics that affect them certainly are.

[Steve]

>>Dean was not a result of Global Warming.

What is cause and what is effect? We're clearly in a warm phase (cyclical, manmade or not or whatever) overall as many of the last several years have featured record setting heat (by month, entire year or whatever) for countries*, continents, etc. There isn't even a debate that the our country and continent are warmer than since we started keeping records (1860's?). I'm not about to get into the idea of what causes it, though I lean toward the idea that it is a natural cycle with a few steroids compliments of trillions of cubic feet of pollution that we have added into the mix.

The bottom line is the number of super intense hurricanes have increased. And don't anyone say we didn't have the technology in the past. The re-analysis work pretty much looked at every storm over the last many decades prior to the technology. If nothing else, we have a reasonable to very good idea of the strength of those storms even if we missed a few in the upper Atlantic where they generally aren't incubated to Cat 4 or Cat 5 anyway.

As for the "Does this mean nothing at all" comment, that's specious at best. If 5 of the strongest hurricanes in our basin in at least the last 90-140 years came in the last 3 years, well even the least informed among us should give pause to that idea. And if we continue to see a marked increase in IH storms in given seasons regardless of whether we're in an Atlantic warming or cooling phase, then something is either out of whack or we're possibly in the midst of a cycle or period in that cycle that escapes man's recorded history. Dr. Vanheerden (can't ever remember how to spell his name) who heads the LSU atmospheric sciences area has speculated that we're possibly in some overlapping 30 year and 1,500 year cycle. Again, I'm not hyping this as some harbinger of doom based on mankind's willful pollution. I'm just saying that maybe the earth goes through periodic hyperwarming phases or maybe hyper storm cycles.

All the Rush Limbaughs or Al Gores of the world are not going to be rational about the point. People are way too passionate about their point of view (Go Red Team vs. Go Blue/Green Team!) to look at the reality of the science there before us. Conclusion: WE DON'T KNOW.

* 2006 was the warmest year on Record for the United States and almost directly mirrored 1998. http://www.noaanews.noaa.gov/stories2007/s2772.htm

* 2005 was the second (3rd now) warmest year on record:
http://news.mongabay.com/2005/1216-weather.html

* 1999 was the second (4th now) warmest year on record:
http://www.publicaffairs.noaa.gov/relea ... 99083.html

* 2000 Jan-March warmest first 3 months on record:
http://www.sciencedaily.com/releases/20 ... 080006.htm

So for anyone saying this is just a repeat of the 1940's-1968 Atlantic Warming Phase, you're out to lunch. This is bigger, hotter and different from any period we've experienced.

Give up the rightwing political hype and leftwing enivornmental hype and let's observe and see if there is anything to all this or if it's just a natural situation that we'll have to bear through just like a mini-ice age.



Steve

[Fego]

Besides the Mayas, the "Taínos" in the Caribbean used the word "Juracán" as an "evil god" name. Something interesting in common between two different cultures.

[x-y-no]

A question for those who think there is no connection between global warming and more intense cyclones:

Since oceanic heat content is a well-understood contributor to cyclone intensity and a warmer climate clearly leads to higher average oceanic heat content, there must be some other effect of global warming which counteracts this if there is to be no enhancement of cyclone intensity.

What is this effect and what evidence is there to support it?

[tolakram]

Does this mean nothing at all?

How accurate are the records going back over a hundred years or so? Anyone looking at 100 years worth of data and trying to forecast a trend, it seems to me, would be foolish. This is NOT a comment on global warming but rather a comment on the recent hurricane activity.

To add:

Would global warming lead to more El Nino events and if so how would that effect hurricane activity?

[Downdraft]

Are we seeing more intense cyclones in all basins? Since global warming is a planet affect than shouldn't this type of activity be mirrored in all basins? Again, I'm not beating a dead horse to death and would love to strictly limit the debate to the science of it. So far, some very excellent replies.

[HURAKAN]

A question for those who think there is no connection between global warming and more intense cyclones:

Since oceanic heat content is a well-understood contributor to cyclone intensity and a warmer climate clearly leads to higher average oceanic heat content, there must be some other effect of global warming which counteracts this if there is to be no enhancement of cyclone intensity.

What is this effect and what evidence is there to support it?

Then the question we should ask ourselves is, with the help of Global Warming, how strong would storms get?

Lets say global warming increases 10% of a cyclones intensity. Then a 100 mph hurricane would be a 110 mph hurricane.

How can we measure that?

With what reliable data can we compared today's storms with past seasons' storms?

Conclusion: It's too early to say because we don't have reliable data going back to long period of time. We still have more questions than answers.

[x-y-no]

Hurakan:

Those are fine questions and I don't dispute their validity, which is why I said earlier that "there are significant difficulties with the earlier statistics on storm frequency and intensity."

But what I was seeking was more in the nature of a thought experiment: what countervailing effect might there be and what evidence do we have for such an effect?


Tolakram proposes this possibility:

Would global warming lead to more El Nino events and if so how would that effect hurricane activity?

which is an interesting thought ... but as I understand it el Nino will in general enhance Pacific activity as it suppresses Atlantic activity. Also, I'm not aware of evidence for an increase in number/intensity of el Nino events.

[Sanibel]

Dean is simply too powerful an event to determine what percentage was due to global warming. It would be more appropriate to see Dean in more long-term statistics to see how he fits into increased occurrence of strong cyclones etc.. The exact global warming influences would be more subtle, like in slightly increased SST's, or slight increases in the number of strong storms and intensity. It would be easy to hide these influences in general statistics and average occurrence rates in climatology.

[terstorm1012]

Are we seeing more intense cyclones in all basins? .

I don't have it in front of me, but I believe the answer (right now) is "maybe."

I also think what I read in the IPCC report was that there won't be more storms globally, just that the ones that form will be more intense. For what it's worth 2006 was down for TC activity globally except in 2 basins.

[Sanibel]

There could be other things you might miss. Like global warming increasing the strength of synoptics like the ridge that guided Dean down to the lowest track of an August CV storm in climatology.

It is hard to translate GW into all basins because it might not be a direct relationship. GW could change ocean and weather patterns making previous active belts disrupted and enhancing others.

[Downdraft]

Another thing to remember is Dean stayed in the tropics with nothing in the synoptic environment to keep it from intensifying. Had Dean moved north out of the tropical seas it probably wouldn't have become so strong. So again, how does a warmer basin affect the Atlantic Ridge? My original point was and still is you can't use Dean one way or the other because it took path that never allowed it to go north thus, it had constant fuel upon which to feed. The other side of the issue is the Atlantic Ridge itself and whether we will see more intense hurricanes because they are forced to remain at lower latitudes. So many questions with no definitive answers at the moment.