Storms like Katrina a yearly thing?

[Anonymous]

In these active periods...powerful landfalls annually are common...

1945- Two Cat 4 USA
1946- Major USA
1947- Cat 4 USA
1948 Two Majors USA
1949- Two Cat 4 USA
1950- Easy in FL
1951- MAJOR CHARLIE FOR CARRIBBEAN
1952- FOX INTO CUBA

[calculatedrisk]

Dr. Gray addressed frequency, not intensity. Frequency is addressed very nicely in Dr. Gray's forecast:
http://hurricane.atmos.colostate.edu/Forecasts/2005/aug2005/

However global warming will lead to more intense hurricanes, but not more frequent hurricanes:

“The general scientific consensus on climate change and hurricanes is this: Hurricanes won’t necessarily become more frequent, but they will become more intense. While ocean and atmospheric circulation is the engine of a hurricane, heat is the fuel. ... Thus, when other factors line up to form a storm, a warmer ocean means it will be all the more powerful and destructive.”

http://www.emagazine.com/view/?2865

And the statement: "melting ice caps would cool the oceans" would be correct for a closed system, but since the entire system is warmer (hence the term "global warming") the melting ice caps would not cool the ocean. This is apparent since the ice caps are melting and the ocean temperatures are setting records!

And here is an excellent report on ocean warming:
http://www.aaas.org/news/releases/2005/0217warmingwarning.shtml

[oneness]

My opinon:
To accept that in one hand global warming is happening , and then on the other hand say it has no real bering on hurricains is sticking your head in the sand. If at their core hurricains are heat/energy/moistier transport to northern latitiudes , and global warming adds more of that of course hurricains will be effected.

Cyclonic activity in the SW Pacific and northern Australia has been much lower since the end of the 1960s and 1970s rash of storms. In north-eastern Australia cyclone numbers have been exceptionally low for many years now and at the same time we have been having some very hot summers. It takes a lot more than a hot summer and warm water to make a cyclone season. Any superficial excess heating level in the tropics (assuming there actually is any NET rise) is not translating to enhanced cyclonic activity, just the reverse. The cycle will come back again. We have reasonably good cyclone occurrence records back to about the mid 1860s, and they do indeed come in multi year cycles, with pronounced breaks between peak cycle years.

(and if you study quaternary tropical stratigraphy and clast sizes, their geological unit derivation and transport it becomes clear that tropical storms of far greater intensity than modern humans see today have been occurring for millions of years)

[NorthGaWeather]

As to the pro mets. It's fine to put them on a pedistal , the do great work and are very knowledgible. They are also the first people that will tell you I'm sure they do not know many of the factors that go into a hurricain. If they knew all the angles forecasting them wouldn't be such a chore. My point was simply that real research on the effects of global warming linkage to hurricains is only now being performed. Thus one should keep an open mind and not just mindlessly tout 50 year old science.

We know a bit about how they form, what maintains them and so on. We don't know much about inner processes that strengthen, weaken a hurricane rapidly. There is alot we don't know but there is alot we do.

As to cycles. I'll make an annalogy here. If we are playing poker and I get delt poket Aces one hand , poket 2's the next , and poket Aces the 3rd. Does this now mean I can expect poket 2's on the 4th ? With all the other cobinations of cards that could come you would not make any money betting those odds.

Horrible analogy IMO.

In any case as that relates to my opinon on cycles in case it gets missed. We have what amounts to a snapshot of world atmoshpher during what geologists will be quick to site as an non typical "calm" period. If you think you can lay claim on the entire global weather for decades to come based on only 100 years of data , some of which is very questionable (early 1900's before radar / satalite / etc) , your making a typical mistake in my opinon.

We agree. You cannot make these huge assumptions, say about global warming and factors in it because we do only have 100 yrs or so of data. Thats why you can't say global warming is influencing it either. But we do have a picture of what has happened int he last 90 yrs or so int he Atlantic. We know some of the factors that led to the increased activity early in the 1900s and we know some that led to the lessened activity in the mid/late 1900s. So we can have a decent look on the Atlantic hurricane cycle. Chris Landsea wrote a good article on global warming and the affects on hurricanes. I suggest you read it.

Even Gray's product distinctly says , because he is obvisously a smart fella , that the whole forecast is based on the assumption that past data will give data to support future. Which means , it works on the assumption that history will repeat itself. If it does not and the idea of cycles was wrong he is covered. Smart man. It was I'll admit unfair to use the term "miss-information" when I responded I should have said it was his opinion.

In any case my whole point is we don't know and keep an open mind about whats to come. Don't lock yourself in a box and assume global warming does not affect these storms , wait for the real science to come in the years ahead. If you wish to stick with whats scientificly trendy , thats fine the world was flat once too.

Don't you know, history repeats itself.

Your right we don't know much about global warming so we shouldn't say its causing all of this.

[AussieMark]

Cyclonic activity in the SW Pacific and northern Australia has been much lower since the end of the 1960s and 1970s rash of storms. In north-eastern Australia cyclone numbers have been exceptionally low for many years now and at the same time we have been having some very hot summers. It takes a lot more than a hot summer and warm water to make a cyclone season.

Dont I know it

this past season the south Pacific had loads of violent cyclones wheras the Southern Indian was not very active in intense cyclone counts.

this is the opposite on whats its been some years.

its either one or the other that is active never both.

[Jim Hughes]

4. Lastly people don't like change , even if it's merly changing or opening up to the idea of something new. Global warming and the acceptence of it is new and you get the standard resistence to change even from the pro's.

I know exactly where you are coming from. It's amazing how many people want to blame everything on global warming or whatever . Nobody ever wants to look at the space weather effect upon climate patterns and it's staring them right in the eyes day in and day out....The Sun


Jim

[Patrick99]

So yes, more strong hurricanes in the future. But this will be because of the decadal cycles in ocean temperatures, not global warming. Eventually we will be back in a low-activity period like what we saw in the 70's and 80's, but before then we have to get used to the possibility of a Katrina for another major city.

Yeah, and we all know what other major US city will most likely come under the gun.

If we are in a repeat performance of the 1920s-1950, places like New Orleans and South Florida are really going to be hard put to it.

[ronjon]

Folks, with all this talk about global warming there is a completely natural reason we are seeing more intense hurricanes and well as more in the Atlantic Basin. It's call the Atlantic Multidecadal Oscillation (AMO). Dr Gray has written numerous papers along with Dave Enfield from NOAA. Chris Landsea & Stan Goldenberg have also discussed the subject from the Tropical Research Division of the NHC. Basically, the North Atlantic periodically goes thru cool and warm phases that each last roughly 20 to 50 years. Their is a deep ocean transport mechanism that transports very warm water from the tropics to the North Atlantic ocean. When this conveyor belt slows, the North Atlantic cools - when it speeds up, the ocean warms. Recent documented periods include: (1863-1895) warm, (1896-1920)cool, (1921-1969)warm, (1970-1994)cool, and post-1995 another warm period. Recent research (unpublished) by the Southwest Florida Water Management District, utlizing tree ring analysis from old cypress, has documented these cycles back to the 1700s. Other proxy data from isotope analysis from Greenland ice cores have documented these cycles back 12,000 years.

The exact mechanism that explains the slowing or speeding up of the warm water transport is poorly understood. During warm phases, we see increases in tropical cyclone activity in the Atlantic Basin and a higher frequency of major hurricanes. The opposite with cooler phases. Therefore, the increase in tropical cyclone activity is expected and natural.

Here is a good link for a recent paper in Science by Stan Goldenberg.
http://www.aoml.noaa.gov/hrd/Goldenberg/science01.pdf

[x-y-no]

Global warming has nothing to do with it. See Dr. Gray's explanation from August update. Keep in mind that if the planet's warming anything to do with frequency of hurricanes or intensity then those numbers would be up globally and they are in fact down since 1995.

http://hurricane.atmos.colostate.edu/Fo ... 5/aug2005/

One can no more state with confidence that GW "has nothing to do with it" than one could state the GW is the cause. There is now substantial research supporting the idea that warmer tropical and subtropical SSTs would be an effect of GW, and that this would lead to more intense storms on average (but probably not more frequency of storms).

The current increase in Atlantic activity is pretty well established to be related to the cycle which Dr. Gray and his team discovered (AMO). But this does not rule out that GW plays a part in the abnormal SSTs observed, and thus in the higher proportion of intense storms.

Additionally, common sense leads us to if the planet were warming significantly as some surmise, then the melting ice caps would cool the oceans; and we tropical weather afficionados know what that would do.

Now that's just pure nonsense. There's general subsidence in the arctic region, and any small cooling contribution of ice melt will be so mixed out in the abyssal layers and such a tiny part of the oceanic heat content as to be undetectable when it eventually wells up decades later.

[x-y-no]

A short article with some informative links and a pretty good discussion of this topic can be found here:

http://www.realclimate.org/index.php?p=173#comments

[Jim Hughes]

Now that's just pure nonsense. There's general subsidence in the arctic region, and any small cooling contribution of ice melt will be so mixed out in the abyssal layers and such a tiny part of the oceanic heat content as to be undetectable when it eventually wells up decades later.

I am going to play devils adovcate here and I am guessing that since the discussion was pointed towards the Atlantic hurricane season that the intention may have been pointed towards the North Atlantic. With that being said...The ice caps melting.....added fresh water...salinity effected...conveyor belt effected down the road .... although they never mentioned lag time time...nor even what or how it would be effected. Just a thought.


Jim

[x-y-no]

Now that's just pure nonsense. There's general subsidence in the arctic region, and any small cooling contribution of ice melt will be so mixed out in the abyssal layers and such a tiny part of the oceanic heat content as to be undetectable when it eventually wells up decades later.

I am going to play devils adovcate here and I am guessing that since the discussion was pointed towards the Atlantic hurricane season that the intention may have been pointed towards the North Atlantic. With that being said...The ice caps melting.....added fresh water...salinity effected...conveyor belt effected down the road .... although they never mentioned lag time time...nor even what or how it would be effected. Just a thought.


Jim

Well, since he was explicitly suggesting that ice melt in the polar region would cool the oceans in a manner which would impact tropical cyclogenesis, I'm afraid that interpretation won't cut it.

I stand by my statement that this was pure nonsense.

BTW Jim, I would direct your attention to the comments by K. Masuda in the realclimate.org article I cited above (particularly comment #32). You may find some fruitful material there regarding the questions I was raising to you about what mechanism would be involved in space weather affecting tropical cyclogenesis.

[Jim Hughes]

BTW Jim, I would direct your attention to the comments by K. Masuda in the realclimate.org article I cited above (particularly comment #32). You may find some fruitful material there regarding the questions I was raising to you about what mechanism would be involved in space weather affecting tropical cyclogenesis.

Thanks. I have read some small discussions regarding the solar/aerosol connection also....URL below

Like we have both mentioned ..it is complicated and it may take years before the exact truth is known. Some of these new satellites monitor everything and their collected data base will one day put an end to the arguement. One way or the other.


http://geo.phys.spbu.ru/magnetosphere/p ... ic/440.pdf


Jim

[linkerweather]

Now that's just pure nonsense. There's general subsidence in the arctic region, and any small cooling contribution of ice melt will be so mixed out in the abyssal layers and such a tiny part of the oceanic heat content as to be undetectable when it eventually wells up decades later.

I am going to play devils adovcate here and I am guessing that since the discussion was pointed towards the Atlantic hurricane season that the intention may have been pointed towards the North Atlantic. With that being said...The ice caps melting.....added fresh water...salinity effected...conveyor belt effected down the road .... although they never mentioned lag time time...nor even what or how it would be effected. Just a thought.


Jim

The point I was trying to make regarding the melting ice caps (apparently I didn't make it too well) was this....

The same people who argue that global warming is the cause for increased hurricane activity (by the way a proven fact that globally it has been down since 1995) are the same people who say that the melting of the ice caps from global warming will lead to massive sea level rises in europe and on the EC of the US. Now if you were to melt that much ice to raise the sea level across an entire ocean, you would absolutely cool the ocean. I was not suggesting that the ice caps are now melting and therefore the SST's currently are cooler.

[x-y-no]

The point I was trying to make regarding the melting ice caps (apparently I didn't make it too well) was this....

The same people who argue that global warming is the cause for increased hurricane activity (by the way a proven fact that globally it has been down since 1995) are the same people who say that the melting of the ice caps from global warming will lead to massive sea level rises in europe and on the EC of the US.

Perhaps you can explain exactly who it is you're talking about. I'd venture to say that the great majority of researchers who take anthropogenic global warming to be a very serious issue which warrants immediate action would nonetheless not claim that it would neccesarily cause a greater frequency of tropical systems. As I pointed out, OTOH, there is good research supporting the idea that the total cumulative intensity would be greater.

Nor am I aware of any serious researchers who believe that catastrophic ice cap melting or failure (for example the collapse of the West Antactic ice sheet) is anything but a remote possibility unless warming is allowed to run unchecked for a century or more.

Now if you were to melt that much ice to raise the sea level across an entire ocean, you would absolutely cool the ocean. I was not suggesting that the ice caps are now melting and therefore the SST's currently are cooler.

I undertood your point, and I still say it is pure nonsense. Melting at the rate projected by even the most pessimistic estimates might alter the mean location of arctic subsidence but is unlikely to shut it down. And even if it did, the resulting shutdown of the Atlantic conveyor would increase tropical SST's, since there would be less heat transport poleward.

EDIT:

Or just simply looking at volume ... the volume of the worlds oceans is about 1.3 billion cubic kilometers, which IIRC is at an average temperature between 4 and 5 degrees celsius. The total volume of the world's ice caps is about 35 million cubic kilometers.

So you explain to me how that relatively small amount of added volume which isn't too much cooler than the current average would make such a huge difference, especially since it would be concentrated in regions remote from the tropics?