Figure 10 shows results when a different assumption is made concerning the behavior of water vapor. The predicted change in storm frequency is shown in Figure 8b. Figure 10 shows how sensitive the predictions are to the assumptions made about the behavior of water vapor in response to global warming. It makes a huge impact on the results, changing the trend from a slight decrease to a dramatic increase in storm frequency. As with the GCM-based temperature trend predictions, understanding the responses of water vapor, precipitation and clouds to additional forcing (be it from CO2, the sun, volcanic activity, aerosols, etc) are vital to understanding climate, and current understanding in this area is very poor. Prof. Emanuel is very honest about this in his paper.

Nice theory. Of course the author has flip-flopped from his last paper and one more trivial detail - ocean temperatures are lower now than they were 30 years ago. The whole premise of the study is fatally flawed.
http://vortex.nsstc.uah.edu/data/msu/t2lt/uahncdc.lt

I doubt if any model to predict climate will ever exist (unless you could predict sun/space activity)

I have read extensively over the weekend about Kerry Emanuel`s reversal and the main message I got was his earlier position linking hurricanes to global warming was no longer valid. Also, I have been reading about food riots across the world and the production of biofuels is being blamed for shortages and high prices. Wasn`t biofuels suppose to be one of the solutions to combat global warming? And lastly, in the April 14, Wall Street Journal there is an article about the fraud and abuses of the carbon cap and trade system in Europe. Wow! talk about unintended consequences.

Warning: This article talks about frequency and intensity.

Southern Hemisphere - Increase in intensity, small decrease in frequency.

Western Pacific -- Increase in intensity

North Atlantic -- El Nino a powerful force. But a decrease in frequency and increase in intensity.

This is consistent with what we have experienced recently.

Weather isn't climate.

Intensity and frequency are separate.

Consistent with climate change theory.

I does seem strange that one of the major AGW proponents cannot seem to make up his mind. In 2005-2006 he led the way giving his imprimatuer to the theory that GHGs drive NATL Hurricanes. Now 3 years later, he does an about face -sort of. Talk about hedging ones bets: a decrease in number over a 200 year period, but an increase in strength and duration... Didn't Emanuel know in 2005 that ENSO generated verticle wind shear works against TC developement? There were a few skeptics that pointed this out in 2005, but they were branded denialists.

But, in Emanuel's theory, GHGs still drive TCs. ENSO is driven by GHGs. In Emanuel's estimation there will be fewer NATL Hurricanes due to more frequent EL Nino outbreaks. But the potential energy will still be there, and when Hurricanes do develope they will therefore be more destructive. The one catch to this theory is that no one can tie ENSO to AGW. As a matter of fact, the tropics should see its warming aloft and not at the surface (according to the IPCC AGW/Stephan Boltzman theories).

FRom CSM: "His team drew its results from a new modeling approach it developed."

A 'new modeling approach'.....

'NUFF SAID

I love the to and fro of the scientific process. It's uncertain and messy but, as with life, it evolves. Emanuel's previous report predicts decreased tropical cyclone activity- but he's not sure why- "perhaps as a consequence of increased vertical wind shear". In his new report he experiments with new ways of looking into the future with GCM's, but recognizes throughout the report that it is a relatively crude and simplistic experiment at this point and there is much more to come. I personally would change the "Should" in the blog headline to "May".

Let me see if I've got this straight:

1)The ARGO network of ocean temperature monitors shows no net increase in ocean temps while it has come on line during the last 3 to 4 years, and in fact a slight decrease.

2) Many people from the IPCC down will now admit that surface temps have been declining over the last decade (even though the global average is about the 1950 to present "norm") even though CO2 emissions have continued to increase.

That about it?

Okay. So how does it make any sense to publish a paper that makes a projection based on the assumption that your previous projections were correct in the face of REAL data that suggests that they were not. Personally, I would have been embarassed to submit something of that nature, as would have been my professors.

All the best

Aaron

Last year, the early spring in the midwest was cited as proof of global warming. Conversely, the very late spring this year must be proof of global cooling.

"I'm 71-years-old and I've never seen spring come this late," Robert Ciesleck said.

http://www.kcrg.com/news/local/17646694.html

Remember - early springs are "climate." Late springs are "weather."

Well - what causes hurricanes? There's stuff like the coriolis effectm, but the main driver is usually accepted as the abrupt temperature gradient between the tropical and temperate zones, right?

According to AGW the tropics will not warm very much, but the the temperate and polar zones will warm by up to 8C - i.e. the temperature gradient between the tropical and temperate zones should reduce - so hurricane frequency and severity should also reduce, and the hurricane zone will move North.

It made no sense that the record breaking 2005 hurricane season was blamed on AGW, but then AGW proponents seem to leap on ANY extreme weather event as evidence of AGW.

Here in the UK, the summers of 2006 and 2007 were both extreme, but for very different reasons. Summer 2006 was record breakingly hot. Summer 2007, by contrast, was cool and record breakingly wet.

In both years scientists warned us that such extreme summers would become more likely due to the effects of AGW, but how? These summers were completely opposite in their nature.

If hot, oppressive weather becomes more likely, then how also can cool, wet weather become more likely too? Did something major change in AGW theory between summers 2006 and 2007?! Or is it just that the weather changed from one extreme to the other, so the story had to change too?

This is why people become sceptical....

Concerning frequency of tropical storms and hurricanes. The recent stats are skewed relative to long term norms due to greater powers of observation and in my opinion the hurricane center names disturbances that wouldn't have been named even 15 years ago.
Like temperature comparisons influenced by heat islands or change of location for local station this makes it difficult to know with assurance how much difference actually exists in the climatology.
Never mind if "global warming" is a cause of change.

Fewer hurricanes? Sounds like a good thing to me! What's the downside?

Oh how I wish, I wish, I wish, that global warming comes back soon.

The one good thing I see in this thread is that a scientist is willing to change his mind. That is refreshing compared to the rigid dogma we have been fed in the last few years (20 in the case of Hansen).

Hi John,

There was great press release last week from The Met, basically saying that this year's London Marathon was going to be cold - but in future years runners will have to deal with heat because of global warming. They appear incapable of giving a simple weather report any more without mentioning "global warming."

http://www.metoffice.gov.uk/corporate/pressoffice/2008/pr20080411.html

What I read from Emanuel's jibberish is the original prediction model was just a test, the new improved "higher resolution Model", a result of my last grant looks better but still needs a lot of work. This of course will require a lot of money, etc. that will give us the "elevated higher resolution model" which will of course provide us with the chance to see that we need a hyper higher resolution model that will take a huger amount of money that will prove the previous models forgot to include something. And the final model he will call "Vista" which will be perfect.

The people that made all the money from the
Klondike gold rush were not the ones that dug it up but the ones who found the men that had the gold. The hustlers. Our professor Emanuel?

Jep says:
"Fewer hurricanes? Sounds like a good thing to me! What's the downside?"

The downside is more intense storms. The downside is much of the western Pacific will have more storms and deadlier storms.

Pacific cyclone activity has been very intense in recent years.

The downside is that,for the first time two Cat 5 storms hit the Americas last season.

This new result is not out of line with previous findings. Emanuel's work also tends to vindicate models.

" The findings presented here are largely consistent with those obtained by direct simulation of tropical cyclones by global models as well as by downscaling using regional models embedded in global models."

The downside for the US is fewer hurricanes but more Cat 4 and Cat 5 storms.

PH -- The paper discusses the relation between El Nino and hurricanes.

Read the paper before commenting. Too much knee jerk denials.

Getting back to the basis of the scientific process. It is not about achieving a perfection. It is about positing a hypothesis; checking it against data in well designed experiments; peer review; making it public; getting critiqued; modifying the hypothesis and doing it again. It is not about being a flip-flopper when a new study shows new findings leading to a modified hypothesis. While in some areas (mainly physics) it is possible to progress from hypothesis to theory to law, in most it can never go beyond theory (I think it's still a theory that the Earth revolves around the Sun).

Off Topic.....
Antarctic warming not Man Made:
http://www.antarctica.ac.uk/bas_research/our_views/climate_change.php

Excerpt:
Here, annual mean temperatures have risen by nearly 3�C, with the largest warming occurring in the winter season. This is approximately 10 times the mean rate of global warming [Hence not caused by it], as reported by the Intergovernmental Panel on Climate Change (IPCC).

RealClimate admits GCM are note climate predictions but just scenarios to test sensitivity:
http://climatesci.org/2008/04/11/real-climates-agreement-that-the-ipcc-multi-decadal-projections-are-actually-sensitivity-model-runs/

Excerpt:
Now, from an unlikely source (Real Climate) have come the statements �A scenario only illustrates the climatic effect of the specified forcing - this is why it is called a scenario, not a forecast.

John:

Very well done, I have said just about the same thing for years. Mind you, I'm not an esteemed, consensusly approved, climatologist.

I look at it quite simply that there is less potential difference between the air masses thereby reducing the energy available for development.

Here in the Ohio, USA, I desperately look forward to July and August not because I like hot weather but rather that the air mass around us is more stable relative to potential heat. With the air stable, we get less storms, if any, and those that do pop up are short lived. Therefore, less damage. The rest of the year, cold air drops from the north and we get convective storms that cause problems one way or the other. Mind you, we do not lack for rain either as it can rain it is just that the potential for severe weather is lessened.

Ronnie:

Also, well put, there is something to be said for the naming of a storm that only the fish can see. I'm not sure what that is though. It almost seems that someone (or rather an agency)gets a performance bonus for the naming of a storm since clearly, they need to protect the "people".

Not that I'm saying anything or nothin'.

Just wanted to make it clear to everyone, especially Mark and BT, that I did my part today to enhance Glo-BULL Warming by having, not one, but 2, yes, that's 2 (TWO!!!) Arby's Roast Beast sandwiches for lunch. And they WERE YUM YUM YUMMY!!!!.... So ladies and gents, if you want to curtail the number of hurricanes, et.al. every year, EAT MORE BEEF!!!!!..WOO HOO!!!!..AND A BIG WARM UP IS ON THE WAY!!!!! (Sorry, Brett, but I will believe that when I believe it!).......

DENY DENY DENY THE GLO-BULL WARMING LIE!!!!!!

When was the last cat 5 hurricane to make landfall in the US? Camille? While record low central pressures of hurricanes have recently been measured in the tropics, these hurricanes have not impacted the US with commensurate strength. In 2005, global warming did not produced catastrophic US landfalling hurricanes. Both Rita and Katrina were Cat 3. Camille was the last catastrophic US hurricane; when the earth was cooler! And, well before that, there was the Long Island express of 1938. Now it looks like global cooling is upon us, so we probably should be worried about another Camille.

It does seem strange that one of the major AGW proponents cannot seem to make up his mind.

Come on, JP -- now you're busting his chops for doing exactly what a scientist is supposed to do. This isn't an athletic contest, it's not a religion, and it's not a political party.

Emanuel publishes his best efforts to describe and interpret what he sees based on the data and theory available to him. In the presence of new data and/or new theory, he revises his position.

Isn't that what good science is about?

Would you have him dogmatically maintain the same stubborn posture, regardless of the data and theory unfolding around him, because of work he published three years previously? Sounds more like Ball, Lindzen, or Gray to me.

Patrick,

ocean temperatures are lower now than they were 30 years ago.

Ocean temperatures were cooler than today in 1992, 1993, and 1999 (to name a few)--much more recently than 30 years ago. In 1999, they occurred just 14 months after the record-warm temperature was set. I don't want to accuse you of cherry-picking again, so please explain the implications of your point. From my understanding, it is quite normal for ocean temperatures to dip during a La Nina event. The 1999 data shows that they dropped much more dramatically then than they have in the current La Nina.

In fact, from the UAH data you provided, it appears there was a nine-month stretch from 1999 to 2000 where ocean temperatures were below "normal." During the recent stretch of cold weather, ocean temperatures have been below normal for one straight month. How does this support your recent arguments that we've begun a historic cooling trend? You say global temperatures have decreased since 1998. I contend that they have increased since 1999!

Gettingwarm

"Intensity and frequency are separate. Consistent with climate change theory"

Thus everything is consistent with the theory and nothing can ever be inconsistent with the theory.
Is that how the theory goes?