Global Tropical Cyclone activity is at 33-year lows

Dr. Ryan N. Maue’s 2010 Global Tropical Cyclone Activity Update

Update to include Rush Limbaugh’s discussion on his radio show of this posting …

With the 2010 North Atlantic hurricane season winding down without a United States hurricane landfall, Drudge posted a headline suggesting that the seasonal hurricane forecasters blew it. Indeed, he has written this headline for 4-years in a row now by linking to my Florida State University website.  While the number of storms has been accurately predicted by the soothsayers (including Rush Limbaugh), the lack of impact upon the US mainland has left many wondering:  is this it?

While the North Atlantic sees ~10 storms per year, the annual global total is 80 to 90!  So, how is the rest of the globe doing in terms of tropical cyclone (TC) activity?  Absolutely cratering — and in in the Western North Pacific typhoon basin, at historical lows.  Indeed, with the Earth undergoing Global Climate Disruption, natural climate variability has played the ultimate trump card and left global TC activity at 33-year lows!




From my FSU website:


Current Year-to-Date analysis of Northern Hemisphere and Global Tropical Cyclone Accumulated Cyclone Energy (ACE) AND Power Dissipation Index (PDI) has fallen even further than during the previous 3-years. The global activity is at 33-year lows and at a historical record low where Typhoons form in the Western Pacific.

While the North Atlantic has seen 15 tropical storms / hurricanes of various intensity and duration, the Pacific basin as a whole is at historical lows! In the Western North Pacific stretching from Guam to Japan and the Philippines and China, the current ACE value of 48 is the lowest seen since reliable records became available (1945) and is 78% below normal*. The next lowest was an ACE of 78 in 1998.  The Northern Hemisphere overall (including the North Atlantic) has the lowest ACE since 1977, the year of the Great Climate Shift and flip in the phase of the Pacific Decadal Oscillation.

See figure below for visual evidence of the past 40-years of tropical cyclone activity.


Figure: Year-to-Date (October 7) Accumulated Cyclone Energy (ACE; units: 10^4 knots^2) for the Northern Hemisphere as a whole (top blue time series) and for the combination of the Western North Pacific (WPAC), Eastern Northe Pacific (EPAC), and Northern Indian (NIO) basins (bottom gray time series). The difference between the two lines is therefore the contribution of the North Atlantic hurricane basin. Similar figure for Power Dissipation Index (units: 10^6 knots^3)


…And global tropical cyclone during the past 33-years (Southern Hemisphere cyclone data gets progressively spotty prior to the routine monitoring of the global oceans by geostationary satellites):


Figure: Global and Northern Hemisphere Accumulated Cyclone Energy: 24 month running sum through September 30, 2010. Note that the year indicated represents the value of ACE through the previous 24-months for the Northern Hemisphere (bottom line/gray boxes) and the entire global (top line/light blue boxes). The area in between represents the Southern Hemisphere total ACE.


Global TC Activity remains at 33-year lows. — The last 24-months of ACE at 1090 represents a decrease from the previous months and a return to the levels of September 2009…Since Hurricane Katrina (August 2005) and the publication of high-profile papers in Nature and Science, global tropical cyclone ACE has collapsed in half. This continues the now 4-consecutive years global crash in tropical cyclone activity. While the Atlantic on average makes up about 10% of the global, yearly hurricane activity, the other 90% deserves attention and has been significantly depressed since 2007.

Atlantic Hurricane Season of 2010

Otto will soon be undergoing extratropical transition and succumb to the vertical shear which becomes progressively more hostile to hurricane activity in the Atlantic as the season wanes.  The number of storms ranks fairly highly in terms of the historical record — even with the paltry contributions by Bonnie, Gaston, and Nicole.  The ACE to date (October 8 00:00) is 137, which ranks 2010 as the 16th highest since 1950 just behind 2008.  Sorted List

Here is the yearly ACE total figure for the past 61-seasons (note:  no trend)


North Atlantic Accumulated Cyclone Energy based upon the HURDAT best-track archives.


While there are some qualms about the wind speeds prior to the satellite era, it’s clear that some sort of multi-decadal signal is present (i.e. AMO).  If some weak, short-lived storms were missed, then so what, their ACE contribution is inconsequential.  How does this ACE compare to the seasonal forecasts of NOAA, Gray and Klotzbach, and the UK MetOffice?  Not quite there yet.


2010 ACE to date (October 7), expected daily values based upon the 1950-2009 historical records, and various forecasting outfits' prognostications


How skillful or useful are these ACE forecasts?  Well, just based upon the knowledge of a La Nina summer/fall, one would calculate an average ACE of 116 compared to an El Nino average ACE of 68 by simply looking at the Multivariate ENSO Index and the hurricane records from 1950-2009.  Add in knowledge of the so-called North Atlantic active period beginning ~1995 and one could come up with this number rather painlessly.

[La Nina years:  1950, 1954-6, 1962, 1964, 1967, 1970-1, 1973-5, 1988, 1998-9, 2007-8 and El Nino years:  1951, 1957, 1963, 1965, 1972, 1976-7, 1979, 1982-3, 1986-7, 1991-4, 1997, 2002, 2004, 2006, 2009]

Flashback to October 2007: I posted on Steve McIntyre’s Climate Audit the following:


The North Atlantic was not the only ocean seeing quiet tropical cyclone activity. When using the ACE cyclone energy scale, the Northern Hemisphere as a whole is historically inactive. How inactive? One has to go back to 1977 to find lower levels. Even more astounding, 2007 will be the 4th slowest year in the past half-century (since 1958).

The 2007 Atlantic Hurricane season did not meet the hyperactive expectations of the storm pontificators. This is good news, just like it was last year. With the breathless media coverage prior to the 2006 and 2007 seasons predicting catastrophic swarms of hurricanes potentially enhanced by global warming a la Katrina, there is currently plenty of twisting in the wind to explain away the hyperbolic projections. The predominant refrain mentions something about “being lucky” and having “escaped” the storms, and “just wait for next year”.

And suggested we “Bring out the Broom on the 2007 Season“:

With October nearly done circling the drain, I figure it is about time to bring out the broom: Northern Hemisphere tropical cyclone activity is at historically low levels .

In fact, September 2007 suffered the lowest ACE since 1977 ! Even scarier, so far 2006 and 2007 have the lowest October ACE since 1976 and 1977. And, unnaturally, Sept-Oct 2007 is the lowest since 1977.

Yet, the tropical cyclone season was not shaping up to be such a ghastly bust. For about a week in June, NH ACE was exceeding climatology but then bit the proverbial dust until mid-August when a noticeable comeback ensued. It has been downhill since.

Here’s the Drudge Report screen cap as a refresher of the other news going on (with Hillary Clinton picture goodness):  Forecasters Blow It, Again:  ’07 Hurricane Season may rank as most ‘inactive’ in 30 years


Drudge Report Screen Cap October 2007


And, just for fun, additional screen caps from 2008 and 2009.  Indeed, Matt Drudge mixes up the overall global inactivity with the North Atlantic basin alone.  Regardless, the story is now the same for 4-years in a row:  North Atlantic hurricane forecasts hopelessly overblown against a backdrop of plummeting global tropical cyclone activity overall.

So, I guess it is appropriate to begin the 2011 Atlantic season predictions.  I leave it to Rush Limbaugh, who on Thursday’s program uncorked his highly accurate scheme with help from Roy Spencer:  between 0 and 40 storms.

RUSH ARCHIVE:  I’ll make a prediction.  There will be between zero and 40 storms this year, there will be between zero and 40 to become hurricanes, between zero and 40 that become major hurricanes, and between zero and 40 that impact the United States Gulf or East Coasts, and between zero and 40 who wipe out a city. There you have it.  My prediction is going to be more accurate than anybody else’s.  You wait and see.

RUSH:  That’s my prediction for the 2011 hurricane season. The first out, by the way, with my prediction, and probably a prediction made with more confidence than anybody else’s prediction, which won’t come until next spring.  Again, another shining example of being on the cutting edge.  You learn about everything here first.


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Northern Exposure

Oh, don’t worry… there’ll be an explanation for this from the ‘see-oh-too’ crowd.
Somewhere, somehow, someone said at some point that there would be less storms as global climate disruption grows.
*cough cough*


Heh, I actually happened to be listening when he made the initial forecast for this year and that is quite odd because I probably listen to him for about 15 minutes a month and often that 15 minutes is commercials ( I listen when driving and not often driving during his timeslot).
I had to seriously snicker when I heard it, too, and thought to myself “gee, I wonder if Mr. Watts is catching this one”.
I did notice this year many more days than usual when there was absolutely no tropical storm activity anywhere on the planet and wondered if maybe some analog to the sunspot number could be made. Like the number of tropical storms with a number assignment made based on strength. So maybe an invest low would be a 1, a tropical depression could be a 5, a tropical storm a 10, a cat 1 is a 20, cat 2 is a 30, etc. And you add up all those numbers for all the storms on the planet that day and arrive at an “earthspot” number. It might be interesting to see how a number like that graphs against other things.


It ain’t over ’till the fat lady sings! 2010 could still have some surprises in store.
Until we have a better understanding about all the mechanisms and their relationships, only a Rush Limbaugh 0-40 has real meaning. Something big is missing from our knowledge about storms.

I am still processing data Ryan was so good to point me toward, some of my assumptions were not valid, by spring I should have a much better idea of how next year will be going, [other than “just slower than this year did”.] We shall see next year, meanwhile I still have lots of crow in the freezer to last till then.
Will post updates as I get finished results to base further ideas upon.

Golf Charley

It is great to note how global warming is having such a beneficial affect on reducing destructive weather, as predicted so accurately by the IPCC.
Clearly everything stated by the IPCC is factually correct
High fives, or should that be 10:10’s all round

Latimer Alder

The observations are clearly incorrect. The models have spoken and the intensity and frequency of cyclones must be increasing.
It must be time to remove this version of nature and replace it with one that works the way we would like it to.
Canute (Knut)…by the sea…..England


Who is Rush Limbaugh and why does anyone care?


Tenuc don,t be a sucker the fat lady has stopped singing


It is interesting to note that, even though this has been a ‘La Nina’ season with supposed low wind shear that goes along with that, there has still been quite a bit of shear which prevented some systems from forming & held down alot of those which did manage to get organized. If I recall correctly, the early season systems were sheared by SubTropical jet-oriented shear & later storms by shear from a southward displaced Polar jet which also helped recurve many storms northward while out in the Atlantic (weak Bermuda High).

Bernie McCune

If you had another 30 years of data you could easily see a trend in the North Atlantic ACE 61 Season plot. Since that trend is approximately 60 seasons long it is not as easy to see. And the near term trend (next 10 to 20 years) seems to be downward. It is very chaotic over the short term, but of course that is called weather.


Just a casual engineering observation of data like the decline in the ACE, I would say the Earth is conserving its heat energy.
Could this be a mechanism where the climatic systems are maintaining stable surface temperature in the face of a cooling trend?


Why does everyone keep saying the average number of named storms is 10 when it is 14? Do they do the average between 1979 and 1998 or something?

Colin Aldridge

As I understand it cyclones/hurricanes significantly cool sea surface temperature. Is a historic low ACE number a big enough effect to significantly increase sea surface temperature or more accuartely create a positive sea surface temperature anomaly? “Lack of Hurricanes contribute to global warming… its worse/ better than we thought”?

DJ Meredith

Gloom and doom hurricane predictions may be good fodder for scientific debate, but they’re great for insurance companie’s profit margins. More hurricane alarm equals higher premiums equals higher profits. Just ask the folks in Florida about insurance.
Just ask me about how nicely my AIG stock is doing.


This is a perfect example why the term “climate disruption” is approporiate.
Climate predictions can be easily disrupted by the changing climate.

Joe Lalonde

JoNova is doing a blog on the ARGO not co-operating in giving out it’s data for ocean data.
I guess colder oceans mean less energy stored.

Leon Brozyna

As can be seen here:
the average number (1944-2005) of named North Atlantic storms is ~10, exactly as Ryan wrote above.

The NA ACE looks much like AMO index, or SST record.
While it looks that warmer Atlantic means more cyclone energy, recent record warm Atlantic did not produce anything special. Recent drop either means that NA is cooling (true) and if we insist it is warming as per models, then there is no relation between ACE and SST.


hmmm, i thought that increased CO2 would yield to increased temps would yield to increased tropical activity…so now we are at a 33 year low. just one more thing, in a long list, that global warming adovcates preach about and hasn’t happened(in fact the opposite of what they preached is true)

Wonder if the current local minimum implies that we have another phase-flip in the works, maybe a return to the pre-1976 pattern?

RUSH: That’s my prediction for the 2011 hurricane season. The first out, by the way, with my prediction, and probably a prediction made with more confidence than anybody else’s prediction, which won’t come until next spring.

I believe Klotzbach and Gray will have a first prediction in December. I generally don’t remember it by April when ENSO and other predictors are beginning to firm up.
Two other notes:
1) I’m not pedantic about it, but please consider changing future versions of your first graph to start the Y axis at 0.
2) Someone’s got to put vampire teeth on that photo of Hillary.

Patrick Davis

“Robert says:
October 8, 2010 at 4:40 am”
I believe all those “predictions” about worcening storms with increased C02 concentrations were all based on GCM’s.


I seem to remember an article published about a new paper in some weblog devoted to real science and not the tooth fairy that the low UV this year would result in not a lot of hurricanes in the Gulf. Looks like the model has not been refuted by mother nature. On the other hand the model that says more CO2 makes more hurricanes seems to have been refuted in a rather resounding fashion.


This is, of course, as predicted by AGW theory.

Joe Lalonde says: “JoNova is doing a blog on the ARGO not co-operating in giving out it’s data for ocean data.”
The author of that post apparently missed the fact that, until July of this year, monthly updates of ARGO data had been publicly available through the “Global Marine Argo Atlas” webpage:
They’ve even provided software that allows users to process the data.


Dr Maue –
Great post – thanks v much! But I believe your credibility as a technical arbiter is taken down a few notches with interspersed references to Drudge and Limbaugh. I’d leave the politics out of it – fun for you perhaps, but your technical message might get caught up in “friendly fire”.
Thanks again ….
[ryanm: since I don’t have ready access to the Washington Post op-ed pages e.g. Dr. Mann, I am appreciative of anyone that wishes to disseminate this excellent science news, rather than doom-and-gloom alarmism]

Fools. Everyone knows that global warming makes the weather less predictable. Therefore, every failed prediction proves that global warming is happening. The more inaccurate the predictions from NOAA and the Met Office, the more we can be confident in the theory of global warming. Wake up people!!!

Bill H

as the polar jet increases in size due to the current cooling trend and the equatorial (tropical) jet reduces in size due to the offsetting wind shear it is no surprise the TC is low. the storms do not get enough energy to grow before being ripped apart.
anyone with flying experience knows this…

Bill H

as for proving AGW… Nope.. the pattern is easily observed and repeated. a cooling planet is not a wonderful thing. people starve.. but keep burring your heads in the sand and ignore that which is occurring. i understand it doesn’t meet with the warmers mantra.


I was wondering what had happened to all that hand wringing and Killer storms!


As per average number of named storms, officials have changed the rules to name subtropical storms in 2002 (they get names from regular tropical storm list since)… to get a fair average you must go back and include subtropical storms, as well, back when they recieved numbers or their own names from a seperate list. Oh wait, I bet anyone swallowing the average of “10” never thought about that eh? Really. The average is 14.


Dr Maue
In your work have you come across an indicator that the North Atlantic and North Western Pacific hurricane season not only vary in scale but also vary in storm ‘tracks’ over time? IOW, that the tracks vary from the West and gradualy work their way East over the years, and then move back to the East years later.?
For example, between the years x-x’, the tracks in the Atlantic tend to move primarily in the Gulf; betweey y-y’ they tend to move up Florida’s East Coast; between z-z’ they tend to remain offshore and move up more in the central Atlantic?
Hope you understand what I’m asking;-)


Or, for averaging named storms after the name change (2002-2009), the only other fair thing to do, you would get an average of 15.


When I first ran across RyanM’s graph of ACE about 18 mos ago I used it as a hand around at a believers’ book discussion group, and later asked Chris Mooney when he was going to write ‘Calm World’.
[ryanm: Mooney is too busy with his liberal causes.]


Another take on this. The reason we have cyclones/ hurricanes is due to the energy imbalance created between the warm tropics and the cold polar regions. If there is a decrease in energy differential, then there will be a decrease in the storms necessary to correct this imbalance.
For there to be a decrease in the energy imbalance, then either the “warm” tropics are less warm, the polar regions are less cold, or the transfer mechanism has become disrupted and the energy imbalance is continuing to build at each extreme.
Is my reasoning sound here? Anyone?


Two other old gags of mine are asking the same author when he is going to write ‘The Democrats’ War on Science’ and asking David B. Benson when Spencer Weart is going to write ‘The Discovery of Global Cooling’.

Richard Sharpe

So, the truth is that the warming is in the pipeline, but all the CO2 that humans have released has clogged up the pipeline. This means that the pressure in the pipeline is building up and one day it will explode. If you don’t send more money so we can investigate the clogging of the environmental pipeline, you’ll be sorry!
Also, we are renaming it: Anthropogenic Climate Disruption, or ACD.
We are also investigating the capacity of cultures for climate disruption. This we are calling Anthropogenic Climate Disruption Capacity, or ACDC.
Soon, we will come out with a paper titled: Back in Black, The role of CO2 in ACDC.

It was a balmy 63 degrees at about 90 miles north of Key West this AM … Water temp mid 70s.
We aren’t complaining, but you would think the weathermen are going to have their heads blow off from blowing on every cloud puff that shows up on the satellites … They have gone way past absurd.

Canadian Mike

No doubt the lack of hurricane activity is just as much proof of AGW as greater than average hurricane activity would have been. Gotta love these non-falsifiable scientific theories. Heads I win, tails you lose, let’s increase taxes.


If hurricanes are heat pipes that help regulate global temperature by transporting heat from the surface up into the atmosphere, does a decrease in the number of hurricanes this season mean we should expect increased surface temperatures next season?


I predict reversion to the mean will occur at some point. You read it here first.

Vince Causey

If the tropical cyclone activity has fallen to an unprecedented low, that itself is a climate change disruption.


The global activity is at 33-year lows and at a historical record low where Typhoons form in the Western Pacific.
I’ve found that often the truth is the exact opposite of what the Post Normal Scientists and other Progressives say. This “proves” it! Well, at least according to their logic. “Fossil fuel CO2 quells Cyclones! We’ll never die!” – no charge for this one, but my scientists stand ready…

Ben D.

In all fairness, since temperatures have not gone up in the last five years, their prediction of more hurricanes with global warming is not really disproved, but the entire theory of global warming since its not warming in last 5 years…now that is different (-:
Seasonal variation or normal variation…I think we will find out in the next couple of years. The way they are trumpeting the warmth of an el nino year makes me think they see the fat lady winding up.

Stephen Wilde

“FerdinandAkin says:
October 8, 2010 at 3:26 am
Just a casual engineering observation of data like the decline in the ACE, I would say the Earth is conserving its heat energy.
Could this be a mechanism where the climatic systems are maintaining stable surface temperature in the face of a cooling trend?”
Hi Ferdinand, it sounds suspiciously like you would support me and Joanna Haigh in accepting a reversal of the sign of the solar effect on the stratosphere.
As I said in an earlier thread the quiet sun has sent the polar oscillations way negative to send the jets equatorward. That reduces the spread of the tropical storm regions and gives the storms less space to develop. Even when they do develop they get diverted poleward more quickly and neutered by drier air aloft. Normally that drier air would have been more poleward giving the storms a longer developmental track.
The net effect is indeed to ‘conserve’ energy during the ocean induced cooling spell that we are entering because the quiet sun is resulting in a warmer stratosphere which puts a lid on upward energy transfer from the troposphere by intensifying the inversion at the tropopause.
The real cooling scenario would be negative oceans denying energy to the air at the same time as a more active sun accelerates energy spaceward.
That doesn’t seem to have happened during recorded history so I conclude that coincidentally the solar and oceanic cycles are currently mostly offsetting one another for a relatively stable interglacial climate.
There are short term exceptions but not for long enough to have a serious impact.


Hurricane activity down, despite the impact of manmade CO2 on the atmosphere? Disproves the AGW theory? Hah! You all are so naive, believing that the science matters to the AGW crowd.
I can tell you exactly what their story will be, and its so obvious, that you’ll be ashamed that you didn’t predict it yourself.
They’re going to say (and I don’t believe this by the way) that the global economic downturn has caused a decrease in CO2 and therefore a slowing in climate change.
Therefore the lack of hurricanes proves they’re right.
See? Isn’t that obvious? Sad, yes, but it makes a great soundbite.

RR Kampen

A little is added as TS Otto just achieved minimal hurricane status. But global activity is remarkably low. The Niña pattern would drop Pacific activity, but not per se to record low levels. Surprising.


Tenuc says:
October 8, 2010 at 1:44 am
It ain’t over ’till the fat lady sings! 2010 could still have some surprises in store.

But it’s the hottest ‘year’ on the record. :o)


Time to ask the “Prophet” of the Gaia believers what´s in his brand new PPS. All his predictions failed, so it must have been quite a challenge for his assistants to build up some credible scaring scenarios. His energy bills and his carbon footprint keeps on increasing with no income at sight, Chicago carbon exchange broke, no good prospects unless he is funded by stimulous money.
Really, water levels surrounding him are rising.


It seems that “Climate Disruption” will be disrupted too. Bad luck guys!, better take your surfboards and go to the beach; though now you are too old for that….anyway some mexican pot will make it more endurable.