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Do Tropical Storms correlate with CO2? In a word — No

Catastrophic killer storms are coming!

‘The Australian Greens say Tropical Cyclone Yasi is a “tragedy of climate change”.’

“DESTRUCTIVE hurricanes such as Katrina and Rita are likely to be more common … Tim Flannery warns.” “These hurricanes have been a catastrophe just waiting to happen.”

The IPCC concludes:

“Studies showed … future tropical cyclones would likely become more severe with greater wind speeds and more intense precipitation.” AR4 Tropical Cyclones (Hurricanes) pp786

Wow, that’s scary! Let’s look at the studies:

“These studies fall into two categories: those with model grid resolutions that only roughly represent some aspects of individual tropical cyclones, and those with model grids of sufficient resolution to reasonably simulate individual tropical cyclones.”

Oh? That’s models, or er… other models?

But where are the observations?

CO2 levels have risen to the highest level in a million years, presumably Hurricanes, Tornadoes and Cyclones are at all time highs, stronger and nastier than we’ve ever seen.

Records of actual tropical storms or proxies for storms show:

  1. Global energy levels haven’t changed since records of that sort of thing began.
  2. Global frequencies haven’t changed either.
  3. Neither Australian or US extreme storms are becoming more common
  4. US Tornadoes are not getting worse either.
  5. Long term studies show it’s not about CO2, and not much about temperature, but more about La Ninas and El Ninos.

Globally tropical storms show no correlation with our CO2 emissions. Their global energy levels are no different to what they were 40 years ago.

Global tropical cyclones accumulated energy

Last 4-decades of Global and Northern Hemisphere Accumulated Cyclone Energy: 24 month running sums through August 31, 2011. 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/blue boxes). The area in between represents the Southern Hemisphere total ACE. Ryan Maue

The Frequency of storms isn’t changing either.

Tropical Storms since 1970

Last 4-decades of Global Tropical Storm and Hurricane frequency -- 12-month running sums. The top time series is the number of TCs that reach at least tropical storm strength (maximum lifetime wind speed exceeds 34-knots). The bottom time series is the number of hurricane strength (64-knots+) TCs. Updated through August 31, 2011. Ryan Maue

See POLICLIMATE for updates and more information.
Global Tropical Cyclone Activity 2011 Activity Updates Ryan N. Maue, PhD

For background information see NOAA: “The deadliest, costliest and most intense United States Hurricanes From 1900 – 2000.” Jarrell, Mayfield, Rappaport and Landsea.

Australian cyclones

According to the BOM, the intensity of tropical cyclones has increased (but it’s not statistically significant) and the total number has decreased. Cyclones in Australia are linked to La Nina’s rather than man-made emissions of CO2.

Australian cyclones total number and intensity BOM

Total number of tropical cyclones (teal bars), and the number of intense tropical cyclones (yellow bars) in the Australian region (105-160E). An intense tropical cyclone is defined by a minimum central pressure of <970 hPa.

US Tornadoes are not getting worse either

Source: NOAA

Tornado number in the US F3 to F5 intensity

The number of strong to violent Tornadoes since 1950 shows little trend.

US Hurricanes 1850 -2006

There is no sign that human emissions make a difference to longer term trends in the US either.

US Hurricane frequency since 1850

Hurricanes USA major per decade 1850 -2006

Major Hurricanes have been striking the US at roughly the same rate for 150 years

The two graphs above come from data from NOAA, and were graphed by Buzzards Bay Natural Estuary Program.

US Hurricanes making landfall since 1850

Number of U.S. landfalling hurricanes from 1851 to 2006 (red bars), the black straight line is the long-term trend, the blue line is the seven-year running mean (from Wang & Lee 2008).

For more information see Marlo Lewis’s excellent article about US hurricanes in 2009.

In the very long term, like 5000 years, storms are not connected to the temperature, except if anything, it was worse in cold times

Fan DaiDu et al looked at proxies (microfossils, sedimentary organic layers, storm deposits, tree rings, stalagmites and corals) and found there was no simple linear relationship between typhoons and temperature over the Holocene period. Basically, it’s about La Nina’s rather than degrees C. More hurricanes and typhoons occur in China, and Central and North America during La Nina years. Even though it was warmer 8000 years ago, the storms weren’t worse.

A few case studies based on geological proxy records show that a warmer climate alone during the Holocene Optimum may not have increased the frequency of intense typhoons. In the last millennium, the frequency of typhoon activity was not found to fluctuate linearly with climatic change over the centennial timescale. On the contrary, typhoon frequency seemed to have increased at least regionally during the coldest phases of the LIA,

Johnathon Nott studied storm surges in North Queensland over the last 5,000 years and found that things have been fairly quiet for the last 200 years compared to the past.

What the longer term records show, however, is that the frequency of extreme cyclones follow a predictable long-scale pattern.

“What the record shows is we go through extended periods, hundreds of years, of high activity and extended periods of little activity,” Nott says.

“The past 100 to 150 years has been very quiet in Queensland in terms of what happened in the past. The couple of hundred years prior to that were very active.”

The Woodruff Thesis also studied a 5,000 year timescale, includes published papers and basically reaches the same conclusion: That big storms depend on the ENSO cycle — La Ninas and El Ninos. They appear to be worse during La Ninas when the sea surface temperature is lower.

Please let me know if anyone finds longer term graphs. I’d like to add them.




Fan DaiDu et al, Perspectives on the linkage between typhoon activity and global warming from recent research advances in paleotempestology Chinese Science Bulletin Volume 53, Number 19, 2907-2922, DOI: 10.1007/s11434-008-0341-2

Klotzbach, P.J. 2006. Trends in global tropical cyclone activity over the past twenty years (1986-2005). Geophysical Research Letters 33 doi: 10.1029/2006GL025881. From 1986 to 2005, there was an increase in hurricane strength (“accumulated cyclone energy”) in the North Atlantic, a decrease in the Northeast Pacific, and not much change in the other four hurricane basins. [For Pat Michaels's review, click here.]

Landsea, C.W. et al. 2005. Hurricanes and global warming. Nature 438: E11-13. Emanuel mishandled data and his methodology is flawed.

Landsea, C.W. et al. 2006. Can we detect trends in extreme tropical cyclones. Science 313: 452-454. The apparent trend towards more powerful hurricanes is a consequence of improved monitoring in recent years of non-landfalling hurricanes. [For Pat Michaels's review, click here.]

Nott1 J. & Hayne2 M. High frequency of ‘super-cyclones’ along the Great Barrier Reef over the past 5,000 years. | Nature 413, 508-512 (4 October 2001) doi:10.1038/35097055;

Swanson, K.L. 2007. Impact of scaling behavior on tropical cyclone intensities. Geophysical Research Letters 34 doi: 10.1029/2007GL030851. There is no statistically significant correlation between sea surface temperatures and average tropical cyclone intensity in either the Atlantic or western Pacific Ocean from 1950 to 2005. [For Pat Michaels's review, click here.]

Wang, C. & Lee, S.K. 2008. Global warming and United States landfalling hurricanes. Geophysical Research Letters 35(1): L02708. Warming of the Atlantic Ocean is associated with an increase in vertical wind shear, which in turn coincides with a “weak but robust” downward trend in U.S. landfalling hurricanes. See the figure below. [For Pat Michael's review, click here.]

Thanks to Baa Humbug for help with this post

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25 comments to Do Tropical Storms correlate with CO2? In a word — No

  • #
    John Brookes

    On the surface, this analysis appears to be correct. Storms appear, if anything, to be decreasing.

    I’m not sure, but I imagine that storms are driven in part by the temperature gradient from the equator to the poles. Thus far, the poles have warmed faster than the equator, so the temperature gradient would be less, and so we might expect fewer/weaker storms.

    I wonder what is expected in the longer term?


  • #

    Hi John,

    About 30 posts ago you were worried that the Swan River was rising as a result of AGW? It was a storm surge over a short period of time that increased tide levels that caused your concern – remember?

    Catastrophic killer storms are coming!

    is garbage and you know it – nothing to do with the poles warming faster and your theory of temperature gradient flux differences from the equator and the poles!


  • #
    John Brookes

    No Dave, it wasn’t a storm surge. And I wasn’t worried about rising sea levels and the Swan River. The variations were on much too short a time scale for it to be due to sea level rise. Anyway, whatever conditions led to the very high tides seem to have abated a little.

    Why do you think the number and total energy of storms are decreasing?


  • #


    No Dave

    Your memory is failing you! Back in May this is the answer to your question!
    May 19th, 2011 at 9:42 pm
    John Brookes at 17

    Several jetties were completely or very nearly underwater a few days ago
    Check out or even BOM website!


  • #

    It’s important to note the word “future” in the IPCC quote. In other words the IPCC has predicted an increase in cyclones, but has not claimed that they have already increased. That does not mean that the IPCC has given the subject a balanced treatment or handled it well. This sums it up:

    I recommend search Roger Pielke Jr’s blog for the phrase “disaster losses” to get an impression of how badly this is being misrepresented by media, “green business” and activists, in contrast to scientific bodies such as the WMO and NOAA. There is even the hilarious, or tragic, fact that the marketing department of Munich Re disagrees with Munich Re’s scientists.

    My explanation for this is that predictions of more or worse disasters in the future are insufficient to make the case that there is a climate crisis to be dealt with urgently, rather than simply a risk or a threat. Thus the seemingly desperate need to make it seem as if “it’s already happening“.


  • #
    john chapman

    G,Day,,,I have walked the land of this great nation for 70 summers…I have witnessed the comings and goings of all manner of weather variation. To me the climate has always been the same alowing for the occasional minor rises and falls…Mother nature will stir the pot as she wishes and puny mankind can do nothing about it…what we have, started at the dawn of time,,,it is with us now and will last untill the sun begins to die and gobbles up our world in the process…Enjoy the ride boys and girls..
    just chatting.J.C.


  • #

    Why does John Brookes comment at #1 have so many thumbs down?
    John makes a valid comment and asks a valid question.

    Come on folks, lets be fair and try to over ride our auto response of giving John a thumbs down to any of his comments. I don’t want to feel guilty every time I whip his ass….EVERY TIME JOHN :)


  • #

    “John makes a valid comment and asks a valid question.”

    It wasn’t a valid question. There is over 150 years of zero evidence that storms are increasing in a warming world. This is absolutely fundamental.

    The alarmist predictions for the future based on models that completely ignore the historical observational data is at the CORE of the current bastardisation of science. History will not look kindly on this whole sorry episode when it is reviewed in the cool light of future days.


  • #

    What a relief when i found this site
    now we can get on with doing somethig constructive.

    You have to be happy about thaqt Jo?


  • #

    The Swan River was waaaay down when I walked around it on Saturday. Lowest I have seen it in months (I walk around it weekly).


  • #
    Kevin Moore

    “A Climate of Confusion”

    BOM cherry picks data.


  • #

    September 7th, 2011 at 12:33 am

    “John makes a valid comment and asks a valid question.”

    It wasn’t a valid question. There is over 150 years of zero evidence that storms are increasing in a warming world. This is absolutely fundamental.

    The question was…“I wonder what is expected in the longer term?”

    Perhaps you can explain why wondering about what the future holds is not a valid question.

    The fact that the past 150 years holds zero evidence that storms are increasing doesn’t mean we know what will happen in the next 150 years.
    First we’d have to determine the relationship between storms and Ts, then we’d have to know what Ts will be in the future. We know neither, which means Johns question “I wonder what is expected in the longer term” is quite valid.

    John provides us with ample opportunities to kick his intellectual butt, however this isn’t one of them.


  • #

    Global Warming and Western North Pacific Typhoon Activity from an Observational Perspective.
    Chan, Johnny C. L.; Liu, Kin Sik
    Journal of Climate, vol. 17, Issue 23, pp.4590-4602

    Based on results from climate model simulations, many researchers have suggested that because of global warming, the sea surface temperature (SST) will likely increase, which will then lead to an increase in the intensity of tropical cyclones (TCs). This paper reports results of a study of the relationship between SST and observed typhoon activity (which is used as a proxy for the intensity of TCs averaged over a season) over the western North Pacific (WNP) for the past 40 yr. The average typhoon activity over a season is found to have no significant relationship with SST in the WNP but increases when the SST over the equatorial eastern Pacific Ocean is above normal. The mean annual typhoon activity is generally higher (lower) during an El Niño (La Niña) year. Such interannual variations of typhoon activity appear to be largely constrained by the large-scale atmospheric factors that are closely related to the El Niño Southern Oscillation (ENSO) phenomenon. These large-scale dynamic and thermodynamic factors include low-level relative vorticity, vertical wind shear, and moist static energy. Such results are shown to be physically consistent with one another and with those from previous studies on the interannual variations of TC activity. The results emphasize the danger of drawing conclusions about future TC intensity based on current climate model simulations that are not designed to make such predictions.

    DOI: 10.1175/3240.1


  • #

    Potential Intensity of Tropical Cyclones: Comparison of Results from Radiosonde and Reanalysis Data.
    Free, Melissa; Bister, Marja; Emanuel, Kerry
    Journal of Climate, vol. 17, Issue 8, pp.1722-1727

    Long-term changes in the intensity of tropical cyclones are of considerable interest because of concern that greenhouse warming may increase storm damage. The potential intensity (PI) of tropical cyclones can be calculated from thermodynamic principles, given the state of the sea surface and atmosphere, and has been shown in earlier studies to give a reasonable estimate of maximum intensity for observed storms. The PI calculated using radiosonde data at 14 tropical island locations shows only small, statistically insignificant trends from 1980 to 1995 and from 1975 to 1995. In the mid-1990s PI at most of these stations does not show the strong increase that appears in global and regional PI calculated from reanalysis data. Comparison with results derived from reanalysis data suggests that previous adjustments to the reanalysis-derived PI may overstate PI after 1980 in some regions in comparison with that before 1980. Both reanalysis and radiosonde PI show similar interannual variability in most regions, much of which appears to be related to ENSO and other changes in SST. Between 1975 and 1980, however, while SSTs rose, PI decreased, illustrating the hazards of predicting changes in hurricane intensity from projected SST changes alone.

    DOI: 10.1175/1520-0442(2004)017<1722:PIOTCC>2.0.CO;2

    As the many peer reviewed literature shows, there is no relationship between a warming world and actual hurricane intensity data nor is there a relationship between a warming world and POTENTIAL INTENSITY data.

    This relationship only exists in the pronouncements of alarmists and activist bloggers who are not really SKEPTICAL SCIENTISTS at all lol :)


  • #

    Significant decline in storminess over southeast Australia since the late 19th century. Australian Meteorological and Oceanographic Journal 61 (2011) 23-30. Lisa V. Alexander, Xiaolan L. Wang, Hui Wan, Blair Trewin

    The appalling litany of IPCC political bollox continues, in spite of the evidence. The blunt truth is that people generally get the administrators, bureaucrats and governments they deserve. More often than not, this is by default inattention. It seems that hope springs eternal and this site is a fount! One hopes that attention is finally building…but then it usually does when the wallet is raided. I sincerely hope that the warmists, IPCC, policy funded scientists, bureaucrats and all the meddlesome folk from the Ministry-of We-Know-Best are individually held to account for this travesty of science and government policy. I tell you, I will not forget nor forgive this colossal extravaganza of stupidity.


  • #

    I’m not trying to kick his intellectual butt …. there’s nothing intellectual about trying to worry people by pondering what the weather is going to do.

    What I massively object to is the emotionalisation of the warmist claptrap. His comment is insidious and if you read the context it actually says ” Sure, I can buy that storms haven’t increased …. but what about tomorrow ? ” Implying that tommorow my be worse than today ! Its an emotional play to human fears in suggesting that something for which there is ZERO observational evidence may still happen. Based on the evidence to date the correct question is “Given that there is no evidence to date, why would we ever assume storms will increase ?”

    The MSM and blogosphere are full of total and utter crap, sometimes directly, and sometimes by inviting people to worry when there is NO REASON. It doesn’t matter whether its drowning atolls, drowning polar bears, spreading malaria, increased flooding, rising sea levels, more storms, a new ice age … whatever …. its just alarmist claptrap, however it is implied, because NONE of it has any basis in the observational record.

    That’s why I object.


  • #

    Government science has been corrupted to the core in the last 40 years.

    I saw it occur over my career, and could not figure out why space scientists were hiding, avoiding and manipulating experimental data until this year, after Climategate revealed the same behavior in climate data.

    For example, isotope data from the 1995 Galileo Jupiter probe – when released in 1998 [1] – confirmed 1975-1983 reports [2-6]:

    The Sun is NOT a steady H-fusion reactor,
    . . . as assumed in SSM (Standard Solar Model) and AGW (Anthropogenic Global Warming) models.


    2. “Elemental and isotopic inhomogeneities in noble gases: The case for local synthesis of the chemical elements”, Trans MO Acad Sci 9, 104-122 (1975)





    Conclusion: The AGW and SSM models are two peas in the propaganda pod that seriously weakened the value of the our scientific, social and economic system.

    These two videos show the transformation from 1961 to 1998:

    President Eisenhower in 1961:

    NASA Administrator Dr. Dan Goldin in 1998:

    I deeply regret that it took 40 years to decipher this puzzle.

    Oliver K. Manuel
    Former NASA Principal
    Investigator for Apollo


  • #
    Mark D.

    I would like to see a current study of peoples PERCEPTIONS of how weather has changed in recent times. The power of suggestion is undeniable and I would bet that the majority of people would agree with the notion that weather has become worse and more dangerous than in the past. Of course they would be wrong but what more important this is an indication of how persuasive propaganda can be.


  • #

    I would like to see a current study of peoples PERCEPTIONS of how weather has changed in recent times.

    Just ask the expert kiddies naturally Mark D.

    As for Australian kiddies worrying more about catastrophic storms they need look no further than the graphical record from 1910 to 2006 for Onslow in WA, the region that cops the worst tropical cyclones in Australia. Notice there’s no increase at all children and big bad Gaia even went to sleep in the 80s. However as lots of your mummies and daddies build more houses together, particularly on the coast and alongside rivers and in flood plains, unfortunately more of them get flooded and damaged, unlike Onslow where mummies and daddies don’t build much.


  • #

    Actually in my day it was all about ‘The Russians are coming to get ya kids!’ and if you saw a sudden big flash you had to curl up in the foetal position behind the monkey bars or some such and kiss yer arse goodbye presumably. To be fair to the oldies at the time they had lived through the Cuban Missile Crisis and the Russkis did have nukes with those annual Moscow Red Square displays, etc.

    Well you can’t have kids growing up without the boogeyman so naturally the current crop of well meaning parents and usual suspects need kids to Shout Out whenever they feel the boogeyman is around the place. It’s a primordial sort of ongoing generational thingy with parents and kids apparently ;)


  • #
    John M

    I’ve often wondered what function of the modelled CO2 induced global warming causes bigger storms?. This has never been explained other than in a throw away line that a warmer world must mean bigger storms.

    Looking at the modelled atmospheric changes, and assuming the models are correct, then an important outcome of more CO2, translates to reduced atmospheric lapse rates as the upper troposphere warms faster than than the surface temperature (ie: upper troposphere hotspot). This is combined with the polar amplification effect, meaning a reduced Temp differental between tropical and polar regions.

    Thus, to the lay person, one would assume that a reduction in the temperature gradients of adjacent air masses would result in an overall reduction in storm intensity and not an increase. This also seems to be in line with actual observed statistics.

    Of course the modelled upper troposphere hotspots are yet to be verified via observation, and serious questions are being asked of these models. But, if you are a true believer in the CO2 mantra then would it not seem more reasonable to be chanting that CO2 leads to a calmer world with smaller and fewer storms ?

    Am I alone with this line of thought ???


  • #
    Mark D.

    John M,

    Your thinking way too rationally. Obviously man is bad and reason doesn’t change that.

    {sarc off}

    IF the poles could warm sufficiently your point would make sense (about less temperature gradient between air masses). However polar temperatures have everything to do with sun angle and nothing [sic] to do with co2. The sun angle (seasonal) isn’t changing because of burning coal therefore I predict the poles will still be cold and especially so during their respective winters, thus we’ll still have plenty of temperature differential

    SO no you are not alone in your thought but your thought points out another failing of AGW theory.


  • #

    John M,

    The usual story we’re told is that warming adds energy to the system, causing stronger storms.

    Your “model” has slightly more detail, so it’s more sophisticated. The models used by climate modelers are still more detailed, obviously. (I don’t know whether the models agree with each other about the effect of warming on storms.)

    The experts I trust most say even this level of detail is nowhere near being sufficient. Averaging over large ares simply cannot capture the dynamics of the situation. So there is no way to know except to observe what actually happens.

    So far any effect is unambiguously small compared to natural variations. So it seems highly unlikely that a few more degrees of warming, if it happens, will have dramatic effects on human civilization.

    So even if you believe the IPCCs projections of warming, there is no indication of “crisis” or “catastrophe”. And, again, even if you believe the projections and AGW theory, CO2 cuts are not a cost-effective way of limiting future storm damage. There are other, far more effective measures. And I believe this is the reason why politicians and activists have such a desperate need to pretend that “it’s already happening” when clearly it isn’t.


  • #

    I’m making a more general point, and let me put this down since it’s just become clearer to me. Climate alarmism is built on the premise of “dangerous climate change”. But the evidence that warming has little effect on disastrous weather events has grown stronger in recent years. And so the evidence that global warming, even 4 or 6 degrees C, could be “dangerous” in any meaningful sense, is weaker than ever. And the most knowledgeable alarmists, such as James Hansen, seem to get this and expand the time frame to hundreds of years, in which major sea level rise is at least theoretically possible. Anyone who thinks it could possibly be meaningful to plan that far ahead can take that seriously. I don’t.


  • #

    [...] dioxide. Neither assumption can be validated by empirical evidence. For one, the frequency of cyclones and tornadoes shows no trend with increasing temperature, let alone CO2. Why does that perception exist, [...]