Tornados and global warming link – "just not there"

We’ve contended many times before that severe weather and global warming are not linked. Here’s a new essay on the issue.

Tornado Hunter
The "Tornado Hunter" from XKCD - click for original

From CO2 Science

Tornados — Summary

Climate alarmists typically claim that global warming will lead to both more frequent and more intense stormy weather; and in terms of their ferocity, tornados rank pretty high on the scale of societal concern. Nevertheless, they have mostly been studied, in this regard, together with several other types of storms, as is the case with the majority of the papers discussed in this summary.

In a major review of “temporal fluctuations in weather and climate extremes that cause economic and human health impacts” — as they titled their study of the subject — Kunkel et al. (1999) analyzed empirical data related to historical trends of several different types of extreme weather events and their societal impacts. This work revealed, in their words, that “most measures of the economic impacts of weather and climate extremes over the past several decades reveal increasing losses.” However, they found that “trends in most related weather and climate extremes do not show comparable increases with time,” suggesting that “increasing losses are primarily due to increasing vulnerability arising from a variety of societal changes, including a growing population in higher risk coastal areas and large cities, more property subject to damage, and lifestyle and demographic changes subjecting lives and property to greater exposure.”

With respect to hurricane losses (which have shown a steady increase with time), the three researchers stated that “when changes in population, inflation, and wealth are considered, there is instead a downward trend [italics added].” They also found that “increasing property losses due to thunderstorm-related phenomena (winds, hail, tornadoes) are explained entirely [italics added] by changes in societal factors.” In addition, they say there has been “no apparent trend in climatic drought frequency” and “no evidence of changes in the frequency of intense heat or cold waves.”

Balling and Cerveny (2003) also reviewed the scientific literature to determine what had been learned about severe storms in the United States during the modern era of greenhouse gas buildup in the atmosphere, paying particular attention to thunderstorms, hail events, intense precipitation, tornadoes, hurricanes and winter storm activity. In doing so, they found that several scientists had identified an increase in heavy precipitation, but that “in other severe storm categories, the trends are downward [italics added],” which, of course, is just the opposite of what climate alarmists contend is the case.

Noting that “media reports in recent years have left the public with the distinct impression that global warming has resulted, and continues to result, in changes in the frequencies and intensities of severe weather events,” which implied changes are mostly for the worse, Hage (2003) attempted to get to the truth of the matter by using “previously unexploited written resources such as daily and weekly newspapers and community histories” to establish a database adequate for determining long-term trends of all destructive windstorms (primarily thunderstorm-based tornadoes and downbursts) in the prairie provinces of Alberta and Saskatchewan in western Canada over the period 1882 to 2001. And because “sampling of small-scale events such as destructive windstorms in the prairie provinces of Canada depends strongly on the human influences of time and space changes in rural settlement patterns,” Hage says that “extensive use was made of Statistics Canada data on farm numbers by census years and census areas, and on farm sizes by census years in attempts to correct for sampling errors.” The results of these operations were stated quite simply: “all intense storms showed no discernible changes in frequency after 1940,” while prior to that time they had actually exhibited minor maxima.

Changnon (2003) investigated trends in both severe weather events and changes in societal and economic factors over the last half of the 20th century in the United States. In doing so, he found that trends in various weather extremes were mixed, noting that “one trend is upwards (heavy rains-floods), others are downward (hail, hurricanes, tornadoes, and severe thunderstorms), and others are unchanging flat trends (winter storms and wind storms).” It should noted, however, that had the analysis of heavy rains-floods been extended back to the beginning of the 20th century, the longer-term behavior of this phenomenon would have been found to be indicative of no net change over the past hundred years, as demonstrated by Kunkel (2003).

So why did insurance losses rise so rapidly over the past several decades? Changnon reports that “the primary reason for the large losses [was] a series of societal shifts (demographic movements, increasing wealth, poor construction practices, population growth, etc.) that collectively had increased society’s vulnerability.” When properly adjusted for societal and economic trends over the past half-century, therefore, monetary loss values associated with damages inflicted by extreme weather events, as Changnon describes the situation, “do not exhibit an upward trend.” Consequently, as he emphasizes, “the adjusted loss values for these extremes [do] not indicate a shift due to global warming.” And to make this point perfectly clear, he reiterates that these real-world observations “do not fit the predictions, based on GCM simulations under a warmer world resulting from increased CO2 levels, that call for weather extremes and storms to increase in frequency and intensity.”

Khandekar (2003) briefly reviewed what he had learned about extreme weather events in Canada in the course of conducting a study of the subject for the government of Alberta. In doing so, he noted how his research had led him to conclude that “extreme weather events such as heat waves, rain storms, tornadoes, winter blizzards, etc., [were] not increasing anywhere in Canada at [that] time.” In addition, he noted that a recent special issue of Natural Hazards (Vol. 29, No. 2) had concluded much the same thing about other parts of the world; and in this context he cited a survey article by Robert Balling that concluded “there is no significant increase in overall severe storm activity (hurricanes, thunderstorms/tornadoes, winter blizzards) across the conterminous United States,” as well as an article by Stanley Changnon, which concluded that “increasing economic loss due to weather extremes in the conterminous United States is a result of societal change and not global warming.”

Focusing solely on tornados, Daoust (2003) catalogued daily tornado frequencies for each county of Missouri (USA) for the period 1950-2002, after which he transformed the results into monthly time series of tornado days for each of the state’s 115 counties, its six climatic divisions, and the entire state. This work revealed the presence of positive trends in tornado-day time series for five of the six climatic divisions of Missouri; however, none of these trends was statistically significant. For the sixth climatic division, on the other hand, the trend was significant; but it was negative. Most importantly, at the level of the entire state, Daoust reported that “for the last 53 years, no long-term trend in tornado days can be found.”

Last of all, Diffenbaugh et al. (2008) briefly reviewed what is known about responses of U.S. tornadoes to rising temperatures. On the theoretical side of the issue, they indicate there are competing ideas with regard to whether tornadoes might become more or less frequent and/or severe as the planet warms. On the observational side, there is also much uncertainty about the matter. They write, for example, that “the number of tornadoes reported in the United States per year has been increasing steadily (~14 per year) over the past half century.” However, they say that “determining whether this is a robust trend in tornado occurrence is difficult,” because “the historical record is both relatively short and non-uniform in space and time.” In addition, the increase in yearly tornado numbers runs parallel with the concurrent increase in the country’s population, which makes for better geographical coverage and more complete (i.e., numerous) observations.

On the other hand, the three researchers report that the number of tornadoes classified as the most damaging (F2-F5 on the Fujita scale) may well have truly decreased over the past five decades (1954-2003), as their frequency of occurrence actually runs counter to the trend of the country’s population. In fact, the graphs they present show yearly F2-F5 tornado numbers in the latter half of the record period dropping to only about half of what they were during the first half of the record, while corresponding data from the U.S. Southern Great Plains show damaging tornado numbers dropping to only about a third of what they were initially. Nevertheless, Diffenbaugh et al. considered the question posed in the title of their paper — Does global warming influence tornado activity? — to be unresolved, stating that “determining the actual background occurrence and trend in tornado activity over recent decades will certainly require further development of other analysis approaches.”

In conclusion, therefore, and in spite of all of the media hype surrounding the rising economic impact of each new year’s weather extremes, there is really nothing unusual about the weather extremes themselves, including tornados. Consequently, since the earth did indeed warm significantly over the 20th century, it must be concluded, on the basis of this empirical evidence, that global warming does not bring about an increase in extreme weather events. Like “the emperor’s new clothes,” which some pretend to see, they’re just not there.


Balling Jr., R.C. and Cerveny, R.S. 2003. Compilation and discussion of trends in severe storms in the United States: Popular perception vs. climate reality. Natural Hazards 29: 103-112.

Changnon, S.A. 2003. Shifting economic impacts from weather extremes in the United States: A result of societal changes, not global warming. Natural Hazards 29: 273-290.

Daoust, M. 2003. An analysis of tornado days in Missouri for the period 1950-2002. Physical Geography 24: 467-487.

Diffenbaugh, N.S., Trapp, R.J. and Brooks, H. 2008. Does global warming influence tornado activity? EOS, Transactions, American Geophysical Union 89: 553-554.

Hage, K. 2003. On destructive Canadian prairie windstorms and severe winters. Natural Hazards 29: 207-228.

Khandekar, L. 2003. Comment on WMO statement on extreme weather events. EOS, Transactions, American Geophysical Union 84: 428.

Kunkel, K.E. 2003. North American trends in extreme precipitation. Natural Hazards 29: 291-305.

Kunkel, K.E., Pielke Jr., R.A. and Changnon, S.A. 1999. Temporal fluctuations in weather and climate extremes that cause economic and human health impacts: A review. Bulletin of the American Meteorological Society 80: 1077-1098.

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Barry Foster
October 28, 2009 1:50 pm

I don’t know how to email Anthony, but has anyone else seen this:
Can someone who has his email post it to him? Cheers.

Henry chance
October 28, 2009 1:57 pm

This is too simple. If people used to buy a 100 thousand dollar house and now it is a 300,000 dollar house they own, if it is wiped out, the insurance claim triples.
Obama mentioned the 10,000 people in greensburg kansas that were killed. The town is well under 2,000 and only less than 12 died. I was there 2 times in the last 3 months. My cousin is on the hospital board. The new hospital replacing the old is worth about 30 million more. Our records on temps are limited before thermomethers and records on storms are not good before video or still cameras.

October 28, 2009 2:25 pm

Is the current decrease in energy/occurance of hurricanes and tornados proof of a flaw in the logic of Globl Warming causing an increase in these storms, or proof of Global Cooling bringing about the opposite effect thereby bolstering the original idea of global warming causing an increase?

October 28, 2009 2:38 pm

Barry Foster (13:50:22) :
I don’t know how to email Anthony, but has anyone else seen this:
I’ve been trying to call people’s attention to this for two days; one or two others have also seen it, but it’s not getting the attention it deserves. I think the expose on how 90% of GHCN temperature recording stations have been dropped as of 2006 sounds extremely relevant to WUWT concerns about skewed temperature trends due to inappropriate siting of thermometers. The international angle is also stunning – how do scientists get away with removing temperature recording sites from the Canadian north (above 62 degrees latitude) and the Australian south? Alexander Humbolt, who started the whole project of world natural parameter measurements (temperatures, geomagnetic force, etc) would be appalled! I would like other people who know a heck of a lot more about this than I do to look at this website and do a bit of peer reviewing of this information.

October 28, 2009 2:56 pm

Speaking of large scale convection patterns and new lines of research.
This just in. There is a really cool video.

October 28, 2009 3:13 pm
Not sure where to put this, but here’s one of our great environmental solutions in action!
Where’s the WWF and Greenpeace now?

October 28, 2009 3:15 pm

The convection roll study has a direct impact on Solar convection. Just wanted to add that.

October 28, 2009 4:00 pm
D Caldwell
October 28, 2009 4:11 pm

Bryan wrote:
“Is the current decrease in energy/occurance of hurricanes and tornados proof of a flaw in the logic of Globl Warming causing an increase in these storms, or proof of Global Cooling bringing about the opposite effect thereby bolstering the original idea of global warming causing an increase?”
Due to our current limited understanding of long-term climate change, interpreting apparent changes of that sort as indicators of either warming or cooling must still be regarded as pure speculation.
The IPCC reports postulate more extreme weather with future warming, but they neglect to properly characterize it as speculative. It would be less alarming that way, don’t you see.

October 28, 2009 4:51 pm

The quality of any statistic is commensurate with the comphrehensiveness of its collection. In 1950, there weren’t dozens of instrumented chase teams swarming every supercell in the midwest. There were no fixed Doppler NEXRAD (WSR-99) radar installations. There were no Doppler on Wheels trucks. There were parts of Tornado Alley that weren’t populated for miles. At that time, the only way a tornado could be counted was if it was observed by law enforcement, public safety or a meteorologist. If one dipped down, tore through an empty field for a few hundred yards and roped out, if no structures were damaged and no one observed the twister, it wasn’t counted.
Collection on tornado frequency statistics is better now than at any time in history. So, of course some alarmists might say that there are more tornados now than before. The truth is more are counted now because the collection is better.

October 28, 2009 4:53 pm

From the IPCC AR4 WG1 Summary for Policymakers:

There is insufficient evidence to determine whether trends exist in the meridional overturning circulation (MOC) of the global ocean or in small-scale phenomena such as tornadoes, hail, lightning and dust-storms.

So, I guess even CO2 Science occasionally does get the science more-or-less correct! (I say “more-or-less” because there is a subtle difference between claiming that the evidence is strong enough to say that global warming does not lead to any increase in tornado frequency or intensity and saying that there is simply insufficient evidence to determine if any trend exists.)

October 28, 2009 5:01 pm

Thanks for this excellent summary of changes caused by “extreme weather”. Clearly there is no AGW involved, although it is very easy to see that human land-use-changes, lowering construction standards, permitting building in sure-to-go-up-in flames or down-in-hurricane areas, pure graft on many governmental levels (as in the levee breaks destroying New Orleans, not Cat 5 Katrina), inflating the money supply by offering junk (debt) as equity, and in general expanding during the warmth of a warm period. We will learn many lessons in the cold period certain to follow.
There are three individuals I am most certain deserve a three-way Nobel-type prize for their dogged pursuit of the lies, obfuscation, and probably downright fraud in climate pseudo-science of AGW-CO2 demonization.
First is our own Anthony Watts for finding that there are few accurate and appropriately sited surface thermometers to give us a regional average temperature, or a “global temperature”. In my experience he really got the investigative ball rolling and showed everyone what is possible when you follow your instincts and your good sense. And he developed a blog that surpasses all others in attracting readers from around the world to a wide variety of climate issues. Intelligent, funny, and pointed.
Second is Steve McIntyre, the dedicated scientist who says that every study making important claims leading to policy changes better have accurate data and appropriate methods — and he reruns the studies himself, that is, after he can pry the data from the clutches of these depraved pseudo-scientists. Most of the AGW studies are phony, not worth the paper they are printed on. Please read Climate Audit every day — especially follow the Briffa exchanges.
Third is E.M. Smith. In his wide ranging intelligent blog he has been tracking down every thermometer in the world from the GISTemp data base (I think). Barry Foster mentions Mr. Smith in the first comment. This information is ready to rock the climate world. We could hardly imagine how nefarious our so-called public servants and the academic science-priesthood are if his findings are accurate. He is calling for help to run his (their) computer programs again to check the astonishing results. IN THE LAST FEW YEARS THEY HAVE DROPPED HUNDREDS (OR THOUSANDS) OF THERMOMETERS THAT DO NOT SHOW WARMTH. For example, since 2007 California has only three, yes, 3, for the entire state and only in the urban beach areas. Are they helping the UN and Barry O prepare for the takeover of Copenhagen? Take a look —

October 28, 2009 5:17 pm

vigilantfish (14:38:12) : I’ve been trying to call people’s attention to this for two days; one or two others have also seen it, but it’s not getting the attention it deserves I think the expose on how 90% of GHCN temperature recording stations have been dropped as of 2006 sounds extremely relevant to WUWT concerns about skewed temperature trends due to inappropriate siting of thermometers.
FWIW, the page you cited was the first broad cut. This page:
In particular looks at the USA data set. That ought to be exactly what Anthony would be interested in. Basically it shows that of all the stations that looks at, 136 make it into GIStemp.

October 28, 2009 5:30 pm

The big issue I see with the “AGW causes tornadoes” and similar theories is that they try to “hold all else equal”, yet all else is NOT equal.
We had a change of atmospheric thickness after the sun went quite.
Who allowed for that in their tornado theories and hurricane theories?
The wind has had a very blustery quality that I last remember from 40+ years ago (and I’ve got a limb down in my yard today.. ) that I think is a direct result of this “surprise”.
Between the raw data being unavailable or molested beyond belief, the code for analysis being dodgy at best, and the theory missing things as big as the atmospheric thickness; I’m beginning to doubt that the folks we employ as “experts” in this stuff have any clue at all how to do the work expected of them. “Science as Media Event” seems to be the major driver of publication for many of them. IMHO, of course.

John M
October 28, 2009 5:51 pm

It’s far more nuanced than that.
Global warming actually causers fewer tornadoes, so yuh see, fewer tornadoes are not inconsistent with climate change.

October 28, 2009 6:23 pm

The thing I get out of seeing the tornado destruction scenes is that trailers and mobile homes all crowded together are prime tornado targets.
That, and they are no match for your average twister.
Where’s the storm cellars?

October 28, 2009 6:26 pm

There’s an article in the Oct 27 Globe and Mail (Toronto) titled: “Worsening weather, climate change whip up insurance woes”. It tells a totally different story, of course. (I couldn’t locate the story on their website, so no URL. Sorry.)

Eric (skeptic)
October 28, 2009 6:56 pm

Joel, it sounds like the IPCC hasn’t figured out a way to hockey stick the tornado statistics. Occasionally even they get something right.

October 28, 2009 6:57 pm

Ecochemist (15:13:55)
OT, but that will never be reported unless its a bunch of ducks in a tailings pond…

October 28, 2009 7:03 pm

Global warming actually causers fewer tornadoes, so yuh see, fewer tornadoes are not inconsistent with climate change.
Indeed. Decreasing tornado frequency and severity is reasonably good evidence that global warming is actually occurring. Whether this warming is AGW is another question entirely.
However, to admit that many, if not most, consequences of GW are benign or beneficial in terms of the weather undermines the case for the need to ‘act’ on GW.

Gregg E.
October 28, 2009 7:47 pm

Who saw “Twister” and the knockoff copy “Tornado” starring Bruce “If Chins Could Kill” Campbell?
In both movies, teams of storm chasers attempt to place sensor devices in the path of a tornado in order to get a swarm of them sucked up into the funnel cloud.
In the real world, some storm chasers have been attempting a similar feat, but with the equipment staying (hopefully) on the ground.
Here’s my idea for a sure-fire method of injecting things into a tornado. Replace the warhead on a TOW missile then fire it into the storm.
The payload could be anything from active sensor devices transmitting data to pieces of radar reflective chaff. Make the chaff pieces all the same size and it’d be simpler to calculate exact wind speeds using doppler radar.
Without knowing in advance the size of raindrops and debris, along with the exact radar reflectivity of debris, there’s some uncertainty in speed calculations.
Firing in some “calibrated debris” that’s too lightweight to cause any damage would be a very useful addition to the toolbox of meteorologists.
Taking this to the next level – finding out if it’s possible to disrupt or weaken tornadoes of various sizes with various sizes of explosives, detonated in different parts of the funnel clouds.

October 28, 2009 8:01 pm

Case in point….the infamous Tri-State Tornado in 1925:
It was the most long-lived (its track was an incredible 219 miles) ever recorded in the world, and the deadliest tornado disaster in the USA.
Eyewitnesses report not seeing a funnel, but a boiling fog that covered the horizon.
That was 1925. [AGW back then was real strong, you see.]
And yet THIS year’s tornado season? Just like the hurricane season for the Atlantic.
Rather boring and non-eventful.
Well….at more CO2 ppm than ever (and definitely more than 1925) and heading toward the tipping point…this “stormchaser’s hell”…must be caused by AGW too.
Hmmm. Something’s fishy.
Why doesn’t “fraud” cover…..??
They try pyramid-sheme scam artists when they dupe out people…and PROFIT off of the process.
Bank execs and Enron execs are tried when they squander the public trust.
Al Gore should be tried.
Norfolk, VA, USA

October 28, 2009 8:13 pm

Offtopic tipsters – aim your tips toward that “Tips” link at the top of the page.
Anthony – Your image additions are often interesting. This XKCD image rates a +F3. E? I don’t do E.

October 28, 2009 8:46 pm

@ vigilantfish (14:38:12)
For many years Environment Canada and NAV Canada/Transport Canada have been reducing the numbers of live weather observation stations and flight service stations respectively. Some have been replaced by automated stations, which definitely have their limitations. It would be interesting to see what raw data might still exist for the Far North.

October 28, 2009 9:07 pm

Barry Foster
Is there a list of global stations that is used by GIStemp to calculate earth’s av temperature and where is it accessible?

October 28, 2009 9:10 pm

Alittle problem with firing TOW missiles into storms. When the rocket motor uses up it’s fuel, the missile falls to earth, somewhere.

Barry Foster
October 29, 2009 1:33 am

kasphar, this is all I have:
But if you click on the map anywhere it will take you to the list of stations in that area (and if you click on the station names you’ll get the graphs). However, you’ll see that very few stations are up to date.

Barry Foster
October 29, 2009 1:59 am

kasphar. The stations actually used and their geographical location:

Alan D. McIntire
October 29, 2009 6:43 am

Give the scenario a little thought, and you’ll realize that an increase in hurricanes and tornados would also imply an increase in CLOUDINESS. An average of 342 watts hits the earth, but only about 240 watts heats the earth, the 102 watt balance is reflected away by clouds. Increase the clouds, and you’ll also decrease the fraction of solar heat warming the earth- a negative feedback.
Also consider that no specific percentages for the increase of storms is given, and you’ll come to the conclusion that the whole idea of increased tornado and hurricane frequency due to global warming comes off as a not very convincing halloween ghost story.

October 29, 2009 6:45 am

A couple of sites relevant to the main topic.
1. Ryan Maue’s cyclone energy index from 1979 to the present shows that activity peaked in the early 1990s and again about 2005 but is now lower than any time in the past. Given the period he covers corresponds to the period satellites were used to estimate cyclonic activity it is easy to see how people could have believed that increasing temperatures were leading to increased activity.
2. At the climatedata .info site there is an analysis of storms which made landfall in the USA since 1850. This has a similar form to Ryan’s Northern Hemisphere index for the last 30 years but shows that these years had less activity than almost the whole of the last century and a half.

Sophistry in politics
October 29, 2009 10:42 am

Forget about average global temperatures. Forget about ice caps melting and Polar Bears floating across the Atlantic on ice cubes. Forget about rising sea levels, droughts, increased hurricanes, floods and on and on. Also forget about sunspot cycles or El-Nino and La-Nina, or whatever the hell else has been thrown into the mix as a distraction because none of it matters, none of it is relevant. All we have to do is drill down and focus on one thing only.
That one thing is CO2.
It is claimed that humans are responsible for Climate Change because of our CO2 emissions and that we need to have limits imposed because we need to reduce our emissions of CO2.
So first simply ask yourself this:
Can CO2 trap in heat?
Answer: NO, nothing traps in heat, substances can only absorb and re-emit heat but they cannot trap heat.
Next question, does CO2 absorb heat more strongly than the other gasses in the atmosphere?
Answer: NO, CO2 is only 0.03811% of the atmosphere and remains as solid ice up to a temperature of 194.65 K
Nitrogen and Oxygen which make up 99% of the atmosphere on the other hand, begin to melt at temperatures as low as 50-60 K and so are much stronger absorbers of heat and at the same time, make up most of the atmospheric gasses.
This puts the effect of CO2 into context. CO2 cannot trap heat as no gasses in the atmosphere can. CO2 is a tiny proportion of the gasses in the atmosphere, so tiny in fact that compared to Oxygen and Nitrogen it is barely noticeable. The effect of such tiny amounts of CO2 being a much weaker absorber of heat than Nitrogen and Oxygen, also show that the warming effect of CO2 is insignificant.
So the final question is, are we responsible for Climate Change through our CO2 emissions?
Take that to Copenhagen!
If you would like to know more about the AGW fraud and carbon tax, download this free .pdf book

October 29, 2009 1:45 pm

Thanks for the link, Barry.
It would be interesting (for comparison) to have a list of stations used before 1990 when many stations were dropped off. I suppose Chiefio has done most of the hard yards.

October 30, 2009 10:39 am

Article on Piers Corbyn’s stuff at the BBC. Not found and better detail elsewhere.

October 30, 2009 10:42 am

Sorry, not sure what went wrong with that. Here it is again.
Piers Corbyn Article at BBC

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