While claims of increased severe weather due to “climate change” aka “global warming” are thrown about by the media, with recent claims that more and more tornadoes are shifting east in the U.S., the fact of the matter is that the trend for strong tornadoes is decidedly down, according to data from NOAA. The US is on track to have the lowest annual tornado count in 65 years.
h/t to Mark J. Perry, AEI for the graph.
We recently covered the lack of tornadoes in 2018 from data supplied by the NOAA Storm Prediction Center, but the above graph clearly illustrates the downward trend. from 1954 to 1985, there was an average of 55.9 F3 strength or greater tornadoes in the USA per year, and in the period from 1985 to present, that number dwindled to 33.8 F3 strength of greater tornadoes per year. The year isn’t over yet, but now that we are out of the main period of tornado activity, it’s a likely bet that 2018 will come in the lowest ever.
For those not familiar, here is the original Fujita tornado strength scale, which is accepted as a world-wide metric by NOAA and the WMO:
Since “global warming” is said to be the cause of the perception of increased violent weather, taking a look at temperature for the USA during the same period should yield a correlation.
This comparison graph I prepared, showing USA temperatures from 1954 to 2018, illustrates the correlation between tornadoes and temperature is exactly opposite of what we are being told by climate advocates.
See below for this comparison graph I made, showing USA temperatures from 1954 to 2018, illustrates the correlation is exactly opposite of what we are being told by climate advocates. Again the source of the data is NOAA, using their “climate at a glance” plotter. I’ve shaded the 1954 to 1985 period of temperature to match the shaded 1954 to 1985 period in the tornado count graph,but otherwise both graphs are original:
Source of temperature plot (and data) is here.
Source of Tornado data is here
Breaking down the two periods, the NOAA “climate at a glance” plotter provides the 1954 to 1985 trend, when there were the most violent F3 or greater tornado counts in the USA:
Source of plot (and data) is here.
Shockingly, from 1954 to 1985, when violent F3 or greater tornadoes were most common in the U.S., there was a cooling trend of -0.13°F per decade.
But let’s look at the 1985 to 2017 (2018 is not complete yet) trend, when there were fewer violent F3 or greater tornadoes:
Source of plot (and data) is here.
In the 1985 to 2017 period, there was a warming trend of +0.48°F per decade.
Clearly, warmer climatic periods yield fewer violent F3 or greater tornadoes in the United States. And that blows a hole in any warming correlation that advocates like to claim for increasing numbers of severe tornadoes.
Oh, and remember the story about tornado paths shifting east?
This map illustrates that in the larger scheme of things, even if the claim holds true, most tornadoes in the USA are in the east anyway, and the difference really isn’t that significant when you look at where the majority of U.S. tornadoes occur:
Source: NASA Earth Observatory
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Coincidence! I plot quite resently this:
Red are “light” tornadoes (F<3) and blue are "heavy" tornadoes (F=3,4,5)
Risto,
That could be an artifact of our increasing ability to detect lesser tornadoes, which occur away from populated areas and inflict no damage, ie little better than dust devils.
exactly , look at what I’ve already posted about that.
>EF3 are consistent . It is the recording ofsmall events which is not. That is used as an excuse to throw out all discussion of the “inconvenient” tornado data, by folks with an agenda.
Unless there is some remote sensing out there that I’m not aware of, the detection of tornadoes is not that great or accurate. If an EF3 never touches the ground, is it really a tornado? I don’t think Doppler Radar can tell you whether a tornado actually touches down and it sure can’t tell you about the damage down on the ground. Can it tell you the speed while on the ground or just aloft? Damage assessment takes eyes. You do know that there are areas out here on the Great Plains that aren’t even covered by Doppler Radar?
Jim,
My point is that we now have the ability to detect more small or near-tornadoes than, say, in the 1930s. It wasn’t that our detection capabilities now are perfect.
As I pointed out above, does a tornado have to reach the ground? If so, can doppler tell you if a tornado reaches the ground and what damage is done? Do ‘near’ tornadoes count as tornadoes. This whole mess is a subjective mess of interpretations. If remote sensing is so accurate, why do storm chasers still have jobs. Why do tv stations still dispatch video teams?
Jim Gorman,
The Doppler radar gives video teams a location to check out.
Doppler was the main reason for the surge in smaller event detection. It is hard to suggest that a drop in the number of tornadoes recorded was due to increased surveillance or immporved techniques.
Since the records of EF3 EF4 and EF5 all show a consistent DROP in tornadoes, how is this an issue?
Greg,
The data show a marked increase in less powerful tornadoes, and a drop in the more powerful ones.
… and that increase in small events may be totally spurious anyway. That is the part of the data which is unreliable and needs to be rejected when looking for long term change.
Throwing the baby out with the bathwater is a trick being used by those who don’t like the look of the baby.
Sorry.
Soon the snow cover in eastern Canada will increase significantly.
https://www.tropicaltidbits.com/sat/satlooper.php?region=atlpac-wide&product=wv-mid
Let’s see what the IPCC says about US tornadoes.
“Severe thunderstorms, associated with large hail, high winds, and tornadoes, are another example of extreme weather associated with the water cycle. The large-scale environments in which they occur are characterized by large Convective Available Potential Energy (CAPE) and deep tropospheric wind shear (Brooks et al., 2003; Brooks, 2009). Del Genio et al. (2007), Trapp et al. (2007, 2009), and Van Klooster and Roebber (2009) found a general increase in the energy and decrease in the shear terms from the late 20th century to the late 21st century over the USA using a variety of regional model simulations embedded in global model SRES scenario simulations. The relative change between these two competing factors would tend to favour more environments that would support severe thunderstorms, providing storms are initiated. Trapp et al. (2009), for example, found an increase in favourable thunderstorm conditions for all regions of the USA east of the Rocky Mountains. Large variability in both the energy and shear terms means that statistical significance is not reached until late in the 21st century under high forcing scenarios. One way of assessing the possibility of a change in the frequency of future thunderstorms is to look at historical records of observed tornado, hail and wind occurrence with respect to the environmental conditions (Brooks, 2013). This indicates that an increase in the fraction of severe thunderstorms containing non-tornadic winds would be consistent with the model projections of increased energy and decreased shear, but there has not been enough research to make a firm conclusion regarding future changes in frequency or magnitude.”
IPCC WG1 Ch. 12, p1087
Looks like the IPCC is off the hook. So who has been promising more tornadoes?
“… is not reached until late in the 21st century under high forcing scenarios.”
so not really off the hook. That is sufficient for MSM to claim that the IPCC anticipates more tornadoes “in a warming world”.
We
muddledmodeled along until the results matched the party line.The MSM is not the IPCC. Journos are not scientists. Distinctions are important. The observation that the MSM sensationalizes stuff is so banal it is sleep-inducing. Mixing up provenances just adds to the confusion, and there is plenty enough mixing up what the weight of scientific opinion says, with what activists or journos say.
The problem is that other “scientists” such as biologists, chemists, sociologists, etc. (my colleagues at work for example) don’t do due diligence and believe the MSM and the information coming out of a variety of scientific, conservation, and environmental groups to which they may belong. And the IPCC summary for policy makers often exaggerates or gets things wrong as well and the MSM and scientific bodies (used broadly as the WWF for example has many scientists as members) take that at face value. So there is a reason to try to correct misperceptions when these are in the media daily and become part of political platforms and suggested laws.
many climate scientists are actually political activists now, and are quite happy to be complicit in providing jounros with “expert testimony” that goes way beyond what they could get away with in a paper.
Trying to marry what you said with my comment.
Are you saying we should not make distinction between what the weight of scientific opinion says and what journos and activists say?
I prefer to report the science when activists and journos muddy the waters. Hence the quote starting this subthread.
Do you prefer to report the science (weight of opinion + uncertainty and maybe outliers), as a platform from which to judge all commentary on it? Or do you have a different approach?
Mr Mosher always makes the same mistake, he thinks I write with his specific (and often cryptic) expectations in mind.