It is incredible to me that anyone could treat Senator Kerry seriously at this point, but a credulous media seems to be lapping up his accusations that recent tornadoes represent an increase in such storm activity caused by global warming. 

I am way too tired of refuting this stuff over and over to repeat the whole post I put up a while ago about tornado frequency, but you can find it here.  But here is the short answer for those to tired to click through:  Apparent increases in tornado frequency are an artifact of improved technology that can detect more tornadoes.  If one corrects for this by looking only at tornadoes of the larger sizes (3-5) that were consistently detectable with 1950's technology, there has actually been a small decreasing trend in tornado strikes in the US.

This is drop-dead obvious to anyone who knows anything about weather.  However, since it keeps coming up, the NOAA has an explanation quite similar to mine plastered all over their site.

With increased national doppler radar coverage, increasing population,
and greater attention to tornado reporting, there has been an increase
in the number of tornado reports over the past several decades. This
can create a misleading appearance of an increasing trend in tornado
frequency. To better understand the true variability and trend in
tornado frequency in the US, the total number of strong to violent
tornadoes (F3 to F5 category on the Fujita scale) can be analyzed.
These are the tornadoes that would have likely been reported even
during the decades before Dopplar radar use became widespread and
practices resulted in increasing tornado reports. The bar chart below
indicates there has been little trend in the strongest tornadoes over
the past 55 years.

My daughter when she was 9 years old was able to more accurately portray this fact in a class project than did Mr. Kerry.


  1. Steve:

    Even if you stipulated to the fact that there were more tornadoes, I think it illustrates another point that counters those who want us to cut greenhouse has emissions.

    Adapting is often better than actually stopping the "root cause" of the problem.

    Doppler radar, communications technology, and safe rooms are all likely cheaper solutions to the (supposed) problem of increasing numbers of tornadoes. I'd bet that, controlling for population, the slope of the deaths from tornadoes curve slopes down. If the number of tornadoes is increasing, why might this be?

    Well, I live through one of the worst tornado outbreaks ever (5/3/01) in Norman, OK, and we had a ton of advanced warning that allowed us to seek shelter.

  2. Steve:

    Since I read from top to bottom, I didn't see that Coyote made essentially the same point about increasing hurricanes a few posts down.

  3. Xliberal:

    But that's because JFKerry is so much more interlekshul and more intellijint than Dubya! I find it amusing when the likes of the Goracle and JFKerry, who give scant evidence of having taken many math or science courses when in college, pontificate on such matters for us.

  4. tornadoMaster:

    It appears that tornado frequency began to rise in a big way when world war 1 started.
    It started to go up again just after world war 2 started, but less steep of an increase.
    during the entire period of atmospheric nuclear testing the rate of tornado occurance stayed high.
    They appear to have dropped off somewhat as the environmental movement got going in the 70's
    and was lower around the the time of the first oil embargo.
    aroung 1995, they began to come up again, about the time the Chinese industrial revival really got going. And remember, other old world powers began to ramp up industrial production during the 90's as well.
    Sow the wind, reap the whirlwind.
    pollute the air, cause the tornado.

    of course, the tornado is a natural phenom, that will probably occur no matter what, but we seem to be agravating the situation.