‘On climate time scales there is no indication of increasing incidence of tornadoes…’

Dr. Roger Pielke Jr. points out a new paper for which he is a co-author.

Normalized Tornado Damage in the United States: 1950-2011

in press, Environmental Hazards

Kevin M. Simmons, Daniel Sutter and Roger Pielke, Jr.

In this case, a picture is worth a thousand words: 

Normalized Tornado Damage 1950-2011

  • Overall we find a decrease in damages since 1950.
  • Even so 2011 was one of the 3 most costly years in our dataset.
  • Our dataset includes 56,457 tornadoes, of which 33,746 caused some recorded damage.
  • Since 1950, in round numbers, tornadoes resulted in about half the normalized damage as did hurricanes and twice that of earthquakes
  • The strongest two categories of tornadoes (called EF4 and EF5) represent about 1% of all reported events but have caused almost 45% of all normalized damage.
  • The most damage per square mile from1950-2011 has occurred in Massachusetts and Connecticut.
  • The most damage overall  from 1950-2011 has occurred in Texas and Alabama.
  • During the calendar year 80% of damage occurs January-June.
  • The most damaging months are April (31%), May (20%) and June (16%).

He writes:

On climate time scales there is no indication of increasing incidence of tornadoes, and the increases documented over the short (sub-climate) period 2000-2011 are strongly influenced by the large number of events documented in 2011. However, the decreased frequency of high damage events in recent decades as compared to previous decades is a notable feature in the time series and provides strong counter-evidence to claims found in the scientific literature that the atmospheric environment that spawns tornadoes has intensified leading to more intense events on climate time scales (e.g., Trenberth, 2012). Such claims are commonly found in the popular media and also in the insurance/reinsurance sector where they influence public opinion and decision making in business and government. The most recent review by the IPCC found no basis for claiming an increase (or decrease) in tornado incidence or intensity (IPCC, 2012).”

Read his full essay here

About these ads

12 thoughts on “‘On climate time scales there is no indication of increasing incidence of tornadoes…’

  1. ‘On climate time scales there is no indication of increasing incidence of anything unusual at all…’

    Thought I would expand the posts title to cover the rest.

  2. Muller said that in one of his public audience Physics for Future Presidents talks a few years ago as well, i.e. no inflation adjusted increase in damage.

  3. So we have weather.
    Does weather tip people off gravy trains? Enough of it may do just that.
    Climate varies – and we don’t know why – there are a host of suspects, most, or all, involved – plus the ‘unknown unknowns’.
    CO2 may force – or maybe a laging indicator [or a bit of both]; and we don’t know. Do we?
    We have some good ideas on some of the factors, but I’m not sure that there is any we fully understand, except, maybe, the Gas Laws. Do we even understand all the implications and interactions of those fundamental physical laws?

  4. Looks like the chart left off the last digit in the year number.
    Either that, or they’ve got some good tornado stats from Emperor Septimius Severus.

    Png’s and gif’s are better than jpeg’s for charts.

  5. I gave up trying to post on Roger’s site. Here is what I was trying to say.

    I reread the following sentence several times and could not figure out what it meant:
    “To emphasize, we do not reach any conclusion here that stronger that “suggestive” and recommend that this possibility be subject to further research, which goes beyond the scope of this study.”

    IanM

  6. The most recent review by the IPCC found no basis for claiming an increase (or decrease) in tornado incidence or intensity (IPCC, 2012).”
    ———
    I haven’t read the full essay. Maybe I should. But my eyeometer says the graph is showing a downward trend. A downward trend does not correspond to any explanation that I am aware of. I am a teensy bit suspicious that Roger has been a bit too enthusiastic with his “normalization” process.

  7. Gunga Din on October 8, 2012 at 12:38 pm
    The last digit of the “year” on the scale is missing.
    ——-
    That gave me pause as well, but it’s just compact representation of a decade worth of years and the reader is supposed to fill in the missing 0 1 2 3 4 5 6 7 8 9 for themselves.

  8. Lazy says:

    “A downward trend does not correspond to any explanation that I am aware of.”

    Translation:

    “I got nothin’.”

  9. “A downward trend does not correspond to any explanation that I am aware of.”

    Well, LT…I guess you haven’t been listening. The idea that a reduction of the temperature gradient from the poles to the equator (AGW) would produce more severe storms, makes every meteorologist turn down the road towards skepticism. It is just plan wrong and the above results are exactly what we would expect if the poles where getting warmer by a larger degree than the equator.

    If the planet had a uniform temperature from pole to pole, there would be almost no severe weather anywhere. Make the poles colder and the equator warmer, and the mid-latitudes would become a meteorological Armageddon. This is meteorology 101…probably in the first week or two of class.

    When the IPCC starts claiming that a more uniform global temperature will lead to more severe weather, graduates of meteorology 101 know that someone is running a scam.

    If you are unaware of this explanation, perhaps you would benefit from reading a science book on the atmosphere instead of the propaganda that is keeping you in the dark.

  10. I think there is a confounding of two things. “More frequent and intense storms” (tropical storms cyclones and hurricanes) gets mixed up with tornadoes.

    cyclones are driven by sea surface temperature. There is a link in the data. Both AMO and cyclone energy show that the dramatic increase of the 90s is over and we’ve probably passed the peak.

    Tornadoes are caused by wind shear. From what I have seen here on WUWT that is more likely to occur during periods of global cooling.

    Pielke Jr’s latest graph would seem to corroborate that, showing much more activity in the post-war cooling period, less activity since mid 80s and a new blip in the last decade.

    Yet another climate index, for those who are still in denial, that we are entering a period of global cooling.

Comments are closed.