Wednesday, March 21, 2012

Are Tornadoes Getting Stronger Due to Global Warming?

There was very recently a story in the national media asking whether tornadoes have gotten stronger due to 'global warming.' The answer is "no" for two reasons:

  1. Global warming is not currently occurring and hasn't for a decade and a half.

  2. If anything, there is a downward trend in number of violent tornadoes. 

Let's start with #1.  

Here is the current chart of temperatures versus the long-term normal (vertical scale) as computed by the (pro-global warming) Hadley Center in Great Britain covering the last 15 years. There is no warming trend.

You cannot have stronger tornadoes in the last two years due to global warming if temperatures were cooling during that period. Note: I do not make any prediction as to future temperature trends. I don't know nor does anyone else. 

Second, there simply is no upward trend in violent (F-3 to F-5 intensity) tornadoes. Here is the official data from the National Oceanic and Atmospheric Administration.

If anything, total numbers of intense tornadoes has lessened during the latter half of the period. However, because there are measurement issues plus the F-scale does not truly reflect tornado intensity (it reflects tornado damage, thus a strong tornado in a wheat field gets under-classified), all I'm willing to conclude is there is no upward trend.

So, the question is answered. At the present time there is no upward trend in tornado intensity due to global warming.  

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