Saturday, March 15, 2008

Do Tornadoes Indicate Climate Change?

The tornado that hit downtown Atlanta yesterday during the Southeast Conference Basketball Tournament was unusual, but is it a sign of increased tornado activity that might be expected by climate theorists: "more heat into the atmosphere leads to more activity and more violent activity in the atmosphere?" The answer is difficult to discern because any changes over a period of decades could be the result of natural trends. Other alternative hypotheses might be that this just happened to be a one-off tornado of no more significance than that it was an aberration, or that, to stretch things a bit, since downtown Atlanta is somewhat near the ocean, it was really a misidentified waterspout or other ocean-based phenomenon. At the same time, the argument might be made that there is a trend occurring that matches up with increased GHG in the atmosphere. A year or more ago I looked at the data on tornadoes in the United States. It was "apparent to the eye" that there was a trend of increasing numbers of tornadoes, that they were occuring in numbers over an expanding geographical area, and that there was an expanding period of months during each year that constituted the "tornado season."

Now we see a tornado in Atlanta GA, well outside "tornado alley," and we wonder. The article in the New York Times ( indicates that it is not the first tornado in the area, but unfortunately, there is no indication as to whether there were tornadoes prior to 1975.

According to the National Oceanic and Atmospheric Association, the most
recent tornado to hit a major city's downtown was on Aug. 12, 2004, in
Jacksonville, Fla. Downtown tornadoes have also struck Fort Worth, Texas; Salt Lake City; Little Rock, Ark.; and Nashville, Tenn., in the past

If confirmed, the tornado would be the first on record in downtown Atlanta, said Smith, the meteorologist. The last tornado to strike inside the city was in 1975, and it hit the governor's mansion north of
downtown, he said.

I have had the data for more than a year on tornadoes in the United States and will see if I can allocate time to do a statistical analysis to determine whether there is likely to be anything to the climate change theory. If anyone out there would like to participate in the effort, I'd be pleased.

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