A Flood of Bad Analysis

Notably missing–so far–from the media coverage of the Mississippi River flooding is the usual hand-wringing about how this is surely another sign of global warming. Oh, it’s out there, you just have to look for it in some of the obscure green news sites and blogs. I’ve been predicting for a while now that the mainstream media would grow tired of the climate issue, and it looks as though that time may have arrived. (I noted here last month that Time magazine, which has run more harum-scarum covers on global warming than any other major news magazine, seems finally to have grown weary of the meme.)
One of the many fronts of the climate argument is the cost of weather-related damage, which is assumed to grow worse with a warmer world. I’ll leave aside for today the ferocious argument about whether the U.S. is experiencing an uptrend in extreme weather events like the recent tornadoes (though if you are curious, see Roger Pielke’s blog post on the issue, which concludes: “There is at present no indication that the environmental factors conducive to tornado development for this location and time have changed over the last 30 years, meaning that no change has been detected. Absent detection, there is no attribution”). Let’s just look at one aspect of the issue that comes up frequently: the rising cost of weather-related damage, which is more a function of rising population and a larger built environment than it is trends in weather. One of things Pielke has done is show that if you adjust for population growth and inflation, weather-related costs have not really gone up at all over the last 50 years.
But let’s go one step further. USA Today reported on Friday that one early cost estimate of Mississippi flood damage is $4 billion. This strikes me as quite low, and in any case we won’t know until it is all over. But it is interesting to compare this estimate with the estimates of the annual cost of automobile accidents in the U.S. A 2005 estimate from the Centers for Disease Control puts the cost at $99 billion a year. Other estimates run much higher. A 2008 study from the American Automobile Association puts the annual cost at $164.2 billion, while the U.S. Department of Transportation comes up with an estimate of $230 billion.
By contrast, the UN’s Intergovernmental Panel on Climate Change (IPCC) in 2007 estimated that the total world cost of weather-related damages was $47 billion. Even if the cost doubles, it will still be less than the cost of auto accidents in the U.S. alone. This is not to make light of either flood losses or auto accidents, but it is an interesting contrast that we credit one cost claim (climate) while ignoring a much larger one. But such is always the case when you’re dealing with fanaticism instead of rationality.