Thursday, May 26, 2011

Some Years It's Just Windy

Bill McKibben credits climate change for the recent series of tornadoes decimating the Mid-West. This might be climate change related. On the other hand, it might just be random. I don't have the background to answer this question definitively, but nerdy curiosity led me to gather some data from the Tornado History Project.

THP keeps track of every single recorded tornado in the United States since 1950: where it was, its intensity, and even the path it took. I gathered tornado data from the past sixty years to see if the number of tornadoes have been trending upward.

"But wait!" you might say, "What if the number of tornadoes is the same but they are getting more intense? You can't just look at the number of tornadoes." Indeed I cannot. The way THP records tornado intensity is with the Fujita scale, ranging from F0 (min 40 mph) and F5 (min 261 mph). So I created an alternative time series of total tornadoes weighted by intensity. Admittedly, this approach is very simple but sufficient. Each F0 counts as one tornado; F1s each count as 2 two tornadoes, etc. Then I added them together. For example, in 1955 there were 116 F0s, 200 F1s, 163 F2s, 29 F3s, 8 F4s, and 2 F5s, or 518 total tornadoes and 1,173 weighted tornadoes. Below is the graph Excel spit out for me:

There's a pretty clear upward trend in that diagram, consistent with concerns over global warming. BUT this is assuming that we're just as good detecting tornadoes today as we were in the 1950s. If an F5 came through, I doubt that would get past anyone's radar regardless of where it touched down. But an F1 or F0 (i.e. the ones that are barely tornadoes) could slip past undetected without satellite imagery or other modern equipment. So what do the graphs look like without the small tornadoes? Much less frightening. Here's total tornadoes only counting at various thresholds of intensity:

And here's weighted tornadoes with the same thresholds:

The F0s seems to be doing most of the work, which does not fit with the global warming story. For completeness, here's the F0s over time. Most of the jump occurs in the early 1990s; I'm not sure why.

Again, this doesn't mean that the GW explanation isn't true, but it doesn't suggest it either. This data tells us that tornado activity varies widely. The ten-year low for all intensities is 934 tornadoes (2002) and the high is almost twice that: 1817 (2004, just two years later!).

Wednesday, May 25, 2011

Local Taxes Should Go To Flower Gardens Instead of Schools

I got into a short discussion the other day about taxes to fund local schools. A friend complained about individuals who resent paying such taxes when they have no kids. "Well, shouldn't they resent that?" I asked. "No," he said and argued that education is a public good. We all benefit when more people go to school.

There's a long list of things wrong about this claim.

  1. A public good does not mean "good for the public." It has a very specific definition: a good where you usually can't exclude people from using and each additional user doesn't diminish the value of the good. National defense is an example. Education is not.

  2. Even if there are some social benefits to education, the gains from education are largely internalized. If local funding for schools dried up tomorrow, schooling would not cease, not by a long shot. Parents would pay for their kids to go to school. They already do, even though they are also paying for it through taxes. Schooling's so important, they pay for it twice.

  3. Private education is not strictly for the wealthy. In the poorest parts of the world, the poorest people pay to send their kids to privately run schools.

  4. Even if the social value of education is high, it also had a negative value. Education (especially higher education) is great for demonstrating intelligence, hard work, and other qualities difficult to observe. Having a high school or college degree shows employers you have those qualities. But when everyone has a degree, then employers can't tell the smarties from the stoners. A dumb person's degree pollutes the value of a smart person's degree.

  5. Somewhat related, the whole notion of tying education to where you live is bizarre and a recipe for ineptness. Imagine that all haircuts were free, that barbers were paid with local taxes, that legal restrictions made it difficult/impossible to establish new barber shops, and that you could only get your hair cut within a 5 mile radius of where you work.

It is far more logical to send those taxes dollars to flower gardens. These gardens are a public good (it's impractical to exclude people from viewing them, assuming they are in the front yard or other public space; and me enjoying the flowers doesn't prevent you from enjoying them...unless you pick them). The social benefits are high (the person maintaining them receives just a small fraction of the total enjoyment they create), the social costs are low (all I can think of is allergies, and that's a very small addition considering what's already there). And since it's non-excludable, you can't tie a community to a pre-approved set of flower gardens.

Sunday, May 01, 2011

False Dichotomy

Talk about why the price of oil is raising now seems to be framed as a mixture of genuine supply and demand forces and of speculators causing the price to raise. First, let me joyfully acknowledge that supply and demand are not being seriously considered by mainstream media--a definite improvement over previous discussions which focused on "how greedy/evil are oil companies?" But the current debate isn't much of an improvement.

Asking how much of the increase is due to supply and demand and how much is due to speculation is like asking "is my car not running because there's something wrong with it or because the engine's broken?" One is a subset of the other. Speculators, like other economic actors, respond to supply and demand forces. The only difference between them and us is that they are responding to future supply and demand. But it's still all about the fundamentals.

Here's Mark Perry on speculation.