Slacker Tornadoes?

Certain skeptical readers of Power Line may be surprised to find out that I am actually a dues-paying member of an environmental organization, the Society for Conservation Biology (I’m also a board member of a foundation that does land conservation projects in the Midwest), because the SCB studies ecoystems and biodiversity issues, which are to my mind the most legitimate environmental issues we don’t have a handle on, rather than global warming, toxic chemicals, and the other hoo-hah the political environmental groups dine out on in their direct mail letters and splashy ad campaigns.  If you join SCB, you get a subscription to Conservation magazine, which is nowadays published by the University of Washington in collaboration with several environmental groups including the SCB.

Does it watch football on the weekends?

The latest issue points to a journal article that notes an anomaly: there are fewer tornadoes on weekends.  Slacker tornadoes?  The article, from the Journal of Geophysical Research, thinks that emissions from cars, trucks and factories during the week marginally increase particulates that form the nuclei of water droplets, and this cascades into more water droplets and updrafts that spin into tornadoes.

It sounds plausible, but if so it will be a declining problem as fine particulate levels (PM2.5 in the trade) are falling fast and are going to keep falling.  But it’s interesting because it tracks another anomaly that gets very little attention: in some parts of the country, ground level ozone levels are nowadays higher on weekends than during weekdays, even though there is less driving and industrial activity on weekends.  This counter-intuitive “weekend effect” is driving air quality specialists slightly crazy at the moment, and illustrates how ozone, which is not a directly-emitted air pollutant, is more complex than other forms of air pollution.  And it presents the following problem: as we reduce emissions from all sources further, such that the weekday emissions inventory comes to look like the weekend emissions inventory today, what’s going to happen to ozone levels in those peculiar areas where the “weekend effect” is observed today?  That’s right—ozone may go up (at least temporarily), and you can expect clueless environmental groups to scream about it.

It’s a complicated story, which I wrote about at some length a few years ago along with Joel Schwartz.