Tornado Casualties Could Triple by the End of the Century

A recent study published in the journal Climatic Change found that the amount of death and destruction wrought by tornadoes in the United States could triple by the end of this century—and it’s in large part our own doing. Researchers at Villanova University studying tornado risk and population growth found that human activity will likely contribute to a rise in tornado-related damages and casualties in the coming decades.

The researchers’ findings are almost common sense: As the American population grows and people build homes farther away from urban centers, tornadoes will have more things to run into, putting more people at greater risk for danger during tornado outbreaks.

It’s already possible to see the effects of population growth in the aftermath of recent tornado outbreaks. Most tornadoes tear through open land, primarily damaging farm houses and agricultural equipment. Back when most of the population was either isolated in rural areas or concentrated in city centers, it took the incredible bad luck of a significant tornado directly hitting a city in order to cause a major disaster. But as the suburbs have wildly expanded in recent decades and we've built on more and more land, we’re exposing ourselves to a risk that our parents and grandparents didn’t necessarily have to face. Nowadays, a tornado can tear through a city’s suburbs and claim many lives and thousands of homes—homes that likely didn’t exist 50 years ago.

The researchers also accounted for the fact that the frequency of tornadoes might increase over the next nine decades, but found that this increase alone doesn’t account for additional tornado-related tragedies. Talking about future tornadoes, of course, also inevitably brings up the issue of climate change. While there is significant scientific consensus on many of the effects of climate change, such as rising sea levels and warmer temperatures, scientists still aren’t sure how climate change would affect the frequency or intensity of tornadoes in the future.

Tornadoes require wind shear in order to form. Winds changing speed and direction with height is what causes a thunderstorm’s updraft to begin rotating, which in turn can produce tornadoes. While a warmer atmosphere would foster more intense thunderstorm activity, a uniformly warm atmosphere would probably lessen the amount of wind shear that a thunderstorm could tap into—possibly causing the number of annual tornadoes to hold steady or even drop a bit.

But while climate change’s future effects on tornadoes remain to be seen, researchers have recently noted an uptick in the frequency of tornado outbreaks, or events with many tornadoes on a single day. All of which is to say: An increase in tornado outbreaks combined with an increase in population will likely make tornado tragedies more common in the future.