In the wake of the deadly twister outbreak last week, Sen. Bernard Sanders declared that climate change is making tornadoes worse, to which researchers say: Not so fast.
Purdue University professor Ernest Agee, who has studied tornadoes for 50 years, said his research and that of other scientists shows that the number of violent U.S. tornadoes has in fact tapered off in recent decades.
“My opinion is that strong and violent tornadoes have actually leveled off,” said Mr. Agee. “They’re definitely not increasing with time over the last few decades. In fact, there’s a slight tendency, just a very slight tendency, of the decline in the number of violent and strong tornadoes.”
What’s more, 2018 was the first year since record-keeping began in 1950 without an EF4 or EF5 tornado, the most devastating twisters, as rated on the Enhanced Fujita Scale from EF0 to EF5, according to the NOAA/NWS Storm Prediction Center.
“We’re definitely not seeing a trend of increase. If anything, we’re seeing a decrease in the number of strong and violent tornadoes,” Mr. Agee said, adding “and that’s in papers that I’ve published and my students and other colleagues that are prominent in the field.”
Ten deaths were reported last year from U.S. tornadoes, the fewest since unofficial tabulations started in 1875, breaking the previous low of 12 deaths in 1910. About 70 deaths per year are attributed on average to U.S. tornadoes.
“Last year was, for a lack of a better term, a tornado drought over the United States,” said Victor Gensini, a meteorology professor at Northern Illinois University.
None of that should reassure those living in storm-prone regions, as demonstrated by the destructive March 3 outbreak in Lee County, Alabama, that left 23 dead after a tornado registering winds of up to 170 mph, enough for an EF4 rating, swept through the area.
More tornadoes touched down over the weekend from Texas to Tennessee. The strongest was a twister with EF1 wind speeds in Logan County, Arkansas. The storms produced damage but no reported deaths, according to AccuWeather.
Climate change is inevitably blamed for any natural disaster, and Mr. Sanders led the charge after the deadly tornado, saying in a Facebook post, “The science is clear, climate change is making extreme weather events, including tornadoes, worse. We must prepare for the impacts of climate change that we know are coming.”
The Vermont independent linked to an article in EcoWatch about an October study by Mr. Gensini showing that Tornado Alley is gravitating from the Great Plains to the Midwest and Southeast, but the professor said the shift cannot be attributed conclusively to human-caused climate change.
“[Mr. Sanders] references our study, which says that climate change is shifting eastward. We just don’t know for sure if it’s precisely climate change that’s causing it, and certainly we cannot say at all that climate change caused the Lee County, Alabama, tornado,” Mr. Gensini said. “We’re not there as a science to be able to do that.”
Are tornadoes getting worse because of climate change? “It’s a bit of a premature statement,” said Stephen Strader, Villanova University assistant professor of geography and the environment. “In terms of noticeable trends due to climate change, we don’t see much there yet.”
Tornado damage up, deaths down
According to the Center for Climate and Energy Solutions, the “link between tornadoes and climate change is currently unclear.”
“It is likely that a warmer, moister world would allow for more frequent instability,” the center said on its website. “However, it is also likely that a warmer world would lessen chances for wind shear. Climate change also could shift the timing of tornadoes or the regions that are most likely to be hit, with less of an impact on the total number of tornadoes.”