How the climate crisis is affecting tornadoes – KION546

By Rachel Ramirez, CNN

the series of tornadoes that ravaged the Midwest and Southeastern United States this weekend adds to another spate of deadly and potentially unprecedented weather disasters this year, exacerbating the already growing economic toll of climate disasters across the country.

And in the aftermath of that deadly night of extreme weather conditions, which meteorologists and climatologists consider historic, questions about intensifying climate change, tornadoes are starting to emerge.

In Kentucky, the series of tornadoes uprooted trees, destroyed homes and infrastructure, and killed at least 70 people. Governor Andy Beshear told a press conference that the tornado event reached a “level of devastation like I have never seen before,” he said.

But unlike other extreme weather events such as droughts, floods and hurricanes, scientific research on the link between the climate crisis and tornadoes has not been so strong, making the link particularly difficult.

Scientists say the short-lived scale of tornadoes, coupled with an extremely inconsistent and unreliable historical record, make it extremely difficult to link epidemics and long-term human-made climate change.

Victor Gensini, a professor at Northern Illinois University and one of the top tornado experts, said last night’s outbreak was one of the most notable tornado events in US history – and although climate change may have played a role in his violent behavior, this is not yet the case. clearly what that role was.

“When you start pulling together a lot of these events and start looking at them in the aggregate sense, the statistics are pretty clear: not only has there been some sort of change – a change, if you will – of where the most frequency of tornadoes occurs, ”Gensini told CNN. “But these events are perhaps becoming stronger, more frequent and also more variable.”

Gensini’s research found that over the past four decades, the frequency of tornadoes has increased increased in large areas the Midwest and Southeast, while diminishing in parts of the Great Central and Southern Plains, an area traditionally known as “tornado alley.” Some studies also indicate that climate change could be contributing to an eastward shift of the tornado alley, for example, leading to more tornadoes in more populous states east of the Mississippi River, like this tornado outbreak. .

“It’s also very common when you have La Niña in place to see this eastward shift of the highest tornado frequency,” Gensini said. “But if you look at the last 40 years, the research that I’ve done… has shown that places like Nashville, Tennessee, for example – or Mayfield, Kentucky, which we saw were affected last night – their frequency of tornadoes, their risk of having a tornado has increased over the past 40 years.

Tornadoes take shape under particularly specific atmospheric conditions, but are primarily fueled by warm, humid air from strong winds that change direction with altitude. Scientists have warned that increased greenhouse gas emissions into the atmosphere are drastically changing the climate system, even causing the jet stream – rapid air currents in the upper atmosphere that influence daily weather conditions that could start a tornado – behave strangely.

Jennifer Marlon, a climatologist at the Yale School of Environment, told CNN it was too early to say what sparked last night’s outbreak, but there are “some really important signatures that suggest it could very well being linked to climate change “, and that scientists” are observing changes in epidemics, not only the severity of individual epidemics and tornadoes, but also quiet periods “.

For example, if one of last night’s tornadoes is rated EF-5 (estimated winds of 260 mph or more), that would end a streak of 3,126 days since the last EF-5, which is the longest. period without the record breaking start in 1950. The last EF-5 tornado was the Moore, Oklahoma, May 20, 2013 tornado.

And as climate disasters worsen and spread, Marlon also highlights important factors that increase disaster risk in society during these times, including worsening weather disasters, increasing exposure to due to population growth and more vulnerable infrastructure.

This is already taking shape in Mayfield, Ky., Where officials say the city’s main fire station and some of its police assets have become inoperative due to last night’s devastating tornado system. Now authorities are looking for other ways to respond to emergency calls.

“All of these things are fueling an increased risk of disaster, with many more consequences, including deaths, of course, but also enormous economic damage,” she said.

As the climate crisis accelerates, more and more people will be vulnerable to the most serious consequences of extreme weather events. Experts say cities should no longer postpone adaptation plans and instead treat them as a larger emergency response system.

But Gensini said one thing is for sure: Regardless of climate change, these types of tornado disasters will continue to worsen as humans change the landscape and build bigger, more sprawling cities.

“We have more assets and more targets for severe storms to hit,” he said. “So even if you take climate change out of the equation, which is very likely to make the problem worse, we still have this problem of human and societal vulnerability.”

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CNN meteorologist Brandon Miller contributed to this report.

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