The latest IPCC science report affirmed an increase in U.S. tornado clusters.

By Bob Berwyn, Inside Climate News

Adding a grim exclamation point to a year of deadly climate extremes, the early December tornadoes that killed at least 90 people in the Southeast were some of the most intense storms on record so late in the year.

The storms fired up in Arkansas the night of Dec. 10, during weather far too hot and humid for the season, and raced across MissouriIllinoisTennessee and Kentucky on Dec. 11. It will take weeks of analyzing data to make final classifications of the tornado outbreak’s intensity. But some of the mega-twisters that destroyed lives, livelihoods and communities may have raked the ground for 250 miles and thrown debris 30,000 feet high into the atmosphere.

exhaust from a smoke stack on the left and a tornado on the right

So far in 2021, nine severe storm episodes (not just tornadoes) have caused $15 billion in damage and accounted for half of the climate-related events on the federal billion-dollar disaster list. The increasing trend of damages from severe storms has also been tracked by the insurance industry, which shows losses steadily increasing for 40 years.

 In 2017, a research meteorologist with Munich Re, a global reinsurance company, wrote in a newsletter that “an increase of atmospheric heat and moisture due to our warming climate will likely increase the number of days per year that are favorable for thunderstorms and their associated hazards, including tornadoes.”

It’s not yet clear if and how global warming fuels individual tornadoes, because they are so small they can’t be reproduced by climate models. But after a Northern Hemisphere summer of floodsdroughtssmoky wildfires and heat waves, climate scientists and meteorologists on social media and in broadcast interviews placed the December tornadoes squarely in the context of global warming.

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