PLEA Network

29 May 2019, Washington Post, Extreme weather has made half of America look like Tornado Alley. Climate change may be confounding the jet stream and making trouble for everyone. Tornadoes have been popping up every day in the U.S. as if coming off an assembly line. They’re part of an explosion of extreme weather events, including record flooding, record cold and record heat. Wednesday brought more of the same, with tornado watches in the Midwest and Atlantic seaboard and 37 million Americans facing an “enhanced” risk of severe weather, according to the National Weather Service. All of which raises the question: Is this climate change, or just an unusually bad year? For years, scientists have warned that climate change caused by human activity — primarily the burning of fossil fuels and the spike in atmospheric greenhouse gases — would make extreme weather events more likely. But tornadoes have never fit neatly into the climate change narrative. They’re eccentric and quirky. Until this year, the U.S. was in something of a tornado drought. Twisters seem to follow a boom-and-bust cycle. There weren’t many tornadoes in 2018. So far this century, two years — 2008 and 2011 — jump off the charts, each with more than 2,000 reported tornadoes. This year, there have been nearly 1,000. The immediate driver of the violent weather is the jet stream, the powerful winds at high altitudes that sweep west to east across North America. The jet stream since May 14 has created conditions ripe for twisters. Seven deaths have been reported so far in the tornado assault of May. That’s a low death toll compared to some tornado seasons, but the steady, percussive nature of the storms — the daily pounding — has been anomalous. Read more here