It’s a flip on a flop. After all the media headlines, a new paper suggests that some climate scientists are not just wrong, they got cause and effect mixed up, and that the wandering “blocking” jet streams are not caused by warmer arctic, but may be causing the temperature changes instead.
“”The well-publicised idea that Arctic warming is leading to a wavier jet stream just does not hold up to scrutiny,” says Screen.
“With the benefit of ten more years of data and model experiments, we find no evidence of long-term changes in waviness despite on-going Arctic warming.”"
The truth is that most big models loosely predicted that global warming would make the jet streams less wiggly, but from the mid 1980s the jet-stream-trend was the other way. As the Arctic warmed the “waviness of jet streams increased”. So in 2012 a few modelers came up with a post hoc rationalization of why, really, truly, actually a warmer Arctic meant that the jets streams would wander more. The media enthusiastically repeated it, though it was contentious and disagreed with most models. But oh dear, by golly, by 2015 the trend started to reverse again. Now in […]
via JoNova
February 21, 2020 at 11:38AM
Iowa Climate Science Education 