Extreme weather takes climate change models ‘off the scale’
https://www.ft.com/content/9a647a51-ede8-480e-ba78-cbf14ad878b7Extreme weather takes climate change models ‘off the scale’
Scientists say the shifting pattern of the jet stream is exacerbating the effects of climate change
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Climate scientists say the severity of these events is simply “off scale” compared with what atmospheric models forecast — even when global warming is fully taken into account.
“I think I would be speaking for many climate scientists to say that we are a bit shocked at what we are seeing,” said Chris Rapley, professor of climate science at University College London. “There is a dramatic change in the frequency with which extreme [weather] events occur.”
From the deadly flooding in Germany last week, to scorching heat in Canada, and a deluge in the Black Sea region, the pace and scale of catastrophic damage has been almost unimaginable, even for experts who have spent their lives studying it.
One driver behind many of these events is the shifting pattern of the jet stream, a fast-flowing band of air that governs weather in the Northern hemisphere. It is becoming slower and wavier, particularly in summer months.
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This means heatwaves and drought (linked to high pressure systems) and flooding (linked to low pressure systems) both become more persistent.
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Mann is worried that current models do not reproduce the jet stream behaviour accurately. “This means they are underestimating the magnitude of the impact of climate change on extreme weather events,” he says.
“While the overall warming of the planet is pretty much in line with climate model predictions from decades ago, the rise in extreme weather events is exceeding the predictions,” Mann notes.