Climate-addled jet streams boost drought, flood: study

Climate-addled jet streams boost drought, flood: study.
"Our work shows that climate change isn’t just leading to more extreme weather through the usual mechanisms," said lead author Michael Mann, a professor at Penn State University in the United States.
"In addition to these effects, global warming is changing the behaviour of the jet stream in a way that favours more extreme and persistent weather anomalies," Mann told AFP.
Jet streams are ribbon-like currents of air that snake across the northern half of the globe about 8 to 11 kilometres (five-to-seven miles) above Earth’s surface.
Jet streams are the reason it takes an hour less to fly from Los Angeles to New York than the other way around.
Connecting the dots When jet streams slow or stall, these weather systems can become more extreme, leading to extended periods of heat or precipitation.
"Relatively small changes to the jet stream can have a large effect on weather and extreme weather," co-author Dim Coumou, a professor at the Institute for Environment Studies and VU University Amsterdam, told AFP.
And what causes these massive air flows to stall?
It is a smaller temperature difference between the Arctic and tropical air that corrals them on either side.
Earlier research linked jet streams with major drought and floods over the last two decades, but said nothing about whether human activity helped drive the process.

Learn More