Saturday, August 10, 2019

Air turbulence could become three times worse by 2050, thanks to climate change

New Delhi: Airline passengers may face a much bumpier ride in the future, according to a study published in the journal Nature, which found that climate change is having a greater impact on the jet stream than previously thought.

Scientists at the University of Reading, UK, have discovered that the jet stream has become 15 percent more sheared in the upper atmosphere over the North Atlantic since satellites began observing it in 1979.
Vertical wind shear -- the increase in wind speed at higher altitudes -- causes invisible clear-air turbulence, which can be severe enough to throw airplane passengers out of their seats, researchers said.

It terrifies nervous fliers and injures hundreds of passengers and flight attendants every year, they said.

The study shows for the first time that, whilst the temperature difference between Earth's poles and the equator is narrowing at ground level because of climate change, the opposite is happening at around 34,000 feet -- a typical airplane cruising altitude.

The jet stream is driven by these temperature differences, and the strengthening trend at cruising altitudes is causing an increase in turbulence-driving wind shear, which had gone unnoticed until now.
"Over the last four decades, temperatures have risen most rapidly over the Arctic, whilst in the stratosphere -- around 12 kilometres above the surface -- they have cooled," said Simon Lee, PhD student in Meteorology at the University of Reading.
This has created a tug-of-war effect, where surface temperature changes act to slow the jet down, while temperature changes higher up act to speed it up.

"Our study shows these opposing effects currently balance out, meaning the speed of the jet stream has not changed. However, we looked for the first time at the wind shear, where significant change has previously gone unnoticed.
09/08/19 PTI/India Today

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