Fasten your seatbelts: Turbulence is on the rise

HALIFAX — Extreme turbulence of the kind that injured seven people on a flight diverted to Newfoundland on Sunday appears on the rise, and airlines need improved technologies to detect it, according to a British researcher.

“We need to take it [air turbulence] seriously,” said Paul Williams, an atmospheric scientist who has published papers arguing climate change is likely to increase the amount of high-altitude turbulence.

“I think there is a compelling case that there’s an increase in turbulence and for investment in improving the detection and prediction of clear air turbulence,” he said in a telephone interview on Tuesday from his office at the University of Reading.

In Sunday’s incident, American Airlines flight 206 was diverted to St. John’s, N.L. Passengers described a lasting bout of turbulence over the Atlantic that suddenly developed into dips so jarring that people were praying for their lives.

The incident came just weeks after air turbulence struck an Air Canada Boeing 777 flying from China to Toronto, resulting in 21 injuries to passengers and the launch of a Transportation Safety Board probe.

Last year, 31 people were injured in air turbulence events, up sharply from the single incident in 2014 and the 15 cases in 2013, according to Transport Canada.

Williams co-published a 2013 paper in Nature Climate Change that used a climate change model to compare a pre-industrial climate with one that contained double the amount of carbon dioxide, and make predictions on longterm increases in air turbulence events over the North Atlantic.

The scientist says carbon dioxide is causing a long-term trend toward temperature changes high in the atmosphere, including at the cruising heights of airliners, and that is changing wind patterns.

“In scientific terms, there is a wind shear. Different layers of the atmosphere are meeting at different speeds and there is a kind of friction and that causes clear air turbulence to break out,” said Williams.

The paper predicts the average strength of trans-Atlantic turbulence at cruising altitudes could increase by between 10 per cent and 40 per cent, and the amount of airspace likely to contain significant turbulence by between 40 per cent and 170 per cent.

“Our results suggest that climate change will lead to bumpier trans-Atlantic flights by the middle of this century,” the paper said.

Williams said many airplanes have technology that can detect turbulence in clouds, but are less capable of detecting turbulence in clear, higher skies.

“We need to come up with better methods for predicting when and where clear air turbulence will strike.”