Will incidents of extreme turbulence increase in the future during our air travel?

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Last week, the plane operating flight SQ321, which connects London to Singapore, had to make an emergency landing in Bangkok after an episode of extreme turbulence.

The incident is enough to make anyone who is afraid of flying shudder. Struck by violent and sudden disturbances at an altitude of 11,000 meters, the aircraft rose then lowered several meters while staff were serving meals to passengers. Results: one dead, a 73-year-old British man struck down by a heart attack, and 104 injured, including around twenty treated in intensive care.

Turbulence has always been a part of air travel, but its frequency and intensity are expected to increase due to climate change, researchers tell us. Will incidents like that of Singapore Airlines Flight SQ321 increase?

According to the work of Professor Paul D. Williams, of the University of Reading, in Great Britain, the risk of turbulence “in clear air”, that is to say which occurs without warning and in good weather, is called to increase radically if humanity continues to release CO₂ into the atmosphere at the current rate.

The risks of turbulence multiplied

Its computer simulations indicate an increase in the risk of moderate turbulence by 94%, moderate to severe by 127% and severe by 149% over the next 30 years.

Areas at risk of turbulence dangerous for planes could also double in size.

At issue: the impact of climate change on jet streams, these strong high-altitude winds which travel through the atmosphere at full speed, separating air masses, and which are reinforced by global warming.

They are what cause turbulence in clear air, which occurs in the absence of clouds and which is therefore very difficult to detect by radar and to avoid. It is suspected that it was this type of turbulence that struck the Boeing operating Singapore Airlines flight SQ321.

According to studies by Paul D. Williams, their frequency has already increased by 55% since 1979.

Thermal turbulence, for its part, is produced by the convection of hot air in clouds and is detectable by radar. They will also multiply due to the rise in temperatures on the surface of the globe.

“It’s the same principle that we see with the increase in tornadoes, hurricanes or floods. All meteorological phenomena that pass through the sky will necessarily affect planes,” summarizes Mehran Ebrahimi, director of the International Observatory of Aeronautics and Civil Aviation (OIAAC), affiliated with ESG-UQAM.

Despite everything, incidents like the Singapore Airlines flight remain extremely rare. According to the counts made by Professor Williams’ team, the last death attributable to turbulence, regardless of the type, dates back to 2009.

“If the passengers were strapped in…”

In most cases, the injuries are attributable to the fact that the passengers were not wearing their seat belts when the aircraft entered an area of ​​turbulence.

“Regardless of the severity of the turbulence, if the passengers were restrained, the injuries caused by it would be reduced by almost 90%,” estimates Mehran Ebrahimi.

He points out that, regardless of its intensity, turbulence generally presents no danger to the structure of aircraft.

“Airplanes are capable of withstanding pressures 150% higher than what nature can generate,” says Mr. Ebrahimi. The danger of turbulence is when the plane makes sudden movements and people are not restrained. They find themselves thrown to the ceiling, like when you are in a car and driving on a speed bump. »

But if turbulence is harmless to the structure of aircraft, it could well have an impact on travelers’ wallets, since it generates costs for air carriers.

Circumventing a turbulence system involves modifying the flight path and, thereby, increasing its fuel consumption and changing its cruising speed. Airports may also impose fees on carriers whose flights miss the scheduled time slot.

In the United States alone, all of these measures would already cost airlines between $150 and $200 million each year. This may be reflected in the price of tickets.

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