Climate change is making plane turbulence worse, and it could make flights bumpier and more expensive

• You may experience more turbulence on future flights, especially transatlantic routes.
• Climate change has altered the jet stream and led to more unpredictable clear-air turbulence.

A Lufthansa flight that had to land shortly after takeoff is just the latest example of extreme turbulence.

Each year, pilots report an average of 5,500 encounters with severe or greater turbulence. And that number has increased in recent years, thanks to climate change.

Several other events have occurred in 2023 alone. The pilot had to abort landing due to severe turbulence on one Southwest flight, while extreme turbulence injured 25 people on a Hawaiian Airlines flight. On the Lufthansa flight, several people on board were injured.

And though death due to turbulence is very rare, a passenger on a business jet died during severe turbulence on March 4.

Experts believe severe turbulence may increase in years to come as patterns of severe weather continue around the globe.

Why is turbulence getting worse?

Turbulence is any irregular and unexpected change in air movement that affects an aircraft's altitude and motion.

It can range from a mild jolt or bump to severe pitching and rolling that causes nausea or injuries, like your head slamming against the seat.

Primary causes of turbulence for commercial jets and airliners include storms, atmospheric pressure, and jet streams.

Generally, pilots use their eyes, radar, and reports from other planes to detect storms and other signs of upcoming turbulence before the plane starts to jolt. This gives them time to turn on the "fasten seatbelts" sign and instruct passengers to take their seats.

But pilots also have to contend with clear-air turbulence, which is turbulence that has no visible cause.

Clear-air turbulence can set the plane shuddering and shaking before the pilot can issue a warning, which makes it especially dangerous — and it's this type of turbulence that's increasing due to climate change.

The link between climate change and clear-air turbulence

A main culprit of clear-air turbulence is wind shear, which is a sudden change in the speed and direction of the wind, particularly within jet streams.

"When the wind is blowing from the west at 100 miles per hour at 30,000 feet and also blowing from the north at only 30 mph at 20,000 ft, or directly underneath, it can be quite turbulent for an airplane moving between those two altitudes," said Stephen Bennett, chairman of the American Meteorological Society's Committee on Financial Weather and Climate Risk, and co-founder and chief climate officer of The Demex Group.

In a nutshell, high wind shear makes for an unstable jet stream and faster wind.

Both of these play a major role in clear-air turbulence, and changing global temperatures have already increased wind shear by 15% since 1979.

Plus, clear-air turbulence tends to develop around upper-level jet streams, where planes typically fly. These fast-flowing bands of wind are strengthening with global warming, said Isabel Smith, meteorologist and PhD student at the University of Reading and lead author of a 2023 article on clear-air turbulence trends over the North Atlantic.

She's currently researching the shifts in clear-air turbulence driven by climate change.

Smith said the increase in greenhouse gasses traps heat in the troposphere, the layer of the atmosphere closest to the surface. But this heat should have been released into the stratosphere, which is the next layer up. As a result, globally the troposphere warms while the stratosphere cools at a rapid rate.

"This increases the temperature gradient between the two layers, which strengthens the jet stream, which in turn creates a more unstable wind flow and increases clear-air turbulence," Smith said.

Weather researchers further predict clear-air turbulence will double by 2050, with severe turbulence increasing the most.

"The highest altitude flights over the North Atlantic will encounter the most significant increase in severe turbulence," Bennett said.

Airlines could take longer, more expensive routes to avoid turbulence

Clear-air turbulence causes a large percentage of weather-related accidents on flights. And turbulence in general is the leading cause of injury among flight attendants.

Even though experts predict the effects of climate change will only worsen, you most likely don't need to worry about increasing turbulence on future flights.

"While it may seem like flying could become more dangerous because of climate change, it's just not that simple," Bennett said — in part because systems for air routing will likely adjust so flights avoid highly-turbulent areas.

"I also expect that newly emerging technology will make it easier to detect clear-air turbulence in the decades ahead," Bennet said. "Even considering the impacts of climate change, it's actually likely that flights will become safer over time as opposed to more dangerous."

Smith added that severe turbulence remains very uncommon.

"If you fly across the Atlantic from, say, New York to London, just 3% of the atmosphere is likely to have light turbulence within it. Only 1% of the atmosphere has moderately severe turbulence, and a few tenths of a percent have severe turbulence," she said.

"This percentage is increasing, so you may encounter more turbulence in the future. But this is much more likely to be light turbulence, which won't cause any serious injuries," Smith said.

She adds, however, that airlines always try to avoid turbulence as much as possible. Thus, increasing turbulence will likely lead to more convoluted flight routes, which could mean longer travel and wait times, along with increased aircraft fuel consumption and CO2 emissions.

In fact, avoiding turbulence may cost airlines an additional $22 million dollars each year, with extra emissions of 70 million kilograms of CO2, Smith said. Planes could also spend about an extra 2,000 hours in the air annually, a research letter found.

As for flying safely, Bennett and Smith offer the same advice: Always keep your seatbelt on when seated, even when the seatbelt sign is off.