In recent months, incidents of extreme turbulence have been making headlines. There was the Hawaiian Airlines flight from Phoenix to Honolulu this past December on which 36 people were injured and received medical treatment. In March this year, a Lufthansa flight from Austin to Frankfurt was diverted to Washington Dulles after experiencing severe turbulence—seven passengers were taken to the hospital for minor injuries.
Recent stories of turbulent flights have been amplified by video footage (and celebrity reports) that often make the rounds on social media and further fuel questions and concerns travelers might have about these latest in-flight incidents—and whether they indicate an uptick in potentially dangerous turbulence on commercial flights.
Passengers are right to be worried. Studies show that turbulence is feeling the effects of climate change—and not in a good way. But whether that means we should expect a greater frequency—or severity—of turbulence on passenger flights is another story. Here’s what to know about the changes in turbulence in a climate changed world and how it could affect your future flights.
Is turbulence getting worse?
As long as there has been air travel, there has been turbulence. It’s the movement of air that is created by changes in atmospheric pressure, jet streams, mountain air environments, weather fronts, or thunderstorms, as defined by the Federal Aviation Administration (FAA).
“Turbulence can give an airplane a sudden jolt,” the FAA notes.
A growing body of research has found that climate change is having a direct effect on the atmospheric conditions that contribute to turbulence, resulting in a higher frequency and severity of turbulence—specifically a category of turbulence called clear-air turbulence.
Clear-air turbulence is “quite a dangerous type of turbulence to encounter because . . . you can’t actually see it through onboard radar equipment,” says Isabel Smith, a meteorologist currently completing a PhD at the University of Reading, whose research focuses on clear-air turbulence over the North Atlantic region. She notes that “the main problem with it is it comes out of the blue, it can be quite sudden, and passengers, pilots, and crew don’t have enough time to prepare.”
Smith says that the reason instances of clear-air turbulence are increasing is because of the impact that changing temperatures are having on the jet streams, which are narrow bands of strong wind that typically flow from west to east across the globe. (Earth has four main jet streams: two polar jet streams near the north and south poles and two subtropical jet streams closer to the equator.)
While the tropospheric layer of the atmosphere (the layer that we live in) is warming at a rapid rate, the layer above it, known as the stratosphere (the lower layer of which commercial aircraft typically fly in), is actually cooling at a similar rate. That’s because the increase in greenhouse gases is trapping heat in the troposphere (hence, the global warming we’re experiencing) that would have otherwise been emitted into the stratosphere. Consequently, the difference in temperatures, or the temperature gradient, between the troposphere and stratosphere is becoming more exaggerated.
“Jet streams are becoming more intense because of this temperature gradient leading to more turbulence. At the outer edges of these jet streams, you have chaotic air spiraling out and that’s basically the clear-air turbulence that you encounter,” says Smith.
Smith, along with Dr. Paul Williams, a professor of atmospheric science at the University of Reading, published a report in March 2023 that found that while historically winter has been the most turbulent season, climate change models indicate that the summer and fall seasons are projected to experience the largest increase in clear-air turbulence frequency. “By 2050, summers are projected to become as turbulent as 1950 winters and autumns,” their research concluded.
That followed a 2017 report from Williams that found that every type of clear-air turbulence, from light to severe, is likely to experience an increase, but that severe clear-air turbulence would increase the most—by 149 percent—if atmospheric carbon dioxide concentrations were to double.
Dr. Robert Sharman, a project scientist at the National Center for Atmospheric Research (NCAR) says that his research has found that there is likely to be an upward trend in other types of turbulence due to climate change as well, “including turbulence related to air flow over mountains, known as mountain-wave turbulence, and turbulence above clouds forced by convection below.”
He says, “Much of the interest in climate change and turbulence seems to have come from several encounters that have occurred lately,” referring to widely reported episodes such as the Hawaiian and Lufthansa flights cited above. But, he adds, “These have been related to in-cloud turbulence, so they were not in clear air. There is, however, some evidence that the incidents of [turbulence caused by] convective clouds is increasing as well. In the end though, it’s impossible to say if these particular incidents are related to global warming or were just due to bad luck.”
Are flights becoming more turbulent?
While research has found that climate change is having an effect on the intensity and amount of turbulence occurring in the atmosphere, it’s less clear whether turbulence is being experienced on a greater number of flights. That’s because there’s no clear year-over-year data to indicate a succinct trajectory.
The National Center for Atmospheric Research reports that above the United States, an average of 65,000 pilot-reported encounters with turbulence that is moderate or greater occurs each year, plus an average of 5,500 severe-or-greater pilot-reported encounters with turbulence annually. But NCAR doesn’t provide year-over-year comparison data.
The only year-over-year data currently available concerns serious in-flight injuries caused by turbulence, and those numbers have gone up and down in recent years in a way that makes it hard to come to any sort of concise conclusion. For instance, the number of serious turbulence injuries in the United States between 2009 and 2022 ranges from as few as 5 or 6 (as was the case in 2013, 2014, 2020, and 2021) to at most 17 or 18 (numbers recorded for 2009, 2011, and 2022), according to a Federal Aviation Administration report released in March 2023 and based on data compiled by the National Transportation Safety Board (NTSB). The NTSB requires airlines to report “serious injuries and fatalities,” with a serious injury defined as requiring hospitalization for more than 48 hours, or one resulting in a bone fracture or severe damage to internal organs or body parts.
While the 17 serious turbulence injuries reported in 2022 were the highest number of serious injuries due to turbulence since 2011, when 18 were reported, U.S. airlines carried 853 million total passengers in 2022 (they carried 804 million passengers in 2011), according to the Bureau of Transportation Statistics. So, those 17 serious injuries represent a small fraction of the total number of passengers. And while 2020 and 2021 saw just 5 and 6 serious turbulence injuries, respectively, those were also pandemic years that saw far fewer passengers flying.
“Turbulent-related injuries don’t show a clear trend recently,” says Kristy Kiernan, associate director for the Boeing Center for Aviation and Aerospace Safety.
Will there be more in-flight turbulence in the future?
Whether more turbulence in the air will result in passengers experiencing more turbulence in-flight in the near to midterm future is also a bit of an unknown. And that’s due to a variety of flight planning and safety protocols that happen both before and during the flight to curb turbulence encounters.
“In aviation it’s all about risk mitigation,” says Kiernan.
Much of the risk mitigation regarding turbulence occurs before the flight even takes off, as air traffic controllers and airlines analyze weather systems and use radar and LIDAR technology (the latter uses lasers in lieu of radio waves) to detect changes in the environment that aircraft can adapt to in order to avoid bumpy air.
“In terms of [flight] route planning to avoid turbulence, that’s where we have the best tools right now,” says Kiernan. “We have climate models that can help us predict where areas of rapid change in speed and direction of wind are expected to occur. That information given to dispatchers can be helpful in planning routes at different altitudes or at different horizontal or vertical navigation to avoid those areas.”
There is one interesting hiccup when it comes to route planning to avoid clear-air turbulence, however. The airline industry is currently investing heavily in reducing emissions—the very emissions that contribute to climate change and thus to the increase in turbulence—and one way to reduce emissions is to fly shorter, more efficient routes.
“It’s a very tricky situation,” says Smith of the University of Reading. “But the problem is you probably will hit turbulence on the most efficient flight routes.” In a true climate change Catch-22, in order to avoid turbulence as much as possible, airlines would ostensibly need to fly longer, less-efficient routes to get around those bumpy patches.
In the meantime, the air travel industry is working overtime to create and improve systems that would enhance turbulence detection and mitigation in-flight—perhaps helping to avoid the need for those longer, less-turbulent flight routes.
While clear-air turbulence is not detectable with current onboard radar systems, Smith notes that some studies have found that LIDAR technology can detect clear-air turbulence. It remains to be seen whether the industry will invest in implementing LIDAR equipment on commercial aircraft to help pilots better navigate around it. But it can also be used by ground teams to help navigate around certain clear-air turbulence patches prior to takeoff.
There are other tools that pilots can and do use as well, including real-time turbulence sharing data systems.
“Many commercial aircraft are equipped with systems that will automatically record any exceedance of a certain amount of vertical acceleration that would indicate turbulence and then that information automatically goes to a third-party provider. That will then alert subscribing airlines and send that information to the cockpit [about] what areas are experiencing turbulence at that time,” says Kiernan.
The International Air Transport Association (IATA) has one such data sharing system called Turbulence Aware. Others include SkyPath and NASA’s Turbulence Auto-PIREP System, or TAPS.
She adds, “The other thing, too, and this is very analog and very old school, are pilot reports. Pilots will provide to air traffic control [with] ride reports.” She explains that other pilots flying through the same region can then “request ride reports from air traffic control to try and avoid areas of turbulence.”
Kiernan notes that when pilots do encounter a stretch of unavoidable severe turbulence, they will typically slow down to avoid overstressing the airplane. Pilots will also often opt for a different flying altitude to avoid turbulence.
Given the influx in turbulence, is flying still safe?
Despite the mitigation efforts currently in place to avoid rocky patches of air, turbulence remains the leading cause of injuries to cabin crew and passengers in nonfatal flight accidents, IATA reports.
But Kiernan notes that turbulence alone is “not going to bring down an airplane.” The chances are slim to none that turbulence in and of itself would cause a commercial plane to crash, she says.
So, when is turbulence unsafe? “Turbulence is serious if you are not tethered down in the airplane. It’s serious from an internal perspective but it’s not harmful to the airplane. So, when people get frightened in turbulence, as long as they’re buckled, and there’s nothing around them that’s going to fly around,” they are safe, explains Kiernan.
When moderate to severe turbulence strikes, three categories of people on the aircraft are at greater risk:
Flight attendants’ job entails being up and about the cabin much of the time, which means they are less likely to be buckled in than passengers and are at greater risk of being injured if the plane gets jostled around. This is why pilots will request that flight attendants do take their seat when the aircraft encounters moderate to severe turbulence so that they can buckle up and remain safe.
While U.S. airlines allow babies and small children under two to travel as a “lap baby” or “lap child,” the FAA advises that the safest place for a child under the age of two on a U.S. airplane is in car seat that has been approved for use on an aircraft, “not in your lap”: “Your arms aren’t capable of holding your in-lap child securely, especially during unexpected turbulence, which is the number one cause of pediatric injuries on an airplane.” The issue, of course, is that a lap child flies for free, and in order to fly with a car seat, the family must pay for the seat that holds said car seat. The Association of Flight Attendants recently called for a ban on lap babies due to an increase in extreme turbulence and the risks it poses to small children who are not properly secured in a car seat.
People who don’t fasten their seat belt
For passengers who choose not to buckle up for much of the flight, “it’s their own choice,” says Kiernan. “But they can become a projectile, too. Personally, I don’t understand why anybody isn’t buckled up unless they’re actively going to the bathroom or getting something out [of the overhead bin]. Just buckle up. It’s not that big a deal to keep you safe.”
Echoing Kiernan’s sentiment, Dr. Sharman of the National Center for Atmospheric Research concluded: “In the end, [turbulence] forecasts are not perfect, and it is always a good idea to keep buckled up.”