Climate Change Making Flights Bumpier With Increase In Severe Air Turbulence: Researchers

Air travel is considered one of the safest means of travel, and turbulence is something air passengers routinely experience. But a string of recent incidents has served to drive home the fact that turbulence can be dangerous, even fatal. And now experts are warning that air passengers can expect to experience more air turbulence as the planet warms.

Dana Hyde, 55, died from blunt-force injuries she sustained while traveling on a business jet that was struck with severe turbulence on March 3. In another incident, a Lufthansa flight from Texas to Germany was forced to land in Virginia on March 1, leading to seven passengers being taken to the hospital.

Around 20 other passengers and crew members were injured during a flight from Germany to Mauritius on March 2 due to air turbulence.

According to figures available on Federal Aviation Administration (FAA)'s website, a total of 146 serious turbulence injuries were reported between 2009 and 2021. These numbers could increase over the next decades due to climate change, according to some experts.

There are different types of air turbulence, but the one that pilots are most weary of is Clean-Air Turbulence (CAT).

CAT "is one of the largest causes of weather-related aviation incidents," as per a study led by Paul Williams, Professor of Atmospheric Science, at Reading. The 2017 study found that occurrences of CAT would increase up to three times in future decades. The rate of injuries would also nearly triple by 2050, the researchers estimated, according to MetMatters.

Isabel H. Smith, who published a scientific study on turbulence and climate change this week under the guidance of Williams, explained that CAT occurrences are not only increasing but also cannot be detected by onboard flight radar equipment. Hence, pilots can encounter them "without warning," she said.

"CAT is a type of upper-level atmospheric turbulence that develops due to the shearing of winds around fast-flowing bands of air (jet streams)," Smith told International Business Times. "CAT develops in cloud-free environments and is therefore undetectable to on-board flight radar equipment. Aircraft flying at their cruising heights (30-40 thousand feet from the surface) can be struck suddenly from CAT without warning, resulting in damages and injuries."

It is possible for pilots to detect some types of air turbulences and deviate around them, but the same cannot be done for CAT.

"As pilots, we can typically see weather buildups with associated turbulence out our windows or on the aircraft radar, and therefore we can deviate around them, depending upon the distance. More challenging than turbulence associated with thunderstorm buildup is Clear Air Turbulence (CAT)...," Karlene Petitt, a retired Delta Captain and author with a Ph.D. in Aviation Safety, told IBT.

Turbulence is "a natural part of aviation" and pilots "are very much aware of that during our daily operations," said The Third Culture Pilot, an airline pilot with 111k followers on Instagram. The pilot explained that there are measures to prepare for air turbulence, but it is not always possible to predict exactly when or where they may encounter CAT.

"Typically we prepare all our flights each day with the use of comprehensive weather charts and other meteorological data, in order to ensure the safest flight possible," he told IBT. "These charts usually give us a good overview of the present weather systems at the departure airport, the en-route areas, as well as our destination and possible alternate airports."

"Unfortunately, even the most advanced weather radars in our aircraft are not able to detect areas of clear air turbulence ahead of us," he added. "Instead, they are very good at locating thunderstorms and areas of weather build-up."

Researchers are warning the aviation sector and air travelers to prepare for a more turbulent future. All severities of CAT, from light to severe, are projected to increase in time due to global warming, Smith said, adding, "This has been proven through a large number of studies. This increase has been found globally."

In the 2017 study by Williams and two others, eight geographic regions were analyzed. And the findings suggested that air turbulence would increase in all the regions.

"Annual mean percentage change of severe turbulence could increase by 181.4 %, 112.7 %, 91.6 %,160.7%, 62.0%, 51.1%, 64.1% and 52.5% over the North Atlantic, North Pacific, Europe, South America, Africa, Asia, and Australia from pre-industrial times," Smith said about the findings.

To explain the science behind why flights get bumpier when the earth gets warmer, it is important to remember a common phrase in science: "Hot air rises, cold air sinks."

"There are several layers within the atmosphere, the bottom layer closer to the surface is the troposphere. The layer above this is the stratosphere. The increase in greenhouse gases traps heat within the troposphere, which would usually be emitted into the stratosphere. Therefore, the stratosphere is cooling at a rate similar to tropospheric warming," Smith explained.

"The colder denser air sinks and pushes the lighter hotter air up. This can happen in any direction (not just up and down)," Jesse Capecelatro, an Associate Professor at the University of Michigan, told IBT.

The process leads to a strong temperature difference vertically across the atmosphere, hence, triggering more occurrences of CAT.

"A stronger vertical temperature gradient will lead to a stronger and more chaotic jet stream. As jet streams get stronger, it gets more chaotic and unstable, and the number of CAT encounters increases," Smith said.

To tackle the rise in severe air turbulence incidents, the long-term solution would be to research the best way to reduce greenhouse gas emissions, whereas the initial fix would include making changes to flight routes, she said, adding, "In-terms of what the aviation industry could do to avoid CAT is use these optimal flight routes and CAT forecasting tools to avoid it as much as possible."

Capecelatro, who believes previously-used methods of predicting severe weather may be unreliable in the future, said experts may have to develop and rely on other models of prediction.

"It is likely that historical data that has previously been relied on for predicting weather, coastal flood events, etc. will become less reliable as the climate continues to change," he said. "Physics-based numerical models that combine observations with governing equations will become more and more important for obtaining accurate predictions."