Expert comment: Turbulence is rare, but getting worse

Following a number of recent reports of severe turbulence on flights in the US, Isabel Smith, a turbulence researcher at the University of Reading’s Department of Meteorology, said:

“While there have been some high-profile and concerning recent stories about aircraft encountering turbulence incidents, people should remember that encountering severe turbulence is still very rare.

“Several scientific studies, including by myself and colleagues at the University of Reading, have projected that clear-air turbulence will increase over time as a result of climate change. This is because the upper atmosphere is warming faster in the tropics, as a result of greenhouse emissions, than in the polar regions. This greater difference in temperature between low and high latitudes increases wind shear in the jet streams, the high-level wind currents that blow 10 km above our heads where planes fly, which in turn enhances the formation of turbulent patches of air.

“Even so, airliners are much more likely to encounter light turbulence than severe turbulence. Most of the time, it will be turbulent enough to knock your drink over and make the journey feel a bit bumpy, but not enough to cause any serious injuries.

“The main problem with clear air turbulence for pilots is that it develops where there are no clouds, so is hard to see or detect with on-board radar equipment. As a result, turbulence can hit an aircraft suddenly and without warning. This is almost always fine for the plane, but can be uncomfortable for passengers. This is why airlines recommend when travelling to wear your seat belt as much as possible, even when the seatbelt signs are switched off.

“When clear air turbulence is reported by pilots, airlines will try to avoid turbulence as much as possible for later flights in the area. As a result, as turbulence increases in the future, flight routes may become longer and more convoluted in order to avoid them. These longer travel and waiting times would also increase fuel consumption and emit more CO2.”

Isabel Smith is a PhD student based at the Department of Meteorology at the University of Reading. Earlier this month, Isabel published a paper in Climate Dynamics, titled Clear-air turbulence trends over the North Atlantic in high-resolution climate models.

Smith, I.H., Williams, P.D. & Schiemann, R. Clear-air turbulence trends over the North Atlantic in high-resolution climate models. Clim Dyn (2023). https://doi.org/10.1007/s00382-023-06694-x