Climate change is contributing to a more turbulent plane ride

Invisible turbulence leaves a very visible financial dent

Whether one is an anxious flier or not, turbulence is hard to fly through in an aircraft. Strong turbulence can injure passengers and flight attendants. Turbulence-related damages, delays, and injuries cost airlines around the world up to $500 million per year.

Ph.D. researcher and co-author of the study, Mark Prosser, said, "Turbulence makes flights bumpy and can occasionally be dangerous. Airlines will need to start thinking about how they will manage the increased turbulence, as it costs the industry $150–500m annually in the USA alone.”

One of the most dangerous forms of turbulence is clear-air turbulence (CAT). It gives no visible warning and often occurs when the ‘fasten seatbelt sign’ hasn’t been turned on. The team of researchers analyzed the modern atmospheric data based on four decades (1979 to 2020) of observation. They wanted to know if CAT has already started to increase.

Increase in Europe, Middle East, and South Atlantic

The team used 21 different turbulence calculations to ensure their results were reliable. They found clear evidence of large increases in CAT worldwide at the same altitudes where aircraft cruise.

As an example, the team explained in their study that over a specific point in the North Atlantic, the strongest category of CAT occurred 55% more in 2020 than in 1979. 

The study said that the largest increases were found over the North Atlantic and the continental United States, with increases of 0.3% (26 hr) and 0.22% (19 hr), respectively. Every additional minute spent in turbulence is important as it not only causes fatigue and worry but also increases maintenance costs and the potential for injuries.

Professor Paul Williams, an atmospheric scientist at the University of Reading and a co-author of the study, said, “Following a decade of research showing that climate change will increase clear-air turbulence in the future, we now have evidence suggesting that the increase has already begun. We should be investing in improved turbulence forecasting and detection systems, to prevent the rougher air from translating into bumpier flights in the coming decades.” 

The researchers say that the trends in other forms of turbulence, like convectively induced turbulence (CIT) and mountain wave turbulence (MWT), also need to be studied.

The study was published in the journal Advancing Earth and Space Science.

Study abstract:

Clear-air turbulence (CAT) is hazardous to aircraft and is projected to intensify in response to future climate change. However, our understanding of past CAT trends is currently limited, being derived largely from outdated reanalysis data. Here we analyze CAT trends globally during 1979–2020 in a modern reanalysis data set using 21 diagnostics. We find clear evidence of large increases around the midlatitudes at aircraft cruising altitudes. For example, at an average point over the North Atlantic, the total annual duration of light-or-greater CAT increased by 17% from 466.5 hr in 1979 to 546.8 hr in 2020, with even larger relative changes for moderate-or greater CAT (increasing by 37% from 70.0 to 96.1 hr) and severe-or-greater CAT (increasing by 55% from 17.7 to 27.4 hr). Similar increases are also found over the continental USA. Our study represents the best evidence yet that CAT has increased over the past four decades.