- Scientist explains how global warming makes turbulence worse for planes
- READ MORE: What is turbulence? The science behind the horrific phenomenon
Air passengers are usually told that turbulence is nothing to be worried about – but as Singapore Flight SQ321 showed on Tuesday, it can prove fatal.
A 73-year-old British man, Geoff Kitchen, died of a suspected heart attack while several others suffered serious injuries aboard the plane, which encountered severe turbulence at around 37,000 feet.
Passengers did somersaults, blacked out and left the cabin in ‘pools of blood’ as it suddenly plunged by around 6,000 feet within minutes.
Now, scientists say climate change is making turbulence worse for planes – resulting in more sudden and violent movement, and increasing the risk of fatalities.
Speaking to MailOnline, Isabel Smith, a turbulence researcher at the University of Reading’s meteorology department, warned that global warming makes jet streams – the narrow currents of fast-moving air that planes fly along to get a speed boost – more ‘chaotic’.
Airport officials stand near the Singapore Airlines aircraft for flight SQ321 parked on the tarmac after an emergency landing at Suvarnabhumi International Airport, in Bangkok, Thailand, May 22, 2024
‘The amount of turbulence is closely linked with the speed and velocity of the jet streams, the fast flowing bands of wind that propagate around the world,’ she told MailOnline.
‘As the jet speed increases, the instability of the jet increases, and air flow becomes more chaotic, leading to more turbulence.’
It’s thought a particular type of turbulence called clear-air turbulence (CAT) impacted SQ321.
CAT is difficult to observe in advance of an aircraft’s track using remote sensing methods and challenging for aviation meteorologists to forecast before it occurs.
‘Clear air turbulence (CAT) is generated due to shearing of winds and so has a strong link to jet streams,’ Dr Smith told MailOnline.
‘Global warming refers to the rapid warming of the lowest layer of the atmosphere, which we live in, called the troposphere.
‘There are several layers within the atmosphere and the layer above the troposphere is the stratosphere.
‘The increase in greenhouse gases traps heat within the troposphere, which would usually be emitted into the stratosphere.
The troposphere is where humans live and weather exists, the lowest layer stretching up to about six miles
‘This creates a strong temperature difference vertically across the atmosphere.
‘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.’
CAT is often described as ‘invisible’ because there’s an absence of any visual clues, such as clouds, that can help experts predict dangerous areas.
‘The main problem [with CAT] is that you can’t see it,’ said Ramalingam Saravanan, a professor at Texas A&M University’s Department of Atmospheric Science who was not involved with the study.
‘The best way I think pilots know about it is when some other pilot has flown through it and radios back, letting them know its location.
‘You can try to predict it statistically, but you can’t predict it by individual case because it is a random process, and the air looks clear and harmless – hence the name.’
University of Reading researchers published a paper last year revealing that severe turbulence has increased 55 per cent over four decades.
By analysing CAT trends globally between 1979 and 2020, the experts found ‘clear evidence’ of large increases of CAT affecting planes at cruising altitudes.
In particular, they found largest increases in CAT have been over the US and North Atlantic – both busy flight regions.
University of Reading researchers found severe turbulence has increased per cent over four decades. Pictured, annual-mean probabilities of encountering moderate-or-greater clear-air turbulence (CAT) in (a) the year 1979 and (b) the year 2020 (darker areas of red indicate greater probability)
Passengers did somersaults, blacked out and left the cabin in ‘pools of blood’ as they were thrown around by turbulence. Pictured, bloodied staff aboard SQ321
A 73-year-old British man, Geoff Kitchen, died of a suspected heart attack and several others suffered serious injuries aboard the plane, which encountered severe turbulence at around 37,000 feet
At a typical point over the North Atlantic, the total annual duration of severe turbulence increased by 55 per cent from 17.7 hours in 1979 to 27.4 hours in 2020, the research found.
Moderate turbulence increased by 37 per cent from 70.0 to 96.1 hours, and light turbulence increased by 17 per cent from 466.5 to 546.8 hours.
While the US and North Atlantic have experienced the largest increases, the experts found that other busy flight routes over Europe, the Middle East, and the South Atlantic also saw significant increases in turbulence.
Interestingly, there’s been a greater increase in CAT in the northern hemisphere than the southern hemisphere, which ‘warrants further investigation’.
According to the team, their study ‘represents the best evidence yet’ that clear air turbulence has increased in the past few decades, in line with global warming increases.
Meanwhile, a 2017 study calculated that climate change will significantly increase the amount of severe turbulence worldwide at some point between the years 2050 and 2080.