Impact of Climate Change on Turbulence

One person died and 30 were injured when a Singapore Airlines flight encountered severe turbulence on May 20.[1]Five days later, a Qatar Airways flight also experienced turbulence, resulting in injuries to 12 people.[2]What is causing these high-profile turbulence incidents?

The interior of the Singapore Airlines flight after the turbulence incident (Source: SCMP)

Experts believe that climate change is increasing wind speeds in the upper levels of the atmosphere, leading to more turbulence.[3]While turbulence is often associated with obvious bad weather conditions, clear-air turbulence (CAT) can be particularly challenging for pilots to avoid. CAT is a type of severe turbulence that occurs in cloudless regions and is dangerous because it lacks visual cues, catching pilots off guard.[4]This can be especially hazardous when crew and passengers are moving around or have their seatbelts unfastened.

More specifically, CAT typically occur near jet streams, which are narrow bands of strong winds travelling in the upper levels of the atmosphere.[5]Commercial flights travelling eastward often use these jet streams to shorten flight times and save fuel.[6]In favorable conditions, this speed boost can even shave an hour off flight times.[7]However, as human activity warm the planet, wind shear in the jet stream increases, intensifying clear air turbulence. Over the past 40 years, the total annual duration of severe turbulence has increased by 55%.[8]

Jet stream flowing from the United States to Europe (Source: University of Southampton)

While climate change may lead to faster flights, the increased turbulence can result in injuries and significant costs to airline operators. Singapore Airlines, for example, has offered compensation to passengers injured on the May 20 flight, from US$10,000 for minor injuries to $25,000 for those requiring long-term medical care.[9]The operating cost can also increase for airlines opting to have flights avoid regions of severe turbulence, resulting in longer flight distance and time.

Flying may contribute to just 2.5% of global emissions, but it is also one of the most carbon-intensive activities when you take into the account that not everyone flies and certainly not every day.[10]As such, airlines have a responsibility in tackling greenhouse gas emissions to limit climate change and ensure flights do not become even more turbulent. Cathay Pacific for example has stated it is investing in the use of sustainable aviation fuel.[11]Korean Air has introduced fuel-efficient aircrafts to its fleet, which they claim can cut carbon emissions by 20% to 25% compared to existing models.[12]

What about the immediate term? Airlines should work more closely with weather centres to ensure smoother flights. For instance, the Hong Kong Observatory has recently developed a convection forecast system to provide improved hazardous weather information for airline operators.[13]For passengers like us, it is important to always keep your seatbelts fastened when seated and ensure that carry-on items are securely stowed.[14]