A Singapore Airlines flight from London to Singapore experienced severe turbulence last month, resulting in the death of British passenger Geoff Kitchen.
While turbulence of such intensity is rare, recent studies suggest that climate change could be increasing the risk.
To determine if climate change played a role in this incident, it’s important to understand the nature of the turbulence involved.
Turbulence refers to the irregular movement of air creating currents that can cause an aircraft to roll, pitch, or drop suddenly in altitude.
There are various causes of turbulence, including air flowing over mountains, clouds, and bad weather. The specific cause of turbulence on flight SQ321 is still unknown, but it likely involved either “clear air” turbulence (CAT) or thunderstorms based on weather forecasts.
“Clear air” turbulence occurs when there’s a change in wind direction around the jet stream, a fast-flowing air current found at 30,000-60,000 feet.
A 2020 study by scientists from Reading University revealed a 55% increase in severe CAT in the North Atlantic between 1979 and 2020. This increase is attributed to warmer air from rising greenhouse gas emissions, which alters wind speeds in the jet stream.
CAT is particularly challenging for pilots because, despite meteorological warnings, it cannot be detected by radar during flight.
Prof Paul Williams, an atmospheric scientist at the University of Reading, who co-authored the study said last year: “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.”
Thunderstorms also cause significant turbulence. These storms are produced by cumulonimbus clouds, which can tower high into the atmosphere, often beyond the altitude where planes fly. These clouds form when warm air rapidly rises and cools, condensing in the atmosphere.
Inside cumulonimbus clouds, strong updrafts and downdrafts create severe turbulence. Thunderstorms are powerful, with energy levels comparable to 10 Hiroshima-sized atomic bombs.
Weather forecasts indicated thunderstorms near Myanmar at the time the Singapore Airlines plane was flying.
The UN’s climate science body, the IPCC, reports strong evidence that climate change is intensifying such tropical storms. This is due to warming oceans, which increase water evaporation and add heat and moisture to the air.
Additionally, warmer air holds more moisture, leading to stronger winds and more intense rainfall, which exacerbate turbulence.
However, there is no clear evidence yet that these tropical storms are becoming more frequent.
Over the coming months, investigators will analyse data from the plane’s systems to determine the exact cause of the turbulence experienced on flight SQ321.
Prof Williams said this data can “be used in scientific research, to help understand the causes of turbulence and improve our turbulence prediction systems.”
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