No throwing caution to the wind

PETALING JAYA: Aircraft flying over the mid-latitude region have a higher likelihood of facing unexpected and extreme wind conditions that have been exacerbated by the effects of global warming, say climate experts.

Meteorological Department director-general Muhammad Helmi Abdullah said scientific research has shown that global warming can cause air turbulence within convective clouds such as the cumulonimbus and large cumulus.

“Extreme air turbulence can occur with the recent rise in global warming and also from the forming of more convective clouds,” he said, referencing a US study indicating a 50% rise in air turbulence due to jet stream flow, with this trend expected to escalate.

On aircraft safety, Muhammad Helmi affirmed that modern aircraft are engineered to withstand turbulent conditions.

He said air travel will continue becoming safer in the future as advancements in technology develop.

“Based on records and statistics worldwide, air travel remains the safest mode of travel compared to land and sea travel,” Muhammad Helmi said.

Dr Fredolin Tangang, a fellow of the Academy of Sciences Malaysia, said there are two types of air turbulence affected by the changes in climate, namely clear air turbulence (CAT) and non-clear air turbulence (non-CAT).

Not just hot air: (From left) Fredolin, Azizan and Muhammad Helmi.

“CAT and non-CATs are likely to be influenced by global warming and climate change. The likelihood of CAT is higher in mid-latitude regions.

“As for non-CAT, it can occur anywhere, especially in the tropical region where convective systems are common,” said Fredolin, who is also a former vice-chair of the Intergovernmental Panel on Climate Change Working Group 1.

He said moderate turbulence had increased by 37% while light turbulence rose by 17% from 1979 to 2020.

Fredolin said as for non-CAT turbulence, evidence is clear that for every 1°C of global mean temperature increase, the moisture content in the atmosphere will rise by 7%, which can spike threefold in extreme weather conditions.

Sultan Mizan Antarctic Research Foundation climatologist and meteorological expert Prof Datuk Dr Azizan Abu Samah said CAT is generated by wind shear in the jet stream.

He said this can generate atmospheric waves and when it intensifies and breaks, it causes CAT, similar to waves of the ocean slamming into the shore.

“There are two pathways that strengthen the jet stream. One is due to temperature differences, known as baroclinic.

“For example, the bigger the temperature difference is between the polar region and the tropics, the stronger the jet stream. This is why the jet stream is stronger in winter.

“The other depends on the Hadley cell circulation in the tropics, which is associated with thunderstorms.

“With global warming, I believe thunderstorms in the tropics are stronger. This in turn strengthens the jet stream,” said Azizan.