Climate change appears to be exacerbating the frequency of invisible 'clear air' turbulence.

Turbulence poses significant challenges for aviation safety, as evidenced in recent episodes on Singapore Airlines and Air Europa flights that resulted in multiple injuries.

‘Clear air’ turbulence, which cannot be easily detected or predicted, has been increasing, according to a new study.

The research analysed extensive datasets and employed 11 different climate models to investigate the effects of climate change on clear air turbulence. 

The results indicate a 60 per cent to 155 per cent increase in turbulence across regions such as East Asia, North Africa, and the Middle East. 

The study's models consistently show that further increases in global warming will lead to more frequent turbulence in northern mid-latitude regions.

“We know that clear air turbulence is the main cause of aviation turbulence, which causes approximately 70 per cent of all weather-related accidents over the United States,” said Mohamed Foudad, lead author and atmospheric scientist at the University of Reading.

Foudad says future aircraft designs should consider this expected increase in turbulence.

Clear air turbulence typically occurs near jet streams - fast-moving air currents at altitudes where commercial aircraft fly. 

As the climate warms, the energy in the atmosphere increases, which enhances the velocity of jet streams and the occurrence of vertical wind shear, a primary cause of clear air turbulence.

Currently, clear air turbulence is most frequent over East Asia, where planes encounter moderate-to-severe turbulence approximately 7.5 per cent of the time. 

The study's simulations under various warming scenarios from 1°C to 4°C above current levels indicate that turbulence will become more common in the future.

The study found significant increases in moderate-to-severe clear air turbulence over North Africa, East Asia, and the Middle East. However, the results were less conclusive for the North Atlantic and North Pacific regions, where natural climate variability may obscure the signals of climate change.

Still, “we now have high confidence that climate change is increasing clear air turbulence in some regions”, Foudad said. 

Foudad pointed out that while turbulence is expected to increase, modern aircraft are built to withstand severe conditions. 

Even so, the researchers say further research is needed to refine turbulence forecasts and explore whether adjusting flight altitudes could mitigate risks.