Climate Change and the Rising Threat of Clear Air Turbulence (CAT) in Aviation

The recent severe turbulence incident involving a Singapore Airlines flight has brought renewed focus to the phenomenon of Clear Air Turbulence (CAT). Unlike regular turbulence caused by storms or clouds, CAT occurs in cloudless skies, making it invisible to both pilots and conventional onboard weather radar. Research from atmospheric scientists suggests that this hazard is becoming more frequent and intense due to anthropogenic climate change. The primary driver behind this increase is the strengthening of the jet stream. As greenhouse gas emissions trap more heat in the lower atmosphere (troposphere), the upper atmosphere (stratosphere) cools. This widening temperature gap increases the thermal gradient, which in turn intensifies the wind speeds within the jet stream. Consequently, vertical wind shear—the sudden change in wind speed or direction with altitude—becomes more pronounced. When these high-speed air currents interact with slower air, they create unstable, turbulent patches. Studies indicate that severe CAT has increased by approximately 55% in certain regions, such as the North Atlantic, over the last four decades.