Global Response of Clear-Air Turbulence to Climate Change

Clear-air turbulence (CAT) is one of the largest causes of weather-related aviation incidents. Here we use climate model simulations to study the impact that climate change could have on global CAT by the period 2050-2080. We extend previous work by analyzing eight geographic regions, two flight levels, five turbulence strength categories, and four seasons. We find large relative increases in CAT, especially in the midlatitudes in both hemispheres, with some regions experiencing several hundred per cent more turbulence. The busiest international airspace experiences the largest increases, with the volume of severe CAT approximately doubling over North America, the North Pacific, and Europe. Over the North Atlantic, severe CAT in future becomes as common as moderate CAT historically. These results highlight the increasing need to improve operational CAT forecasts and to use them effectively in flight planning, to limit discomfort and injuries among passengers and crew. Plain Language Summary Clear-air turbulence is potentially hospitalizing in-flight bumpiness experienced by aircraft. Often, pilots cannot avoid it, because it is invisible to the naked eye and undetectable by onboard sensors. Previous research suggests that climate change will increase instabilities in the North Atlantic jet stream in winter, generating more clear-air turbulence. This study analyzes changes to clear-air turbulence over the entire globe by the second half of this century. We consider eight geographic regions, two flight levels, five turbulence strength categories, and all four seasons. We find strong increases in clear-air turbulence over the entire globe and in particular the midlatitudes, which is where the busiest flight routes are. We also find that the strongest turbulence will increase the most, highlighting the importance of improving turbulence forecasts and flight planning to limit discomfort and injuries to passengers and crew.