Will Climate Change Increase Transatlantic Aviation Turbulence?

Clear-air turbulence in the upper troposphere and lower stratosphere is a major hazard to aircraft. It also contributes significantly to turbulent mixing across the tropopause. Evidence suggests that clear-air turbulence is caused by the Kelvin–Helmholtz shear instability. Wind shears at typical flight cruising levels in the mid-latitudes are projected to be strengthened by climate change, suggesting that clear-air turbulence statistics may display anthropogenic trends. However, the response of clear-air turbulence to climate change has only recently been recognized and studied.

Here we show using climate model simulations that clear-air turbulence changes significantly within the transatlantic flight corridor when the concentration of carbon dioxide in the atmosphere is doubled. We calculate a basket of 21 different clear-air turbulence diagnostics from the GFDL-CM2.1 climate model. At cruise altitudes within 50–75°N and 10–60°W in winter, we find that most of the diagnostics show a 10–40% increase in the median strength of turbulence and a 40–170% increase in the frequency of occurrence of moderate-or-greater turbulence.

Our results suggest that climate change will lead to bumpier transatlantic flights by the middle of this century. Observational evidence suggests that this increase has already begun. Aviation is partly responsible for changing the climate, but our findings show for the first time how climate change could affect aviation. Any increase in clear-air turbulence could also have implications for the large-scale atmospheric circulation, by modifying the turbulent fluxes across the tropopause.