Green Scene: A Bumpy Ride Ahead

SmartMeetings.com
By Bill Chapin
Juy 2013

Global warming could create turbulence for airlines - literally

A lot of the climate change debate has focused on how air travel is affecting global warming, but global warming may soon affect air travel. As a result, passengers can expect to see the "please fasten seatbelt" sign illuminated a lot more as they get jostled around by increasing turbulence.

There are several types of turbulence that airplanes can encounter. One of the most common, clear-air turbulence, happens when currents of air at cruising altitudes become unstable. The airflow in this part of the atmosphere is driven by differences in temperature between the earth's polar and tropical regions. Climate change is increasing those differences and, according to a U.K. study released earlier this year, that's going to mean more instability.

Professors Paul Williams from the University of Reading and Manoj Joshi from the University of East Anglia in Norwich, England, published their findings in the scientific journal Nature Climate Change in April. Using a climate model developed for the Intergovernmental Panel on Climate Change, the study looked at supercomputer simulations of the jet stream over the North Atlantic Ocean. "What goes into [these simulations] is our best understanding of the laws of physics and chemistry, plus a projection about how atmospheric carbon dioxide levels will increase in the future," Williams says. The results show an increase in both the frequency and severity of clear-air turbulence in coming decades.

The researchers found that the chances a transatlantic flight will encounter significant turbulence will increase anywhere from 40 to 170 percent by the middle of the century. Most likely, the amount of airspace with significant turbulence at any given time will double. The average strength of the turbulence will increase as well, from 10 to 40 percent. While these findings were limited to the North Atlantic, the researchers believe it will hold true when they make the calculations for other jet streams.

Unlike turbulence associated with clouds and thunderstorms, which pilots can identify and avoid, clear-air turbulence is invisible and undetectable. It's the kind that strikes with no warning while the airplane is flying through clear, blue skies. Because people may be wandering around the cabin when it happens, it is responsible for the majority of turbulence-related injuries. As these shaky situations become more common, pilots may need to adjust their flight paths. That would mean longer flights and more fuel consumption - which, of course, only exacerbates greenhouse gas emissions. "Turbulence is an expensive problem for the airline industry," Williams says, "and we hope [airlines] could join us for calling for further work to understand in more detail what the future holds."