It is really funny how the things work on internet nowadays. You start looking for something and you end reading unexpected things. I was writing and reading about what is turbulence and how to avoid it (last two posts) when I found a recent (2013) interesting paper talking about the possible intensification of turbulence activity due climate change.

The paper is quite interesting. They define turbulence in an elegant way:

…turbulence when they encounter vertical airflow that varies on horizontal length scales greater than, but roughly equal to, the size of the plane.

The Australian Transport Safety Bureau (ATSB), suggested that cases of turbulence had risen and incidents doubled over the three-month period between October and December last year, compared to the previous quarter. Also moderate-or-greater upper-level turbulence has been found to increase over the period 1994–2005 in pilot reports in the United States.

However as I mentioned before there are different types of turbulence as clear air turbulence (CAT), in-cloud turbulence and mountain-wave turbulence. In this particular they studied the CAT possible caused by the jet streams at cruise altitudes. Jet streams are important to aviation because it cuts time off the flight and it also nets fuel savings for the airline industry (this is super important). They studied the period of December, January and February, which are when Northern Hemispheric CAT is thought to be most intense.

They concluded:

…we have found that a basket of clear-air turbulence measures diagnosed from climate simulations is significantly modified if the atmospheric CO2 is doubled. In particular, at typical cruise altitudes in the northern half of the North Atlantic flight corridor in winter, most 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.

Should I be afraid of flying during the winter? Here are the good news. German scientists are working with a new system to detect CAT using lasers (CAT is very difficult to detect with conventional radar) and consequently avoid turbulence. This guy talks really fast, but is a good overview about turbulence and the laser detection:

Here are the bad news. If climate change will lead to bumpier transatlantic flights, even if one can detect accurately CAT, the flight paths should be more convoluted to avoid turbulence that are stronger and more frequent. Thus, journey times will lengthen and fuel consumption will increase. Air companies (as any company in the world) want to make money. Thus, if they have to make profit during the winter it is natural to raise the air fares to compensate these additional costs. Gosh, these are not really good news. If you are in a band and if you want to go on tour you should go during the summer… but wait during the summer is when the air tickets are more expensive….

Remarks: These are results are based on computer simulations. Right now there is not enough data to assign much statistical significance to the trend but we are getting there…

Journal References:

Williams, P., & Joshi, M. (2013). Intensification of winter transatlantic aviation turbulence in response to climate change Nature Climate Change, 3 (7), 644-648 DOI: 10.1038/nclimate1866