Aeroplanes will encounter increased Clear-Air Turbulence (CAT) during flights, in the years to come, according to a recent study published in the journal ‘Nature Climate Change’.
Modelling studies conducted by scientists Paul D Williams and Manoj M Joshi of the UK, predict that the concentration of carbon dioxide will double from that of pre-industrial levels by 2050. The studies also shows that the rise in carbon dioxide will lead to a 10 to 40 per cent increase in the median strength of turbulence and a 40 to 170 per cent increase in the frequency of occurrence of moderate or greater turbulence at cruising altitudes of 12 km or 39,370 ft.
A moderate turbulence can toss items in the aircraft cabin causing injuries to passengers, but these revised levels predicted can be worse. Clear-air and mountain-wave turbulence is the leading cause of injury in non-fatality commercial airplane incidents, says a study on the Boeing website.
S Chakraborty, an aircraft engineer working with an international airline, says, “Till now, we do not have technology in passenger aircraft to detect Clear Air Turbulence created by difference in air composition. We can detect clouds on radar. While regular clouds do not cause turbulence, the moisture-laden one does. The weather radar can make out the difference. However, air pockets cannot be detected in clear skies.
“There is a worldwide concern about detection of CAT. It is also very difficult to come out of Clear Air Turbulence at heights of 28,000-40,000 ft, as the aircraft are at cruising speeds and cannot come out quickly. Other types of turbulence can be avoided at lower altitudes. Even the latest Dreamliner aircraft from Boeing does not have technology to detect Clear Air Turbulence”, he said
An official at the Indian Meteorological Department, says, “Wind, moisture, wind shear and types of clouds play a part in turbulence. Carbon dioxide may not have a large role in turbulence. There may be small air pockets (CAT) because of this.”
However, Padma Bhushan awardee Prof Roddam Narasimha, an aerospace and fluid dynamics scientist, says, “The trouble with modelling studies is that there are uncertainties. Yet, climate change is a certainty. I do not see any cause for alarm, though. Safety levels of aircraft have improved. When we fly through air pockets, ‘Gust Alleviation Technology’ reduces bumpiness automatically and the aircraft is forced down. Today’s technology is better than that of 15 years ago. One can be sure that we will have technology to deal with increasing turbulence in future too.”