Are aircraft flying into higher energy storm systems because of the effects of climate change? If so, what can we expect in the future? Most likely, an increase in the number of damaged and perhaps crashed aircraft, although no one can say for certain. It is still not clear what happened to the Air France Flight 447 Airbus A330-200 that disappeared over the Atlantic en route to Paris, though its electronic systems indicated serious malfunctions but the root cause is not yet known.
However, what is known is that there were severe storms in the area in which the aircraft was flying, with vertical wind speeds of up to 100mph (160kph). These winds had the potential to cause large vertical shear loads on an aircraft, sufficient perhaps to cause either structural damage, or to exceed the pre-programmed flight limits of the aircraft, causing software glitches and systems to fail. Once these systems fail, human intervention is required but modern aircraft fly at the extreme limits of velocity, thrust and stability in order to maximize efficiency. It seems, according to some industry comments, that it is difficult to fly an Airbus A330 manually in this part of the flight envelope – high speed, high altitude cruise.
Adding in the fact that severe thunderstorms, and likely freezing conditions at high altitudes, with moisture driven there by the storm updrafts, one can easily imagine that any system failure requiring pilot interaction would be a hundred times more difficult to deal with, along with extreme buffeting from vertical wind shears.
So why should these storm systems be any different now due to global climate change effects? Why would increased storm severity be affecting aircraft more than usual?
The second question is actually easier to answer than the first, and is due to two effects. Firstly, as the aircraft population ages, and older planes are passed along to airlines that may skimp a little on maintenance or pilot training, it is easier to understand why storm effects on aircraft might turn out to be more damaging than previously. In addition, since there is an incessant drive to minimize travel costs and maximize profit, aircraft design is getting pushed to the limit, not only in terms of aerodynamics and engine technology, but also in terms of software control of systems and constant aircraft flying, with barely enough time between stop-overs for a refuel, a check-over and a quick clean.
The flight engineer – the original aircraft systems expert has long been deleted from the flight cockpit crew to save a salary and a seat, to be replaced by even more automatic systems.
Now for the first question and its relation to global climate change. The Earth is a dynamic energy system that is driven by the Sun heat energy falling on the planet. While much of this energy is reflected back into space by clouds, ice cover and re-radiated by infrared heat exchange with deep space, an increasing percentage is being absorbed by the atmosphere (the carbon dioxide and methane green house gases) which means the atmosphere is getting warmer near the surface. The exposed oceans, no longer covered by ice, are also increasing in temperature, as is the land mass, especially in regions where surface albedo is increasing via changes in forest or snow coverage.
The global climate changes are complex, but generally all this increased heat energy leads to higher wind speeds, localized changes in atmospheric moisture leads to more intense storms and, overall the entropy, or disorder of the Earth’s climate system increases. With greenhouse gas emissions continuing to rise, it is clear from the laws of thermodynamics that weather storm systems will generally increase in intensity. Apart from reducing emissions, it seems that either a better method of predicting severe weather has to be developed, or we perhaps have to expect to have more incidents of aircraft damage or crashes in violent storm events.
Trevor Williams is a University of Victoria Mechanical Engineering PhD candidate specialising in renewable energy, power grid modelling and plug-in hybrid electric vehicles. He has a bachelors in Aeronautical Engineering, a Masters in Management Science and over 23 years international experience in the space industry, having worked on Earth observation and telecommunications satellites. He is the author of the Eco-Geek blog.
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