Climate change poses air turbulence risk (online headline)
Atlantic air routes likely to be more turbulent (print headline)

Financial Times
April 8, 2013 3:01 pm (online) | April 9, 2013 (print)
By Pilita Clark, Environment Correspondent

Climate change has over the years been blamed for a host of biblical occurrences from rising sea levels, fires and floods to droughts. Now scientists say it is likely directly to affect business travellers on one of the world's busiest routes.

The risk of aircraft running into air turbulence on transatlantic routes is likely to double because of global warming in coming years, according to research published on Monday.

The strength of the bumpiness is also likely to increase and, while it is not likely to send aircraft routinely crashing to the ground, it could put passengers and crew at more risk and force airlines to reroute flights.

That could aggravate airport delays, increase fuel consumption and ultimately even push up ticket prices, according to the authors of what is said to be the first study to investigate the link between turbulence and climate change.

"Our research suggests that we'll be seeing the 'fasten seat belts' sign turned on more often in the decades ahead," said one author, atmospheric scientist Dr Paul Williams, of the University of Reading.

"It's kind of surprising no one has thought about studying this before," he said, adding that turbulence at cruising altitudes injures hundreds of passengers each year, sometimes fatally, and costs airlines millions of dollars in damaged aircraft.

"Broken skulls are a very common injury," he said. "Doing this research has changed the way I fly. I certainly keep my seatbelt fastened all the time now even when you are not required to."

Dr Williams explained that the reason the problem is likely to grow worse is because climate change does not just warm the lower part of the atmosphere where humans live. It also accelerates the jet stream, a gigantic fast-moving body of air that circulates several kilometres high. This acceleration makes the atmosphere more susceptible to the instability that creates turbulence.

Dr Williams and his co-author, Dr Manoj Joshi of the University of East Anglia, used computer models to calculate how this instability was likely to change as levels of carbon dioxide in the atmosphere increased. Carbon dioxide is the main greenhouse gas produced by human activities such as burning fossil fuels such as coal and oil.

The scientists found that by the middle of the century, the chances of an aircraft encountering significant turbulence on transatlantic routes would increase by between 40 per cent and 170 per cent. The most likely result was a doubling of the amount of airspace likely to be subject to noticeable amounts of turbulence.

There was some evidence that this had already started to happen, Dr Williams said, though it was very speculative and tentative.

"The only ray of hope is if atmospheric scientists get better at predicting turbulence in advance, so that flights can be routed around it. Whether this is possible remains to be seen," he said.

The authors estimate turbulence costs society about $150m each year in total, because so many people were injured and aircraft damaged.

So far, they have only studied the risk of increasing turbulence for flights across the Atlantic, one of the busiest flight corridors in the world. In future, they hope to look at other regions.

British Airways said its pilots were trained to deal with turbulence and the airline invested heavily in equipment to help them avoid it.

"The technology on both the ground and onboard to predict, avoid and mitigate turbulence has improved hugely over the past 20 years and we would expect that pattern to continue into the future," BA said.

The study, "Intensification of winter transatlantic aviation turbulence in response to climate change", is published in the journal Nature Climate Change.