Climate change to make flying a rougher ride

Planet Earth online, 8 April 2013, by Alex Peel

'Fasten seatbelt' signs could become a more regular sight on transatlantic flights over the coming decades, scientists say.

New research, published in Nature Climate Change, says rising concentrations of CO2 in the atmosphere will increase the likelihood of hitting air turbulence by between 40 and 170 per cent.

Turbulence will also be between 10 and 40 per cent more intense, it suggests.

The study was led by Dr Paul Williams, based at the University of Reading, for NERC's National Centre for Atmospheric Science.

'Aviation is partly responsible for changing the climate in the first place,' he says. 'It is ironic that the climate looks set to exact its revenge by creating a more turbulent atmosphere for flying.'

The study used computer models to simulate how increasing CO2 concentrations will affect turbulence in the busy flight corridor between North America and Europe.

'Our research focused on clear-air turbulence in the winter,' explains Dr Manoj Joshi, of the University of East Anglia, who co-authored the study. 'This is especially problematic to airliners, because clear-air turbulence is invisible to pilots and satellites, and winter is when it peaks.'

Clear-air turbulence is caused by disturbances in air flow which are particularly common within jet streams, narrow rivers of fast-flowing air in the Earth's atmosphere.

Such a jet stream flows above the North Atlantic between North America and Europe, often making for bumpy flights between the two.

But Williams points out that the consequences of turbulence go beyond unwelcome butterflies in passengers' bellies.

'Air turbulence does more than just interrupt the service of in-flight drinks,' he says. 'It injures hundreds of passengers and aircrew every year - sometimes fatally. It also causes delays and damages planes. The total cost to society is about £100 million each year.'

'Re-routing flights to avoid stronger patches of turbulence could increase fuel consumption and emissions of atmospheric pollutants, make delays at airports more common, and ultimately push up ticket prices.'

Air turbulence can also be caused by storm clouds and interactions between the atmosphere and mountains. Those influences were not investigated in this study but may also be susceptible to climate change.

Williams PD, Joshi MM, Intensification of winter transatlantic aviation turbulence in response to climate change, Nature Climate Change, 2013, DOI:10.1038/NCLIMATE1866