Frequency of severe air turbulence could triple due to climate change
Finding suitable flight paths to avoid turbulence is also becoming increasingly challenging for airlines as warming temperatures create larger storms and as the jet stream shifts northward, making instances of turbulence stronger and more frequent, says a U.K.-based scientist.
“The best scientific evidence is that there is a strong link between climate change and clear air turbulence,” said Paul Williams, a professor of atmospheric science at the University of Reading in the U.K.
“When someone says global warming, we think about the fact that it’s getting warmer,” he said. “And that’s true, it is, but the climate is changing in the upper atmosphere as well.”
According to research conducted by Williams, the type of “severe clear air turbulence” experienced by passengers aboard Air Canada flight AC33 Thursday – which resulted in an emergency landing at Honolulu’s international airport and sent 37 people to hospital – could double or even triple as carbon dioxide levels in the atmosphere rise.
WATCH: Climate change could lead to triple frequency of severe air turbulence
That’s because more C02 means warmer temperatures, which means shifting wind patterns with stronger and less predictable airflow, Williams said. This also means occurrences of severe clear air turbulence will become more common.
“Basically, the atmosphere can’t contain the stresses and strains and it becomes unstable and breaks down,” Williams said. “That’s how clear air turbulence is generated.
“The special thing about severe (clear air turbulence) is that it’s stronger than gravity,” he said. “So the vertical motions will be happening more rapidly than gravity. If you’re not seatbelted, or any objects are not secured, they will become catapults.”
But unlike turbulence caused by storms, which are visible by pilots, radar and satellites, clear air turbulence is impossible to see, Williams said. It’s also difficult to predict,
“The plane went out from under us and then boom we were up in the air,” said Sharon Thornton a passenger who was on board AC33 Thursday. “It’s very scary, I’ve never had that happen before and I’ve flown a lot all over the world.”
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And while there are tools used by airlines for forecasting this type of occurrence – tools Williams helped develop – these methods are only about 75 to 80 per cent accurate, he said.
“Forecasts are not 100 per cent perfect,” Williams said. “They are useful, and pilots and flight planners use them, but sometimes they just miss or fail to forecast a turbulence pattern.”
Climate change is shifting flight patterns
Increased turbulence isn’t the only effect climate change is having on air travel.
According to a 2017 study competed by Williams and fellow U.K. researchers, the shifting jet stream also means flights between Europe and North America are getting longer, while flights in the opposite direction are getting shorter.
The study looked at winter flights between London’s Heathrow airport and New York’s JFK airport. In many cases, flights returning from the U.K. took 10 to 15 minutes longer when compared to periods where the jet stream was weaker.
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In one case detailed in the study, Williams said an eastbound flight to London from New York took just five hours and 16 minutes to complete the journey. At the time, this was the non-Concord record for the fastest flight between the two cities. Meanwhile, two westbound flights to New York had to stop and refuel in Maine because the 400 km/h headwinds from the jet stream were so strong that the flights took much longer than expected.
“The headwinds were so strong and they were making so little progress that they didn’t have enough fuel to make it all the way to New York safely,” he said.
In total, the study predicted increased flight time caused by shifting wind patterns could amount to roughly 2,000 hours annually for transatlantic crossings. This, in turn, could cost airlines as much as $22 million a year in increased jet fuel costs and release the equivalent of 7,000 homes worth of C02 into the atmosphere each year.
Williams also warns there could be potential impacts on coastal airports caused by climate change. For example, stronger winds, storm surges, and rising sea levels could threaten runways, while warmer temperatures are likely going to make taking off more difficult because of weight restrictions and the physical limitations of airplanes in hotter climates.
In terms of turbulence – and in the wake of Thursday’s Air Canada flight – Williams thinks regulators around the world may want to consider stricter rules for the use of seatbelts on planes.
While it’s common practice for airlines – including Air Canada – to remind passengers to keep their seatbelts fastened at all times when seated – even when the seatbelt sign is off – Williams believes stricter rules could help prevent future injuries when turbulence occurs.
“If you’re driving down the road in your car at 10 miles an hour you need to be seatbelted. That’s the law,” Williams said. “But if you’re flying through the air at 35,000 feet and at 600 miles an hour, well it’s kind of optional unless the seatbelt sign’s on.
“That doesn’t quite make sense to me,” he said.
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