Climate change could make severe turbulence even worse

Airplane passengers are in for an increasingly bumpy ride according to a study released today in the journal Advances in Atmospheric Sciences. Climate change is altering the jet stream, making severe turbulence more likely. The study builds on earlier work which found that climate change would lead to bumpier airplane rides. What makes the new research unique is that it quantifies how much different kinds of turbulence will increase—59 percent in the case of light turbulence, a 94 percent increase in moderate turbulence, and 149 percent increase in severe turbulence.

For the one in four Americans who are afraid of flying, any jostling could be considered severe. But like an earthquake, turbulence is rated on a scale. One is light—gentle enough so passengers may not notice it—three is moderate, or enough to jostle a drink, five is severe, and seven is extreme.

"Anything above five is by definition stronger than gravity," says study autho Paul Williams, an atmospheric scientist at the University of Reading in the United Kingdom. "What that means is that anything that's not strapped in will potentially be projected around inside the plane. That would include passengers."

43 PHOTOS
The Boneyard, where US Air Force planes go to die
See Gallery
The Boneyard, where US Air Force planes go to die

Aircraft from all military services cover the desert landscape of the 309th Aerospace Maintenance and Regeneration Group "Boneyard" at Davis-Monthan Air Force Base, Ariz.

(Photo by Bennie Davis via U.S. Air Force)

An old, weathered flight manual sits inside the remains of a CH-3E Jolly Green Giant. After years of standing in the desert sun of the boneyard, aircraft and equipment slowly age and erode.

(Photo by Andrew Lee via U.S. Air Force)

The Boeing YAL-1 Airborne Laser Testbed, (formerly Airborne Laser) weapons system now sits decommissioned in the boneyard. The YAL-1 was primarily designed as a missile defense system to destroy tactical ballistic missiles with an airborne laser system.

(Photo by Bennie Davis via U.S. Air Force)

The cockpit section of a C-141 Starlifter sits dissected and strapped to the ground.

(Photo by Bennie Davis via U.S. Air Force)

The C-141 remained in service for over 40 years until the Air Force withdrew them from service in 2006 and replaced them with the C-17 Globemaster III.

(Photo by Bennie Davis via U.S. Air Force)

A fleet of C-5 Galaxies tower above the rest of the fighter and cargo aircraft inside the "Boneyard."

(Photo by Bennie Davis via U.S. Air Force)

Rows of F-4 Phantoms and T-38 Talons line the grounds.

(Photo by Bennie Davis via U.S. Air Force)

A rainbow peaks at the old unused fleet of F-4 Phantom fighters.

(Photo by Bennie Davis via U.S. Air Force)

The F-4 Phantom II served as the principal air superiority fighter for the Air Force during the Vietnam War, and became important in the ground-attack and reconnaissance roles late in the war.

(Photo by Andrew Lee via U.S. Air Force)

Retired Brig. Gen. Keith Connolly, a command pilot with more than 4,800 flying hours in F-86s, F-100s, A-7s, F-4s, F-15s and F-16s, stands before a retired F-4 Phantom.

(Photo by Bennie Davis via U.S. Air Force)

The F-4 Phantom II has the distinction of being the last U.S. fighter flown to attain ace status in the 20th century.

(Photo by Bennie Davis via U.S. Air Force)

More Phantoms, used, abused, and now wholly unused, except by possibly the occasional critter.

(Photo by Bennie Davis via U.S. Air Force)

The remains of a B-66 Destroyer sit palletized. The aircraft was a light bomber with the Tactical Air Command and the RB-66 models were used as the major night photo-reconnaissance aircraft for the Air Force during the 1950s.

(Photo by Bennie Davis via U.S. Air Force)

Another F-4 Phantom surrounded by the twilight of a falling sun.

(Photo by Andrew Lee via U.S. Air Force)

There is little rust and metal detrioration in the arid Arizona desert, making it the perfect place for the Air Force's only aircraft "boneyard."

(Photo by Bennie Davis via U.S. Air Force)

The Air Force "Boneyard" is at a secure location in Ariz. The facility is seldom seen by the public, outside of local bus tours and as a backdrop of Hollywood movies and television shows.

(Photo by Bennie Davis via U.S. Air Force)

Ripped and torn pieces of the fuselage are all that remain of a C-5 Galaxy after being torn apart by an excavator crane for scrap.

(Photo by Bennie Davis via U.S. Air Force)

The boneyard is basically a 2,600-acre parking lot and storage facility for about 5,000 retired military aircraft.

(Photo by Bennie Davis via U.S. Air Force)

The remains of a C-5 Galaxy rise six stories into the night sky.

(Photo by Bennie Davis via U.S. Air Force)

Tails of decommissioned aircraft sit against the backdrop of a setting sun.

(Photo by Bennie Davis via U.S. Air Force)

A C-5 Galaxy, its wings stripped to the frame, is undergoing a complete tear-down of all important parts before being demolished for scrap, a process that takes nearly a year to complete.

(Photo by Bennie Davis via U.S. Air Force)

Wings and parts are pulled from the C-5 Galaxy aircraft before the airframes are torn apart for scrap.

(Photo by Bennie Davis via U.S. Air Force)

The rows of F-15 Strike Eagles and F-16 Fighting Falcons undergo a preservation process that allows them to be recalled into active service within 72 hours if needed.

(Photo by Bennie Davis via U.S. Air Force)

A C-130 from the 43d Air Wing, Pope Air Force Base, N.C., peers deeper into the boneyard.

(Photo by Bennie Davis via U.S. Air Force)

The remains of a B-66 Destroyer seen through the shattered cockpit glass of an F-86 Sabre.

(Photo by Bennie Davis via U.S. Air Force)

The fuselage of an A-10 Thunderbolt II sits surrounded by the rest of its parts. Aircraft like this are typically used to provide parts to other A-10s still serving throughout the Air Force.

(Photo by Andrew Lee via U.S. Air Force)

Ret. Col. Paul Dillon, a vietnam combat pilot, stands with an A-10 Thunderbolt II. The jet is one of the many airframes the colonel flew while in the Air Force. Dillon is wearing his 469th Tactical Fighter Squadron flightsuit from his duty in Vietnam were he flew interdiction operations in North Vietnam and Laos.

(Photo by Andrew Lee via U.S. Air Force)

The Phantom sits, still somewhat preserved. Still visible are the influences of it's predecessor, the F-8 Crusader.

(Photo by Andrew Lee via U.S. Air Force)

Interminable rows of dismantled KC-135 Stratotanker stretch into the desert. The Air Force still actively fields hundreds of these for refueling purposes.

(Photo by Bennie Davis via U.S. Air Force)

A C-5 Galaxy waits to be broken down and turned into scrap metal — The 309th Aerospace Maintenance and Regeneration Group then sells the scrap metal to other customers.

(Photo by Andrew Lee via U.S. Air Force)

High above the ground, a C-5 Galaxy aircraft sits motionless as clouds pass by. The Galaxy used to be the Air Force's premier military transport aircraft.

(Photo by Andrew Lee via U.S. Air Force)

The North American F-86 Sabre was a transonic jet fighter aircraft mainly used during the Korean War and the early parts of the Cold War era.

(Photo by Andrew Lee via U.S. Air Force)

The B-66 Destroyer was a U.S. Air Force Tactical Air Command light bomber. The RB-66 models were used as the major night photo-reconnaissance aircraft of the USAF during the 1950s.

(Photo by Andrew Lee via U.S. Air Force)

Cracked and rusted gauges from an old blimp show the signs of sitting unused for decades.

(Photo via Andrew Lee via U.S. Air Force)

A UH-34D Seahorse helicopter, which began service in 1952 as a Navy anti-submarine warfare helicopter and served as the primary Marine Corps assault helicopter of the Vietnam War. This one now sits as part of the more than 4,400 deactivated aircraft.

(Photo by Andrew Lee via U.S. Air Force)

Inside the belly of the blimp.

(Photo by Andrew Lee via U.S. Air Force)

Marilyn Savage, widow of Lt. Col. Robert Savage, joined the Air Force in October of 1951 and was discharged in 1953 as a sergeant. She is a past president of the Society of Military Widows and has been a member of the group for more than 20 years. Her husband piloted the F-84 Thunderjet similar to the one behind Marilyn.

(Photo by Andrew Lee via U.S. Air Force)

A retired, rusted, faded T-38 Talon sits in pieces. The Talon was the world's first supersonic trainer.

(Photo by Andrew Breese via U.S. Air Force)

The T-41 Mescalero was the military version of the popular commercial Cessna 172. Rows of them sit in the boneyard.

(Photo by Andrew Breese via U.S. Air Force)

The "Boneyard" hosts civilian aircraft as well, like this commercial cargo plane.

(Photo by Andrew Breese via U.S. Air Force)

A set of pilot seats are all that remain of an unidentified aircraft.

(Photo by Andrew Breese via U.S. Air Force)

If anything, the graveyard serves as a grim reminder of the necessities for military air power.

(Photo by Andrew Lee via U.S. Air Force)

HIDE CAPTION
SHOW CAPTION
of
SEE ALL
BACK TO SLIDE

Shake, Rattle, But No Rolls

Turbulence happens when an air mass moving at one speed meets another air mass moving at a different speed. The meeting causes a sudden shift in airflow, leading air to move chaotically. It's a bit like trying to walk down the street on a particularly windy day, and being buffeted about in multiple directions. So, a plane moving into turbulent air may have its left wing hit by an upward gust causing the plane to bank right. Similarly, if both wings are suddenly hit by a downward gust, the whole plane might drop a bit, which isn't great for anyone inside.

Last October, an Air New Zealand flight from Ho Chi Minh to Auckland encountered turbulence so severe it was forced to turn around after two crew members suffered critical injuries. That same year, a JetBlue flight from Boston to Sacramento was forced to make an unplanned landing after it hit a patch of turbulence that sent 22 passengers and 2 crew members to the hospital. In 2015, an Air Canada flight from Toronto to Shanghai experienced turbulence that led to the injuries of 21 people. The plane made an emergency landing in Calgary, Alberta. And in 2014, a United Airlines flight from Denver to Billings, Montana hit turbulence so severe that five people went into the hospital.

Satellite observations dating back to the 1970s show that because of climate change, different parts of the atmosphere are warming up at different rates. At 30-40,000 feet, the low latitude tropical regions are warming much faster than the high latitude arctic regions (which is the opposite of what's happening on the ground). This temperature difference has always driven the jet stream, but as tropical regions warm up faster than the arctic, that difference grows—and the jet stream becomes both stronger, and less stable. Turbulence is coming along for the ride.

"Turbulence can actually damage planes," said Williams. "There was a plane flying over the Colorado Rocky's on the 9th of December 1992 through some extreme clear air turbulence—it would have been a seven [on the scale]. Six meters of the left wing broke off and one of the engines got torn off as well."

Plane engines, Williams told PopSci, are affixed with aptly named, 'shear nuts and bolts.' The engines are designed to shear off planes if they become unstable. "The fact that the engine broke off probably saved the life of the people on the plane, because the last thing you want is an unstable engine kind of hanging off a plane causing instabilities."

This kind of damage is rare—in most cases turbulence is still more about comfort than safety, and there hasn't been a single plane crash due to turbulence since the 1960s. But even light and moderate turbulence will cause wear and tear on a plane. That means the need for inspections—for planes to be taken out of service and maintained—will also go up. It's a significant economic burden for an industry already operating on razor thin margins.

While the seasoned traveler may wonder why pilots don't just fly around the turbulence, the answer is simple: the pilots can't see it. Though we tend to think of turbulence as being associated with storms, the kind of turbulence Williams focuses on is related not to weather but to the jet stream, or the bands of strong wind in the upper levels of the atmosphere.

"We call it clear air turbulence to distinguish it from the other kinds of turbulence which is in clouds," said Williams. "The pilot can see the clouds, so he or she knows that the turbulence will be there and will avoid trying to fly through. But clear air turbulence is particularly hazardous precisely because it's invisible. It tends to strike when the seatbelt light is switched off and passengers are moving around inside the cabin." On average, patches of clear air turbulence tend to be more than half a mile tall (3,280 feet) and 37 miles wide.

Predicting Turbulence

Williams was able to predict increases in turbulence by running a climate model. He ran it first under control conditions, using preindustrial levels of carbon dioxide for the equivalent of twenty years. He then ran a second simulation where the CO2 is double that of the pre-industrial levels—roughly where we'll be by the middle of the century if we don't change our behaviors.

But climate models don't actually have this kind of turbulence built into them. "Williams took 21 vetted, commonly used indicators for turbulence and looked for those in the climate model," said Kristopher Karnauskas, a researcher in the Department of Atmospheric and Oceanic Sciences at the University of Colorado Boulder who was not involved in the study. "It's not just limited to one predictor of turbulence, because no one predictor of turbulence is perfect or always right, so he used a broad ensemble approach."

Williams then compared the control run with the elevated CO2 condition and calculated the amount of turbulence in both of them. That's how he found the increases.

graph of turbulence increase

Climate change will increase turbulence by a lot.

Why Models Matter

Climate models have come under fire recently, in part because to lay people they can seem disconnected from reality. That's why Karnauskas likes to use TV screens to explain how they work.

"With a climate model, you take the planet and you cut it up into grid cells like the pixels on a TV," Karnauskas. "Each of those grid cells knows all the laws of physics. It looks at its neighbors around it and says 'is it warm over there, is the wind coming from this direction, and then it marches forward in time." By being fed those base conditions, the model can make extrapolations about the future.

In fact, the only limitation of the study that Karnauskas notes is that it only uses one climate model, which he says limits our ability to categorize the full certainty of the results. But this isn't the first study to suggest that the jet stream is changing along with the warming climate.

Both Williams and Karnauskas have published studies that found that because the jet stream is getting stronger, eastbound flights from the U.S. to Europe will get faster, while westbound flights from Europe will be slower. This is backed up by real world incidents.

In January 2015, a flight from New York's JFK airport to Heathrow took only 5 hours and 16 minutes because the jet stream was so strong. Ordinarily, that flight takes longer than six hours. During that same period, westbound flights from London and Paris to New York battled such strong heads that they burned more fuel than expected, requiring stops in Maine for refueling

It's important to note that Williams' study only looked at the North Atlantic—its conclusions can't be extrapolated for other routes. At the same time, however, it's important to recognize the impacts that climate change will have on the aviation industry so that companies can better plan and prepare for everything from plane maintenance and repair to fueling.

"For decades, all of the focus on climate change and air travel was about how air travel is going to make climate change worse," said Karnauskas. "But this kind of study, and other studies around climate change making flight times longer, are a new wave of looking at that relationship. It's showing that climate change can feed back on the industry itself. It's not just that air travel affects climate—we know that's true. But air travel is being affected by climate change."

Read Full Story

Sign up for Breaking News by AOL to get the latest breaking news alerts and updates delivered straight to your inbox.

Subscribe to our other newsletters

Emails may offer personalized content or ads. Learn more. You may unsubscribe any time.