Yes, turbulence is getting worse — and it isn’t your imagination. At a representative point over the North Atlantic, the annual duration of severe-or-greater clear-air turbulence rose from 17.7 hours in 1979 to 27.4 hours in 2020. That’s a 55% increase.
The driver is strengthened wind shear, not storms. For passengers, the main takeaway is defensive: keep your seatbelt fastened, because the most dangerous turbulence is the kind no one sees coming.
The number sounds like a passenger complaint. It isn’t. When researchers at the University of Reading analyzed decades of atmospheric reanalysis data for a single point over the North Atlantic, they found that the time spent in severe-or-greater clear-air turbulence each year climbed from 17.7 hours in 1979 to 27.4 hours in 2020. That’s a 55% increase, measured, not remembered.
This is not a forecast. It’s a record of what already happened. The mechanism behind it is well understood: climate change is strengthening the jet stream’s vertical wind shear, and that shear is the factory floor for clear-air turbulence. Because clear-air turbulence forms without clouds, pilots can’t see it, and onboard radar can’t paint it. The aircraft simply hits a patch of invisible violence.
That has costs. Injuries, lawsuits, operational disruption. And the Southern Hemisphere, where many long-haul routes cross, remains a research blind spot. This piece walks through the measured trend, the physics, the injury economics, and what airlines are doing about it — which, for now, is mostly forecasting and hoping.
Clear-air turbulence: what you can’t see can hurt you
Clear-air turbulence is the surprise visitor at cruising altitude. Unlike the bumps you get when flying through a storm cell, clear-air turbulence forms in clear skies, where there are no clouds to warn you and no radar echoes to show a pilot. It is driven by unstable waves breaking in strongly sheared wind fields — a process called a Kelvin-Helmholtz instability — but the basic point is simpler: high-altitude wind speed changes create invisible pockets of violent air.
The best-measured corridor is the North Atlantic. Using ERA5 reanalysis data from 1979 to 2020, researchers found that at a typical point, the total annual duration of severe-or-greater CAT rose from 17.7 hours to 27.4 hours. That is the 55% increase you’ll see quoted. The same dataset shows moderate-or-greater CAT up 37% and even light-or-greater up 17% — so the trend is not just about the worst events; the overall exposure is climbing.
Why the North Atlantic? It’s a dense air corridor between North America and Europe, with decades of consistent atmospheric data. Most transatlantic travelers cross this exact airspace.
Why wind shear at cruising altitude is climbing
The cause is wind shear — the change in wind speed or direction with altitude. At cruising altitude, the jet stream shears like a knife edge, and that shear is getting sharper. Three independent atmospheric reanalysis datasets agree: vertical wind shear at aircraft cruising altitudes has strengthened by about 15% since 1979.
Climate models project this trend continuing. By 2100, upper-level jet-stream wind shear could climb another 17–29%, depending on emissions. That translates into a two- to threefold increase in severe clear-air turbulence frequency by the end of the century. The physics is not controversial: a warmer troposphere and a cooler stratosphere tighten the vertical temperature gradient that drives the jet stream, making the shear more extreme.
One point often missed: this is not a global average that hides regional variation. The mechanism operates wherever strong jet streams exist, but different corridors will see different rates. The North Atlantic happens to have the best historical record, which is why it carries the headline number.
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The injuries and costs no one totals up
When clear-air turbulence hits, the injuries are real and concentrated. Flight attendants are the front line. In US government data, roughly 78–80% of serious turbulence injuries since 1989 have involved crew, making flight attendants about 24 times more likely than passengers to be hurt. A ten-year FAA count from 2007 to 2016 recorded 424 serious injuries from in-flight turbulence. Since 2009, the NTSB has logged 207 severe injuries, and 166 of those were crew.
The legacy figure often cited in media — 560 passengers and 1,500 flight attendants injured per year — comes from older studies and cannot be linked to any current primary dataset. The better numbers are smaller but still sobering: turbulence remains the most frequent accident category in recent global reports.
Then there’s the money. For US airlines alone, one FAA-cited study put turbulence-related losses at about US$100 million a year. The National Center for Atmospheric Research’s wider estimate runs US$150–500 million, once you include injuries, aircraft damage, delays, inspections, and maintenance. One 2018 review added another line: over US$10 million a year in injury compensation and more than 7,000 lost working days for cabin crew.
The high-profile events are just the visible tip. When Singapore Airlines SQ321 hit severe turbulence over Myanmar in May 2024, one passenger died and 56 were seriously injured — a classification confirmed in the Paddy You’re Own Kanoo report. Scientific reconstruction of the event, published in Nature Scientific Reports, found cloud tops near 55,000 feet and updrafts of 8,000–9,000 feet per minute, with G-forces around 1.15 g. That’s well below structural limits, but it’s enough to throw unbuckled passengers into the ceiling.
An Air Europa Boeing 787 en route from Madrid to Montevideo in July 2024 hit severe turbulence and diverted to Natal, Brazil, with about 30–40 passengers needing hospital treatment for fractures and cranial trauma.
Forecasts get better, but detection still lags
Four times a day, the World Area Forecast Centres in London and Washington issue global turbulence forecasts built on diagnostics that blend wind shear, temperature gradients, and numerical weather prediction. Airlines use them to plan flight paths and adjust altitudes. But these are probabilities, not precise warnings. A forecast can say “moderate or greater turbulence possible over this region,” but it cannot tell a pilot that at 37,000 feet over 55°W there is a 10-mile patch of severe CAT.
Data sharing is improving. IATA’s Turbulence Aware platform grew from more than 25 airlines and 2,600 aircraft in late 2024 to 28 airlines and roughly 2,700–2,800 aircraft by mid-2025. In the first six months of 2025, participants generated 24.8 million turbulence reports, a 23% increase year over year. That’s a lot of real-time reports, but they still depend on an aircraft encountering turbulence before it gets reported.
NOAA is pushing toward near-real-time nowcasting. The Graphical Turbulence Guidance Nowcast, planned for July 2026, will use short-term model output to provide turbulence analyses every 15 minutes. That’s a meaningful step, but even a 15-minute lag is an eternity when you’re inside the patch. Airborne LIDAR concepts are in trials, but none are operational for passenger aircraft.
The Southern Hemisphere blind spot
Here’s what the data doesn’t show. The 55% figure is specific to the North Atlantic. No peer-reviewed study has published an equivalent trend for the South Atlantic, trans-Tasman, or Australia–South America corridors. The available reanalysis-based indicators show clear-air turbulence potential rising across global jet-stream zones, with the strongest measured increases over the North Atlantic and North Pacific. But when you board a flight from Sydney to Santiago, you’re flying through a corridor that researchers haven’t studied with the same long-term rigor.
That matters. The physics — strengthened wind shear in the jet stream — is not region-locked. Southern Hemisphere routes cross the polar-front jet just as northern ones do. The absence of a verified trend figure is not evidence of no trend; it’s a gap in the literature. Travelers on trans-Tasman or South America–Australia itineraries should assume the same underlying risk, not less.
The Mechanism: How a clear sky turns hostile
The underlying instability is a textbook phenomenon. When wind speed changes rapidly with altitude, the boundary between those layers can roll into breaking waves, called Kelvin-Helmholtz billows. At aircraft cruising altitudes, the jet stream provides exactly that kind of strong shear. As the waves break, they create pockets of chaotic vertical motion — the airplane hits one and drops, climbs, or shakes violently. There are no clouds because the air is clear; the instability is invisible to the eye and to conventional weather radar, which detects precipitation, not wind shear.
The 55% figure comes from a 2023 Geophysical Research Letters analysis of ERA5 flight-level data. It remains the newest peer-reviewed estimate; through early 2026, no study has revised or replaced it. Later attribution and regional climatology work continues to cite it as a benchmark. That’s rare in climate science, where estimates get adjusted with each new reanalysis. The number has staying power.
What this means for you
Here’s the practical bottom line. On any long-haul flight, the baseline odds of encountering severe clear-air turbulence are higher than they were in 1979, and the event itself gives no visual warning. Flight attendants are the ones standing and lifting bags when the invisible patch arrives, which is why they absorb roughly 80% of serious injuries.
The best defense is a seatbelt. Not just during the sign. Even when the sign is off, keep it loosely fastened if you’re seated. That one habit turns a “ceiling strike” into a rough ride. It doesn’t eliminate the risk, but it addresses the most common mechanism of serious injury: being unbuckled during abrupt vertical motion.
Operationally, airlines are getting better at avoiding the worst regions through four-times-daily forecasts and crowd-sourced turbulence reports, but they still cannot see clear-air turbulence in real time. The Graphical Turbulence Guidance Nowcast, if it works as planned in 2026, will narrow that gap. For now, treat any clear-sky bump as a warning that the next one could be bigger.
Questions? Answers.
Can turbulence bring a plane down?
Modern airliners are engineered to withstand forces far greater than those recorded in severe clear-air turbulence. Scientific reconstruction of the SQ321 event measured G-forces around 1.15 g, well below structural limits. The documented consequences are injuries and financial costs — over US$10 million per year in turbulence injury compensation and more than 7,000 lost crew work days.
What flight path has the worst turbulence?
The North Atlantic corridor has the strongest verified long-term trend. At a typical point, severe-or-greater clear-air turbulence rose 55% from 1979 to 2020. Moderate-or-greater potential increased by 61.8% in the northern North Atlantic and 155.9% in the southern part, based on multiple reanalysis datasets.
