As more and more phone footage shows, terrifying air turbulence can hurl people through an aircraft cabin, causing serious injury and even death.
Unfortunately, a new study led by the University of Chicago warns that these types of events could become even more common – and that it's due to climate change.
The authors say that global warming is accelerating winds in the jet streams, due to changes in the density of air in Earth's atmosphere.
These higher wind speeds cause heavier updrafts and downdrafts, resulting in severe turbulence for aircraft.
We already know that global warming and severe turbulence have increased simultaneously since the 1970s, but the new study identifies cause and effect.
Jet currents are created by the contrast between cold, dense air at the poles and warm, light air in the tropics, combined with the Earth's rotation. The new study shows that climate change reinforces this contrast. Pictured: jet stream winds (dark red), which will become faster due to climate change
The new study was led by researchers from the University of Chicago and the National Center for Atmospheric Research.
“Based on these results and our current knowledge, we expect record winds,” said Professor Tiffany Shaw of the University of Chicago.
'It is likely that they will contribute to shorter flight times, increased clear-sky turbulence and a possible increase in the number of severe weather events.'
Jet streams are powerful, narrow winds in the upper atmosphere that drive much of Earth's weather systems and are associated with outbreaks of severe weather.
They usually move from west to east around the world in the upper atmosphere, about six miles above the ground.
Jet currents are created by the contrast between the cold, dense air at the poles and the warm, light air in the tropics, combined with the Earth's rotation.
By combining models of climate change with what we know about the physics of jet streams, the researchers found that climate change amplifies this contrast.
As the air in the tropics continues to warm, it will retain much more moisture.
Severe turbulence can cause sudden changes in aircraft altitude and nasty injuries (file image)
As the air in the tropics continues to warm, it will retain much more moisture. Although the air at the poles will also warm, warmer air can hold much more moisture than cold air, greatly increasing the overall density difference
Although the air at the poles will also warm, warmer air can hold so much more moisture than cold air that the overall density difference only increases sharply – causing fast winds in the jet stream to become faster.
As the world warms, the fastest upper-level jet stream winds will become increasingly faster — by about two percent for every degree Celsius the world warms, the study authors estimate.
Scientists already know that a potential positive effect of the jet stream is faster flights, depending on the direction a plane is flying.
Airplanes can 'surf the wind' to get a speed boost and reduce flight times, while also using less fuel and in turn reducing CO2 emissions.
A University of Reading study found that commercial transatlantic flights could use up to 16 percent less fuel if they made better use of fast-moving winds.
While faster transatlantic flights may not seem so bad, the downside is that planes are likely to experience more turbulence.
For commercial aircraft, today's most problematic type of turbulence – known as clear-air turbulence (CAT) – is invisible.
CAT is difficult to observe ahead of an aircraft's trajectory using remote sensing methods and challenging for aviation meteorologists to predict.
Diverting transatlantic flights to better take advantage of favorable high-altitude winds could save fuel, time and emissions
A study by the University of Reading has shown that aircraft can reduce their CO2 emissions by piggybacking on the jet stream more often
In addition, jet streams strongly influence the weather on the ground, including the most severe weather conditions.
“Jet currents are important because they determine Earth's surface climate by directing weather systems and are associated with severe weather events,” the experts say in their paper.
“In particular, the regions surrounding high-speed, higher-level jet stream winds have been associated with the occurrence of severe storms, tornadoes, hail and high winds.”
The team calls for more research to predict exactly how these faster winds will affect individual storms and severe weather events.
The new study has been published in the journal Nature Climate change.