GabyClimate change is causing many unpleasant and sometimes unexpected effects. Strong turbulence is increasing alongside global warming. British scientists have found that since 1979 severe turbulence over the North Atlantic has risen by 55%, and the situation may worsen further.
Threats from turbulence
Turbulence is an unpleasant phenomenon well known to pilots and frequent flyers. It causes sudden drops in altitude, which can lead to injuries and even fatalities. During turbulence, forces greater than gravity can act on passengers and luggage. Those forces are what cause luggage to fall out of overhead bins and people to shift suddenly in their seats.
Tens of thousands of airliners encounter severe turbulence every year. Airlines spend up to $1 billion a year repairing structural damage, compensating injured passengers, and covering flight delays.
Aircraft turbulence most often occurs in clearly defined areas (for example, over mountain ranges). In many cases, pilots and dispatchers can therefore avoid it.
However, clear-air turbulence (CAT) is a special type that is difficult to detect. It occurs when air masses moving at different speeds meet. This turbulence is hard to observe along a flight path with remote sensing and very challenging for aviation meteorologists to predict.
Professor Ramalingam Saravanan, who specializes in atmospheric research, says the main problem with CAT is that it cannot be seen. The phenomenon involves sudden changes in wind speed at high altitudes.
Only pilots who have encountered clear-air turbulence (CAT) can warn other crews and report its location. Saravanan says CAT can be predicted statistically, but not in individual cases, because the process is essentially random.
Research in the relationship between turbulence and climate change
After a decade of study, scientists have found that climate change is leading to an increase in clear-air turbulence, and the trend is accelerating. The Daily Mail’s Mark Prosser reports that researchers analyzed atmospheric data—from pilot reports and satellite observations—for the period 1979–2020, focusing on air temperature and wind speed.
According to the research, the total annual duration of severe turbulence over the North Atlantic increased by 55% from 1979 to 2020. Moderate turbulence rose by 37%, while light turbulence climbed 17%.
The largest increases in turbulence were observed over the United States and the North Atlantic. Other busy routes over Europe, the Middle East, and the South Atlantic also showed rises. The increase in turbulence in the Northern Hemisphere is higher than in the Southern Hemisphere, a pattern the researchers say requires further investigation.
The researchers call their study “the best evidence to date” that clear‑sky turbulence has grown in recent decades along with global warming. If emissions are not reduced, CAT could become two to three times more frequent. Earlier work from 2017 indicates the most significant global increases in clear‑air turbulence will occur between 2050 and 2080.
How exactly does global warming make clear‑air turbulence worse?
Scientists say the rise in invisible, dangerous clear‑air turbulence is tied to global warming: the two trends are connected.
Clear‑air turbulence is created by wind shear—sudden changes in wind speed or direction. The troposphere is the lowest layer of the atmosphere, with the stratosphere above it. As greenhouse gases increase, the troposphere tends to warm while the stratosphere cools.
That contrast increases the vertical temperature difference in the atmosphere, which strengthens and destabilizes air currents. Stronger, more wavy jet streams form as a result.
Commercial airplanes typically cruise in the jet streams—fast-moving rivers of air high in the atmosphere. When those streams become more intense and meandering, planes are more likely to encounter clear‑air turbulence.
It’s better to prevent a problem than to deal with its consequences
Flight delays, lost luggage, and long lines at baggage claim are almost standard annoyances for air travelers. Now scientists warn of another, more serious problem: increasing encounters with dangerous turbulence.
Paul Williams, the lead author of the study, stresses the need to invest in better turbulence prediction and detection systems. It is far better to prevent disasters related to severe turbulence than to deal with their consequences. Policymakers and aviation authorities should consider that turbulence is likely to intensify in the coming decades.
