Global warming over the past 40 years has greatly affected the speed and strength of air flows in the atmosphere, British meteorologists have found out. These processes threaten to increase turbulence and increase the number of accidents.
Climate change threatens not only biodiversity, taiga forests and polar ice – it also has effects that are closer and more understandable to humans. Meteorologists from the British University of Reading found that global warming has a negative impact on the safety and comfort of air travel.
Air temperature directly affects the characteristics of the so-called jet stream – a narrow belt of strong wind that meanders between the Earth’s poles and the tropics at or slightly below the flight altitude of aircraft. The wind and temperature in the atmosphere are in balance: it is impossible to change the temperature without causing a change in the nature of the winds.
However, in previous years, many researchers noted that the wind speed inside, for example, the North Atlantic jet stream has not changed much over the decades. The fact is that climate change affects the speed of the current in two opposite ways:
- in the upper layers of the atmosphere, climate change increases the movement of heat from the equator to the Earth’s pole (perpendicular to the wind), accelerating the high-altitude jet stream;
- in the lower atmosphere, the polar amplification of climate change, on the contrary, carries heat from the poles to the equator, weakening the opposite vector and slowing down the jet stream.
The struggle of these two movements above and below the jet streams helps to balance their speed. However, most studies, say meteorologists from the University of Reading, do not pay enough attention to another factor – vertical wind shear.
Wind shear is a sudden change in wind speed or direction over small areas in the atmosphere. The authors of the report specifically consider jumps in wind speed in the vertical plane. These phenomena can be potentially dangerous for aviation: for example, vertical wind shear is the official cause of the Tu-154 crash near Alma-Ata in 1980, when 166 people died. The Soviet aircraft crashed shortly after takeoff due to a violent downdraft (combined with other minor factors).
At altitude, vertical wind shear is one of the causes of turbulence, which creates additional difficulties for pilots. Not at the surface of the Earth, but higher, at the level of aircraft flight, horizontal wind shears occur more often, while vertical shears at such a height are characteristic of jet streams.
After analyzing satellite images and data from three different sources, British meteorologists found that vertical wind shear in the North Atlantic jet stream has increased by 40% over the 1979 years since 15. This happened precisely because of global warming, the authors of the report are sure: the above vectors of warming from the poles and to the poles, although they retained a balance, but noticeably increased, affecting what happens inside the wind flow. If no action is taken to combat climate change, transatlantic travel will become less and less enjoyable with each passing decade, they warn.