Surprising properties of contrails – TVN Meteo

Contrails are characteristic white clouds that form behind a flying aircraft. They are created when hot exhaust gases meet cold, moist air. Contrails can stay in the air for up to several hours.

A team of scientists from the University of Carlos III in Madrid decided to thoroughly investigate the properties of contrails and their impact on global warming. The results were published on the website in mid-September arXiv.

The study, using artificial intelligence, analyzed approximately 700,000 contrails from satellite images covering Europe, North Africa and the surrounding oceans. Filming covered two week-long periods in January 2023 and 2024.

The results suggest that contrails produced by planes during the day reflect sunlight back into space, producing a cooling effect. At the same time, they make it difficult to radiate heat cosmosbut this is much less important than limiting the heat flow from the Sun.

In turn, at night, when the Sun is not shining, contrails only block the radiation of heat by the heated Earth's surface, which promotes global warming.

The majority of cases observed in the study, 62%, were contrails that formed overnight, so the net effect of all contrails is a warming one. However, the study only looked at the Northern Hemisphere during winter, when nights are longer than days.

According to scientists, flights taking place during the day can reduce the impact of carbon dioxide emissions on global warming. On the other hand, some streaks can last for several hours, which means that their effect would be negative at night.

Another way to reduce the impact of contrails could be to direct planes to avoid areas with extremely humid air where contrails form – by flying higher or lower. However, this would involve extending the flight route and increasing fuel consumption.

The team plans to repeat the study at other times of the year to see if and how the plumes' overall impact on climate changes.