A new study about creation of further flight cirrus within already existing cirrus clouds increases the climate impact of aviation by previously unknown 10%
Seelig et al 2025: https://www.nature.com/articles/s41467-025-66231-8
A good German summary and explainer of why, when, and where flight cirrus are harming us https://www.scinexx.de/news/geowissen/klima-wie-versteckte-kondensstreifen-zur-erwaermung-beitragen/
So each ton of flight-CO2 is really worth 3.3t. Based on Lee et al 2021 – cited by the Seelig paper as well – who found that burning kerosene in high altitude has 3 times the warming impact over burning fossil fuels on the ground.
https://www.nature.com/articles/s41467-025-66231-8
I know only 1 CO2 calculator that correctly observes the tripling impact:
https://uba.co2-rechner.de/de_DE/calculator/flight/
Another thought: the aviation industry expects a 5% increase every year. And by the way, according to Atmosfair, most flights are not biz flights but private choices.
So with +5% each year, how will the cirrus impact evolve?
The number of passengers would double every 16 years. While it doesn't necessarily mean that the number of contrails doubles in 16 years as well, as it depends on number of machines in the air for doubled passenger numbers. But to put it mildly, doubling passenger count is not going to decrease contrails either.
I think, contrails have direct and disruptive impact on societies. Because they heat up night-time 2m temperatures locally by maybe 2°C compared to no cirrus. A heatwave gets that much more stressful. And the weather gets that much more angry energy to produce extreme events.
Dunno how much this occurs over oceans and what the impact there is. The ocean surface and low depths have such a long memory for temperature. What happens over the ocean stays in the ocean, so to speak.
The official EU petition for rationing flight-CO2 died today. See https://fedifreu.de/@anlomedad/115734699056447173
#StayGrounded #Flightcirrus #contrails #ClimateChange