Myth debunked: Contrails vs chemtrails
Contrails are formed when water vapour condenses around dust particles emitted by an aircraft’s engines
Have you ever wondered what those line-shaped formations in the sky – that can persist from a few minutes to several hours – are?
A popular conspiracy theory is that these are ‘chemical trails’, or ‘chemtrails’, and are part of secret government programmes intended to dump chemicals into the atmosphere for such purposes as human population control, weather modification and chemical warfare.
In reality, these formations are ‘condensation trails’, or ‘contrails’, that form when water vapour condenses around dust particles emitted by an aircraft’s engines, typically at cruise altitudes.
Water vapour is naturally present in the atmosphere and in engine exhaust.
For contrails to form, the air needs to be moist and cold; if it is dry, contrails disappear quickly, whereas, if it is humid, they last longer.
A little-known fact is that contrails contribute to climate change – on a level similar to that of aviation’s CO2 emissions – because water vapour has a high heat capacity and, therefore, when it warms up, it traps heat in the atmosphere for longer.
It is interesting to note that a hydrogen-powered aircraft, which has been touted as a possible future solution for cleaner aviation, will emit less CO2 but much more water vapour. This will potentially lead to even more contrails, which may offset the environmental benefits.
