Aeroplane contrails
Aeroplane condensation trails have again become a target for conspiracy theories. Image by EPA PHOTO

Sydney roll clouds were not ‘chemtrails’

James McManagan June 7, 2024

Tubular clouds seen over NSW were dangerous ‘chemtrails’ released from an aircraft.


False. The clouds were a rare naturally occurring weather phenomenon.

AAP FACTCHECK – Unusual tubular clouds stretching across Sydney skies earlier this week were human-made “chemtrails” designed to poison humans or change the weather, according to some social media users.

This is false. Experts told AAP FactCheck they were not created by humans, but were naturally forming altocumulus volutus, or roll clouds, that contained water droplets.

A Facebook post shared images of the unique clouds that appeared over the city on June 4, 2024, claiming they were human-made and harmful.

“Severe chemtrails appearing across Central Coast and Hunter Valley areas today. These are some of the worst ever,” the caption says.

An Instagram post showing footage of the rare clouds includes the caption: “Mainstream media showing what clearly appears to be ‘chemtrails’.”

Professor Todd Lane, an atmospheric scientist at the University of Melbourne, says the roll clouds formed naturally and were made up of small water droplets.

“I am confident that these would not have been caused by a passing aircraft,” he told AAP FactCheck.

One of the Facebook posts spreading the false claim
 Facebook posts are amplifying false “chemtrail” claims. 

The Bureau of Meteorology explains that the roll clouds likely formed by two unique weather events: an “upper-level temperature inversion” and “wind speed shear”.

Temperature inversion is when a layer of warm air in the atmosphere sits over a layer of colder air closer to the ground, while wind shear is a change in wind speed or direction. 

“This tends to push the top of the cloud forwards faster than the bottom, giving the rolling appearance,” the bureau said in a Facebook post.

Conspiracy theories about chemtrails, a word combining ‘chemicals’ and ‘contrails’ from aircraft, have existed since the 1990s.

AAP FactCheck has previously debunked claims that the long white clouds seen behind planes are ‘chemtrails‘, and that Australia had approved a company to vaccinate people via chemtrails.

The Verdict

The claim that tubular clouds seen over NSW were dangerous ‘chemtrails’ released from an aircraft is false.

Experts told AAP FactCheck that the clouds did not come from an aircraft but were naturally formed of harmless water droplets. 

They have also previously explained that the long white clouds seen behind aircraft are non-hazardous condensation trails.

False – The claim is inaccurate.

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