Cloudy with a chance of meatballs: how frying food could be altering the weather

Healthy eaters may have something to feel extra smug about.

Fried fatty food not only has an impact on waistlines, it is also affecting our weather systems, according to scientists.

Chemists at the universities of Reading, Bristol and Bath have discovered that when droplets of cooking fat are released into the atmosphere they form complex structures which attract moisture and form into clouds.

In large cities like London, cooking fat is known to be responsible for 10 per cent of small particles in the air, so researchers believe frying food could have a noticeable impact on cloud formation and rainy weather.

In fact, the effect is so large it could even have a cooling effect on the planet, and potentially slow down global warming.

“I think it could be having an impact on cloud formation,” said Dr Christian Pfrang, Associate Professor of Physical and Atmospheric Chemistry at the University of Reading.

“It is likely that these structures have a significant effect on water uptake of droplets in the atmosphere, increase lifetimes of reactive molecules and generally slow down transport inside these droplets with yet unexplored consequences.

“We’re not saying that becoming a healthier eater could have an impact on climate, but fat does seem to encourage cloud formation.”

In laboratory experiments, researchers levitated droplets of saltwater and oleic acid, a fatty acid associated with cooking.

They found that the molecules in the droplets arranged themselves into crystal-like lattice structures which act like a sponge to trap water. The complex structure also helps the droplets to survive longer in the atmosphere, enhancing their ability to seed clouds.

The researchers have so far only conducted experiments in a lab, but now want to see how the droplets react in the environment.

During cooking, fat droplets end up in the air by floating out through extractor fans or windows. 

Dr Squires, Associate Professor of Biophysics and Materials at the University of Bath, said: “We know that the complex structures we saw are formed by similar fatty acid molecules like soap in water.

“There, they dramatically affect whether the mixture is cloudy or transparent, solid or liquid, and how much it absorbs moisture from the atmosphere in a lab.

“The idea that this may also be happening in the air above our heads is exciting, and raises challenges in understanding what these cooking fats are really doing to the world around us.”

The research was published in the journal Nature Communications.