So you remember the water cycle? You probably learned about it at school. Maybe you made a clever little water cycle model with cotton wool. But what does that have to with the essential oils in your favourite products - you certainly didn’t include those in your papier-mâché creation..
But, if you look a little closer, you’ll realise that you did. By including trees or the rainforest, you inadvertently included the chemicals those plants release. And those chemicals, well, they’re the exact same ones that you’ll find in a bottle of essential oil.
Plants produce chemical compounds to help them stay alive. These chemicals can attract pollinators, repel predators and provide protection from harm. Some of them can even help create clouds when rainwater or shade is needed. Yup, those chemical compounds that make you feel zenned out in the bath, well they help plants from burning up in the rainforest sun too.
Dr Stephan Harding is an ecologist, senior lecturer and coordinator of the MSc in Holistic Science at Schumacher College - an institution with an international reputation for nature-based education surrounding ecology and sustainability. He explains: “Secondary compounds that plants make can smell nice. People like to put them in soaps, shampoos and lots of things. Well, trees and plants make those compounds for a reason.
“One of the reasons, and there are several, seems to be to control climate. Trees release them and they waft up into the atmosphere above the forest and help to condense clouds - to seed clouds.”
Clouds are formed when tiny drops of water or ice settle on dust particles in the atmosphere. But it’s not just dust that clouds can form around - you’ve guessed it - it’s essential oil compounds too. The chemical particles, most commonly a type called terpenes, are released into the air by plants, and clouds are then able to form around them.
Stephan says: “The water molecules cluster around these aromatic compounds, and the water vapour condenses into clouds. Eventually water falls back in the forest. This is the way the forest keeps the water cycling.
“But the clouds themselves are dense and white too, so they also cool the earth. They have an impact on the entire climate. There’s a link between these little tiny compounds, and climate regulation in the biosphere. This is a real phenomenon.”
So, can your bath bomb make it rain? Probably not. Although the chemicals contained in essential oils, like geraniol, farnesol, and linalool, are terpenes and can be used by plants to create clouds, the amounts that are released into the air from products is minimal. Stephan says: “I imagine a small amount will waft away, escape through windows and get into the air and help seed cloud but it would be a very very small amount.”
There you have it. Essential oils are more than just smellies that make you look and feel great, they have a whole host of other roles in nature and beyond. Read more here.
Dr Stephan Harding is author of Animate Earth, Science Intuition and Gaia , where you can learn more about cloud seeding. He is also co-author of the deep time walk app.