Passion of the people – 1.7.1

What is light pollution?

The bright side of light

Light has fascinated people since time immemorial. Light has an emotional, aesthetic and soothing effect on us. Once our ancestors discovered the power of fire, they felt power over darkness. Yet for many thousands of years to come, they had to make do with light from the sun, moon, stars and fire. In the 19^th century, inventors developed different kinds of light bulbs until Thomas Edison refined and patented an incandescent bulb in 1879. A game changer! The invention of electric light boosted humanity’s power over the night. People started to illuminate the Earth more and more; the planet has become ever brighter. Light no longer only serves people’s needs for safety and security. We use it for advertising and festive purposes, for traffic, industrial, and leisure sites. In many places, we can no longer see the starry sky.

What is light pollution?

Light pollution means too much light in the wrong place at the wrong time. It is the superimposition of natural light by artificial light. 99 percent of Europeans, North Americans and Japanese live under light-polluted skies! Light bells of large cities can be seen on the horizon hundreds of kilometres away. The main sources are lights from private companies, e.g. shops and façades, whereas public sources such as street lighting account for a smaller part. Only recently have we begun to fully discover and understand the negative impacts that our illuminated nights have on human health and on ecosystems.

Night on Earth?—Prime Time for animals and plants

Two out of three animal species on the planet are nocturnal. They rely on darkness and natural light from the moon and stars to orient themselves, move, reproduce, hunt or forage. Artificial light affects vital life functions, processes, and behaviour of animals. This can lead to the extinction of species. Light pollution amplifies biodiversity loss.

Bright homes—a danger to human health

Many of us spend many hours of our lives under artificial light. This distorts the production and balance of melatonin, known as “sleep hormone”, and thus our sleep-wake rhythm. Excessive use of artificial light in the evening and night hours can threaten our health. The most problematic light is blue light emitted by screens.

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Passion of the people

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*Light pollution on Tenerife. Image by Cestomano – flickr*

*Light polluted landscape. Image by pixphil22 – Pixabay*

Further resources

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Images

Satellite images of Earth at night – NASA Earth Observatory images (NASA)