What is actually understood by light pollution? If you're asking yourself this question, you've come to the right place! Whether through street lamps, in the home or on neon signs - most people now take the existence of artificial light sources for granted. Electric light ensures that we can see in the dark. We also feel safer when we are out and about at night.
However, the earth is getting brighter and brighter, so there are fewer and fewer places that are completely dark. Unfortunately, very few people think about the fact that the annual increase in light emissions has serious consequences for us and our environment.
In this article, I would therefore like to explain everything you need to know about light pollution. From the definition, causes and consequences to the solutions. Let's go!
Definition: What is light pollution?
The term light pollution (also called light smog or light contamination) refers to the Brightening the night sky with artificial light sourceswhich results in the absence of complete darkness in the affected regions. The light from electric lighting is scattered into the atmosphere, which has a negative impact on the environment. This is another reason why light emissions are considered to be pollution caused by artificial light.
And what is natural light? This is, for example, the light of the sun and the stars - in other words, all the light that is not produced artificially by us humans.
Statistics: What facts and figures exist on light emissions and light smog?
So we humans generate a kind of "light waste". But how bad is the problem really? To get a better understanding of this, I would first like to give you some scientific facts and figures about light pollution:
- Worldwide increase: The intensity of artificial lighting and the extent of the illuminated area have increased worldwide by around 2 percent per year since 2012.₁
- Increase in Germany: According to estimates, light pollution in Germany is increasing by around six percent every year.₂
- Intensity: Our cities are sometimes 4,000 times brighter than natural night light due to light emissions.₃
- Insect mortality: In one night, an average of 150 insects die from a single street lamp.₃ According to the Federal Ministry for Economic Affairs and Climate Protection, there are around ten million street lamps on roads, paths and squares in Germany.₄
- Dissemination: More than 80 percent of the world's population and more than 99 percent of the US and European population live under a light-polluted sky.₅
Causes: How does light pollution occur?
Human influence is therefore not only making the earth warmer (keyword climate change), but also even brighter. But how exactly do we cause light emissions? The answer to this question could be an endless list of light sources - I would like to spare you that. Instead, I will present the main causes of the increasing light smog.
Technical progress
The electric Lighting becomes more and more effectiveso that considerably more light can be generated with the same power consumption. The lower power consumption means that even more or even brighter lighting is installed. (Rebound effect)
Poor light distribution
For the most part Light sources not shielded well enoughso that they not only brighten up the object or surroundings to be illuminated, but also shine in all directions in an uncoordinated manner. Even where no light is needed at all.
Eye-catching advertising technology
Advertising has to stand out. That is why more and more digital advertising displays, neon signs, showcases and city light posters the cities. Spectacular spotlights and projections are also used (at festivals, for example).
Expansion of residential areas and infrastructure
In new residential areas, it's not just the houses and apartments that provide a sense of well-being. Streetlights and floodlights for additional light - in places where it was previously quite dark. The expansion of industrial areas also requires corresponding new lighting.
Road traffic
It is not only the streetlights that light up the planet in the dark, but above all the Headlight and lighting of our vehicles.
Decoration
The houses, streets and towns shine particularly brightly at Christmas time, as the Christmas decorations with all the Light curtains, fairy lights and illuminated figures is brought out of the cellar.
Can you think of any other causes of light emissions? Then feel free to write me a comment with your reference.
Consequences: How does light pollution affect us humans and the environment?
Apart from the fact that lighting streets, buildings and advertising displays requires vast amounts of energy, what effect does it have on the environment when the nights are no longer dark? And to what extent are we humans even harming ourselves?
Here I present you now the main consequences of light pollution.
Consequences for animals
In the dark, nocturnal insects orient themselves by the faint light of the stars. However, as the animals are now attracted by the much more intense, artificial light of street lighting or buildings, they leave their usual habitats. They either burn up on the hot lights, wander around them until they are exhausted and are generally concentrated, as if on a silver platter, easy prey for insect predators. This is another reason why light pollution is considered one of the main causes of insect mortality.
Ships, bridges and jetties are also often heavily illuminated, which also affects the underwater world. For example Fishsuch as salmon and eels, are disturbed by the light sources during their spawning migrations. The light from the harbor cities also irritates Sea turtles.
Also Migratory birds are disturbed by the artificial lighting at night, causing them to fly other routes and lose unnecessary energy. Last but not least, the light even has an impact on the mating behavior of many animal species.
Consequences for plants
The chronobiological rhythm of plants is also affected by increasing light emissions. Your natural growth cycle is disruptedso that they are more susceptible to weather damage, for example. This in turn has further negative consequences for wildlife.
Consequences for us humans
Our day-night rhythm is disrupted by artificial light. As a result, we find it much harder to fall asleep, for example. Normally our body releases the sleep hormone melatonin in the dark - However, the brighter it is, the less we can produce and the worse our sleep is.
Our internal clock no longer works as usual. This has health consequences, because it affects our well-being, our relaxation and our ability to concentrate.
Tip: To Sleep betteryou should sleep in complete darkness and, if possible, not sit in front of a flickering television in a fully lit apartment during the time before that.
Have you ever asked yourself why you hardly see any stars at night in the big city? Above cities such as Cologne, Berlin, Munich or Hamburg, there is a large artificial dome of light in the natural darkness. This light pollution ensures that only a small fraction of the approximately 3,000 - 4,000 stars that are visible in complete darkness are visible.₆ This probably has no health effects, but it is also a consequence of excessive human light emissions.
Solutions: What can each of us do to combat light pollution?
Basically, you can stop air pollution by switching off artificial light. Relatively logical, isn't it? However, we humans cannot simply live in complete darkness from one day to the next. Nevertheless, there are a few tips that anyone can implement to significantly reduce their own light emissions:
- Switch off: Actively switch off light sources when you don't really need them. In this way, you can also save costs for Save energy.
- Automatic light: Use timers and motion detectors to ensure that lamps and lights are switched off automatically when nobody needs them.
- Alignment downwards: Position lighting as low and downwards as possible so that it only illuminates the areas where light is required. Upwards lighting is rarely necessary. Above all, try not to illuminate trees and bushes.
- Insect-friendly illuminants: Make sure that the blue components in the light are negligible or non-existent.
- Lamp housing: Make sure that lights in the garden or on the house are surrounded by an enclosure and cannot get hotter than 60 degrees.
- Promote star sanctuaries: In selected places there is no light at all. The Eifel National Park, for example, is a star sanctuary. Support this and the creation of other such star parks.
- Report light sources: Streetlights are often not covered at the top or are generally far too bright. Report such observations to the public utility company in your region to initiate a possible improvement.
- Earth Night: Take part in the annual environmental protection campaign in September, when all the lights in your own four walls are switched off from 10 p.m. at the latest.
Light pollution - a man-made problem for humans and the environment
Fortunately, in everyday or public discussions, people now very often talk about the Environmental problems of our time. However, light pollution is still rarely one of them. It is important that this changes and that we take the problem seriously. After all, bright light in the dark has serious consequences for wildlife, plants and, above all, for ourselves.
Let's learn to live with as little electric light as necessary - and if possible get up with the sunrise and go to bed with the sunset. This is by far the best way to combat light emissions.
I hope that this article has enlightened you. Do you have any questions, suggestions or your own experiences with light pollution that you would like to share? Then I look forward to your comment.
Stay sustainable,
PS.: A somewhat better known environmental problem is the air pollution. I have also put together a detailed blog article about this with causes, consequences and solutions. Have fun!
References:
₁ Kyba, C. C. M., Kuester, T., Sánchez de Miguel, A., Baugh, K., Jechow, A., Hölker, F., Bennie, J., Elvidge, C. D., Gaston, K. J. Guanter, L. (2017): Artificially lit surface of Earth at night increasing in radiance and extent, available at https://www.science.org/doi/10.1126/sciadv.1701528. [06.10.2022].
₂ Bund für Umwelt und Naturschutz Deutschland (BUND): Light pollution, available at https://www.bund-sh.de/stadtnatur/lichtverschmutzung. [06.10.2022].
₃ Bayerischer Rundfunk: Earth Night, available at https://www.ardalpha.de/wissen/umwelt/nachhaltigkeit/lichtverschmutzung-lichtsmog-nacht-himmel-licht-sterne-tiere-insekten-100.html. [06.10.2022].
₄ Federal Ministry for Economic Affairs and Climate Protection: Let there be light - with energy-saving street lamps, available at https://www.bmwk.de/Redaktion/DE/Artikel/Hightechlight/energiesparende-hybridleuchten-fuer-den-aussenbereich.html. [06.10.2022].
₅ Fabio Falchi et al (2016): The new world atlas of artificial night sky brightness, available at https://www.science.org/doi/10.1126/sciadv.1600377. [06.10.2022].
₆ Quarks: Light pollution: That's why you can hardly see any stars in cities, YouTube, 28.02.2019, Web, 06.10.2022 at 11:02, in: https://www.youtube.com/watch?v=cKOi6YGRuWU.
