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Light pollution-extend, social and ecological impacts and approaches for action

Source: Office for technology-assessment (TAB) at the German Bundestag

Type: Report

Author: Christoph Schröter-Schlaack; Christoph Revermann; Nona Schulte-Römer,

Institution: Institute for technology assessment and system analysis (ITAS)

Field of Research: Environmental and health risks: light pollution

Source file: DOI:10.5445/IR/1000121964

Year: 2020

re:look climate text: Nadine Oppenberg and Philipp Lengsfeld

re:look climate teaser:

This outline deals with the report of the Office for Technology Assessment by C. Schröter-Schlaack with the collaboration of C. Revermann and N. Schulte-Römer, which was prepared on behalf of the German Bundestag in 2020 and comprises 196 pages.


Since the establishment of artificial light, there is hardly a place in the world without electrical radiation. On the one hand, new time windows could be used, which were previously unsuitable for working due to the persistent darkness. However, artificial light has the potential to affect the environment and health by interfering with the day/night rhythm. The risk potential behind artificial light and how this can be counteracted is examined in more detail in this outline.

When considering artificial lighting, a distinction is made between useful light (illuminating the target area), wasted light (illuminating surrounding areas) and disruptive light (unwanted illumination of house facades or the creation of skyglow) (Figure 1). The negative effects of lighting outside the target area range from wasting energy to effects on the day-night rhythm of the residents of surrounding houses and the wildlife with far-reaching consequences.

Fig. 1: Different sides of artificial light (source TAB report)

Health risks

Illumination of the actual dark phases can have an effect on the sleep rhythm in humans. Due to the lack of darkness, there is insufficient tiredness, the sleep phase is pushed back and a lack of sleep can arise, which can lead to an increased risk of accidents and daytime tiredness, for example. Blue light in particular inhibits the release of melatonin. The presence of the hormone is linked to the development of muscle mass, bone mineral density and sleep regulation. Furthermore, melatonin has an anti-cancer effect. Disruptions in the circadian rhythm and lack of sleep can lead to changes in the physiological appearance. As studies in the sleep laboratory have shown, these disorders can be similar to conditions in a diabetic or cardiovascular patient.

Environmental risks

A brightening of the night mainly affects those organisms that have adapted to the darkness. About a third of all vertebrates and even two-thirds of invertebrates are nocturnal and have adapted to the light conditions. As in humans, acute and circadian arrhythmias can also occur in animals. Artificial lighting can also lead to behavioral changes, such as a postponed hunting or resting phase. While certain species avoid places with strong lighting, other species, such as insects, are attracted to brightness. This can result in increased mortality of certain species from predation while also inhibiting the occurrence of certain species in heavily lit areas. This shift in the occurrence of different species can have large-scale impacts on an ecosystem and have far-reaching consequences. However, precise investigations of comprehensive consequences are highly complex and have not yet been sufficiently clarified due to influencing factors such as climate change, urbanization and biocide inputs.


Addressing pollution from artificial light is important given the multiple impacts it has on human health, the environment and animals. Measures to modernize lighting systems throughout Germany are largely aimed at energy efficiency. Part of the consequence of this is that the intensities tend to continue to increase. Measures to contain light could be adapting or completely avoiding outdoor lighting in places that are not absolutely necessary. This can be achieved by banning neon signs from ads or reducing street lighting. Furthermore, the spectral composition of the light can be changed so that short-wave blue tones are avoided.


Artificial light harbors various risks, which are not always immediately apparent at the first view. With current efforts, the disturbing light cannot be contained. In order to significantly minimize the negative effects, there is a clear need for action in this area, which goes far beyond the current efforts.

This teaser can be seen as an introduction to the series "Light pollution - risks and possible courses of action, an overview of the TAB report of the German Bundestag", which is continued with two further parts.

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Source: Office for technology-assessment at the German Bundestag Type: Report Author: Christoph Schröter-Schlaack; Christoph Revermann; Nona Schulte-Römer, Institution: Institute for technology assess


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