What combines energy expenditure, deterioration of human health and impacts on biodiversity? Light pollution! This phenomenon refers more precisely to the presence of abnormal light during the night. Like many areas, the Parc de la Montagne de Reims is studying the consequences of photopollution on a local scale. The objective? Guarantee better integration of lighting into the night landscape, for the well-being of all!

The many effects of light pollution

In recent years, the subject of light pollution has gained momentum, as evidenced by the ministerial decree of December 27, 2018 relating to the prevention, reduction and limitation of light pollution. Indeed, its consequences on ecosystems and organisms are multiple and very real.

On the living

The Migrator birds, Bats, nocturnal raptors, invertebrates and l'herpetofauna (reptiles and amphibians) are deeply affected by excessive lighting at night. For what ? Because for millions of years, these species have adapted their senses to their nocturnal environment. Thus, light disorients them, blocks their communications and disrupts their interactions. In short, the light is night!

Do you think this is a minority? Make no mistake: 64% of invertebrates and 28% of vertebrates are active during twilight and/or night…

On human health

Artificial light is also not the best friend of the human day/night cycle (also called the circadian cycle). Quite the contrary! As a diurnal species, we need a dark environment to secrete the valuable sleep hormone (melatonin). However, exposure to blue light (particularly present in screens) inhibits the latter1, and prevents us from properly joining the arms of Morpheus.

Ultimately, the disruption of this day/night cycle disrupts our immune system: light pollution is also declared as endocrine disruptor2. The relative risk of breast cancer also increases significantly when at least 3 nights are worked each month for 20 years.3. Furthermore, in 2007, the International Agency for Research on Cancer (IARC) classified shift and/or night work in group 2A of “ probable carcinogens, because they involve circadian disorganization.” 4

On the economy

The wallets of the French do not escape light pollution unscathed either! According to ADEME, public lighting represents 41% of electricity consumption local authorities and 37% of their electricity bills. However, through its renovation and virtuous practice, it is possible to reduce energy consumption by more than 75%.

Yes, taking action against photopollution allows you to quickly make significant savings! According to the National Association for Night Sky and Environmental Protection, €5 was saved by municipalities awarded the Star Cities and Villages label, thanks to their implementation of nighttime extinction in 2019-2020. €200 was also saved by reducing the lighting power. Finally, on average, 000 kWh were saved per inhabitant in these municipalities.

Received ideas, the main obstacles to the fight against light pollution

Despite all these negative consequences, some actors are reluctant to reduce their lighting. In question ? Prejudices, which make them fear (wrongly) the increase in the following facts.


However, the figures from the Ministry of the Interior are clear: 80% of burglaries take place during the day, whether in the middle of the morning (25% between 8 a.m. and 11 a.m.) or in the afternoon (55% between 14 p.m. and 17 p.m.)!

Conversely, nighttime lighting can even encourage theft. In 2016, the town of Rochefort (Charente-Maritime) experimented with an extinction measure for 6 months. Result ? “We observed, with the police station, in the three test neighborhoods, a drop in burglaries of 20%” 5.

Incivility and offenses

There has never been any research to assess the impact of public lighting on safety, according to the Center for Studies and Experience in Risks, Environment, Mobility and Urban Planning (Cerema) 5.

However, " the municipalities which have set up experiments ensure that nighttime extinction has not led to more crimes », Says Anne-Marie Ducroux, president of the National Association for the Protection of the Night Sky and Environment, which issues the “Starry Cities and Villages” label.

Road accidents

A study analyzed fatal accidents on Belgian motorways in 2014-20156. She indicates that only 16,5% of them took place in complete darkness. Other factors must in fact be taken into account, in addition to the simple absence of lighting (excessive speed, alcohol, fatigue, etc.).

The (luminous!) accompaniment of the Park

The Park is present on a daily basis to raise awareness and help the municipalities in its territory in their relationship to night lighting.

Thibaud Rault, Ecological and energy transition project manager

This first happens through interventions with adapted tools among residents or during municipal council meetings, public lighting compliance meetings, etc. Of the night entertainment organized by the Park, in partnership with the Reims planetarium, also allow local populations to reclaim the night.

Finally, the Park carries out light pollution and dark frame studies. These are valuable for raising awareness of the problem in the region, and creating effective awareness-raising materials.

Need more lighting?

To go further, don’t hesitate to come to the Maison du Parc! You can obtain a copy of our practical guide “Better living at night: fight against light pollution”.

Another option to shed light on this subject: read the dedicated article on the Park Charter revision blog. Of course, an agent at the Park is also available to answer all your questions!


1 Lewy AJ et al., 1980
2 Study by Dufier J.-L. and Touitou Y., 2021
3 Study by Schernhammer ES et al., 2001
4 Straif K et al. 2007
5 The gazette of the communes, 2018
6 Slootmans F. and Daniels S., 2017

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