It is an alarming fact, but for years, stars are less and less visible to the naked eye, and some regions never see the stars at night. But beyond this aspect, light pollution is a major environmental problem and increasingly worrying, since it now concerns almost the entire planet.
Light pollution is the excessive use of night light from multiple sources, such as public lighting, businesses, shopping malls, advertisements and homes, which leads to adverse effects on the environment. Although artificial lighting has become essential for the safety and comfort of our cities, too much light can cause serious problems for the environment, especially for ecosystems.
Artificial lighting can disrupt the migration and reproduction rhythms of animals by disrupting the day-night alternation essential to life. Similarly, night lighting disrupts the natural system of prey and predators. These artificial lights can become death traps for these species. Some migratory birds that travel at night may become disoriented as they approach cities and die from collisions or exhaustion while circling these lighted areas.
For example, nocturnal insects and birds are species that use light sources to navigate at night. However, street lights have gradually replaced the moon and stars, drawing these animals into hostile environments. For example, nocturnal insects are also attracted by light. In particular it has been observed a disruption of the nocturnal pollination of plants by moths.
In addition to the effects on ecosystems, light pollution also has a negative impact on humans. Thus, artificial light alters our cycle and can cause sleep problems and even long-term mood disorders. Night light also tends to disrupt the production of melatonin, which is a hormone we produce that is essential to regulate sleep and wake cycles and gives temporary cues to our body.
Also, night lighting is often useless at night and leads to an increase in electricity costs and a considerable waste of energy.
Various solutions are proposed today to mitigate the negative effects of light pollution. One of them is to use less energy consuming lighting systems, such as LED lamps, which are more efficient and energy saving than the old lighting systems. However, the advent of LED lighting has unfortunately had an incentive effect due to its affordability, making it accessible to more people and thus increasing the number of lights.
In additional, lighting can be banned after a certain time, and new streetlights should be equipped with shades to direct light primarily to the ground and have motion sensors to limit permanent lighting. Some sparsely populated municipalities have already banned lighting in public buildings from 11 p.m. to 6 a.m.
Sources :
https://cbiodiv.org/accueillir-la-biodiversite/la-pollution-lumineuse
https://www.ecologie.gouv.fr/pollution-lumineuse
https://www.actu-environnement.com/ae/news/france-pollution-lumineuse-hausse-41058.php4
https://www.vie-publique.fr/en-bref/288093-pollution-lumineuse-un-phenomene-massif-en-zones-urbaines
