The Royal Astronomical Society (RAS) of the United Kingdom is calling for urgent action to address the damage that light pollution causes to human health, astronomy, biodiversity, and the natural environment.
Light Pollution and Disease
According to the RAS, inadequate exposure to natural sunlight combined with excessive exposure to artificial light at night can disrupt metabolism and contribute to the development of conditions including type 2 diabetes, obesity, dementia, Parkinson’s disease, and retinal disorders. There is also evidence suggesting it directly affects mood and increases the likelihood of depression and anxiety.
The Impact on Nature
The harm caused by light pollution extends well beyond human health. Artificial light significantly affects the natural environment, accelerating the loss of biodiversity, particularly among nocturnal species that depend on natural darkness to survive, and fragmenting ecosystems. Marine biodiversity has also been affected. According to available data, one third of insects attracted to artificial light sources die as a result of exhaustion, disorientation, or predation. Light pollution also reduces plant-pollinator interactions by up to 62%, with significant consequences for plant reproduction.
Astronomy at Risk
Artificial light and light pollution can also threaten the visibility of the night sky, both for professional astronomers and for the general public. The RAS stresses that reducing light pollution is essential for the protection of astronomy as a scientific discipline.
A Call for Legal Recognition
Given the scope of these harms, the RAS is calling for artificial light at night to be formally recognized in law as a pollutant. The organization also emphasizes that night should be recognized as an integral part of the natural environment, deserving of protections equal to those afforded to daytime activities, in order to strengthen conservation efforts.
Five Principles for Responsible Outdoor Lighting
The RAS recommends tackling light pollution through five principles of responsible outdoor lighting:
- using light only when there is a clear purpose
- directing light only where it is needed
- reducing light intensity
- using light only when necessary
- choosing warmer-colored lighting.
Members of the public can also contribute by switching off lights where and when they are not needed, and by replacing bright white LED lighting with lower-color-temperature alternatives.
