Royal Astronomical Society Urges Governments to Classify Artificial Light as Pollution

U.K. Royal Astronomical Society is urging governments to formally recognize artificial light at night as a pollutant. The organization cited evidence that rising light levels affect human health, biodiversity, and astronomical observations. A 2023 paper reported that the night sky grew about 10 percent brighter per year between 2011 and 2022, based on citizen-science data.

One location that showed 250 visible stars in 2011 displayed only 100 stars by 2022.

Researchers presented data linking nighttime light exposure to higher rates of type 2 diabetes, obesity, Alzheimer’s disease, Parkinson’s disease, and retinal damage. Additional findings connected the exposure to increased depression and anxiety. Marieta Valdivia Lefort, Policy & Diversity Officer at the RAS, said there is increasing scientific evidence that artificial light is having a significant and lasting impact on the natural environment and human health.

Conference presentations also showed that moth caterpillar populations declined 52 percent in areas with street lighting. Researchers estimated that one-third of insects drawn to artificial lights die by morning, and nocturnal plant-pollinator interactions fell by 62 percent.

The RAS recommends that governments adopt five principles for outdoor lighting: use light only for a clear purpose, direct it only where needed, reduce unnecessary brightness, limit duration, and choose warmer-colored lighting. K. Environment Act 2021.