Step outside on a clear night almost anywhere in Britain and look up. For roughly a third of the global population, the Milky Way is simply gone, permanently bleached out by the orange glow of our own making. But light pollution is no longer just an astronomer’s complaint, it has become a public health crisis, an ecological emergency, and a regulatory blind spot all at once.
The Royal Astronomical Society has had enough and, following a major conference on light pollution held earlier this year, the RAS is now calling for artificial light at night to be legally recognised as a pollutant placing it alongside air, water, and plastic in the hierarchy of environmental threats requiring urgent legislation.
World map of light pollution. False colours show intensities of skyglow from artificial light sources around the world (Credit : David Lorenz)
The case for doing so is compelling. Exposure to artificial light at night is linked to a catalogue of serious health conditions: type 2 diabetes, obesity, dementia, Parkinson’s disease, and retinal damage. Beyond the physical, it disrupts mood and increases rates of depression and anxiety. The mechanism is largely circadian, our bodies are wired to respond to darkness as a cue for rest and repair. Flood the night with light, and that ancient rhythm breaks down.
Wildlife is faring no better with even the lowly caterpillar populations declining by 52 per cent in areas exposed to street lighting. Around one third of insects drawn to artificial light sources die from exhaustion, predation, or disorientation. Plant pollinator interactions fall by up to 62 per cent under artificial light, quietly undermining the reproductive cycles of plants we depend on. In Europe, half of all known firefly and glow worm species are now threatened with extinction. In the oceans, 22 per cent of the world’s coastlines are bathed in artificial light disrupting coral spawning, confusing sea turtle hatchlings and suppressing the vast daily migrations of zooplankton that underpin marine food chains. The cumulative picture is stark since of all species that list light pollution as a recognised threat on the International Union for Conservation of Nature ‘Red List,’ 45 per cent are classified as at risk of extinction.
A female glow worm (Credit : Nevit Dilmen)
Other countries are already acting. Croatia has adopted comprehensive national legislation on light pollution, dividing the country into lighting zones with specific restrictions. Germany has banned new street lighting in nature reserves. France has embedded light pollution targets into its National Biodiversity Strategy, aiming to halve lighting emissions by 2030. Britain, by contrast, still operates under a 1990 law that explicitly excludes light as a pollutant, and a 2005 Act that treats it as nothing more than a neighbourhood nuisance.
The RAS is pushing for that to change. Working alongside the All Party Parliamentary Group for Dark Skies, the Society wants light pollution addressed within the framework of the Environment Act 2021, legislation that already sets binding targets on species decline and environmental governance. The window exists but so far, the political will does not.
In the meantime, the fixes are not complicated. Use warmer toned LED lighting rather than bright white. Direct light downward, not outward. Switch it off when it isn’t needed. Simple measures, but ones that could give back something we’ve quietly surrendered, the night itself.
Source : Artificial light a ‘pollutant’ to humans, nature and astronomy