Irresponsible use of artificial light at night (ALAN) results in glare, sky glow, and light trespass, all of which robs us of the ability to view the wonders of the night sky. A growing body of evidence links the brightening night sky directly to measurable negative and deadly impacts on a wide range of creatures in the natural world. The Sonoran Desert, one of the world’s most biodiverse deserts, hosts numerous species whose survival depends on natural darkness. ALAN affects not only nocturnal creatures but also diurnal species, active during the day, and crepuscular species, awake at dawn and dusk. Introduction of light at night in otherwise dark nighttime habitats triggers unnatural periods of attraction or repulsion that disrupts mating behavior and reproduction, interrupts feeding patterns, and alters the food chain.
Recent research findings also point to serious effects on human health.
- Sleep disruption: Exposure to light at night suppresses melatonin production, leading to sleep disorders, insomnia, poor sleep quality and depression
- Increased disease risk: Studies link nighttime light exposure to higher rates of obesity, diabetes, stroke, and certain cancers
- Circadian rhythm disruption: Our bodies evolved with natural day-night cycles; constant light exposure confuses our internal clocks, affecting everything from hormone production to immune function
- Mental health: Loss of connection to natural night skies contributes to anxiety and disconnection from nature
Plants and insects are also adversely affected by ALAN. Trees and crops can be “tricked” by light at night by not performing their normal, seasonal transformations which adversely affects plant health and reduces crop yields. ALAN has also been found to be a major factor in the decrease in insect populations, particularly the night pollinators. Our media is calling attention to an “apocalypse of the insects” and how such a drastic decrease in pollinators can affect world food production and sustainability.
The Good News: Light Pollution is Reversible
Here is what makes light pollution different from other environmental challenges: it is the most straightforward form of pollution to control. Unlike air or water pollution, which can take decades to clean up and require complex chemical processes:
- Turn off a light, and the pollution disappears instantly
- No expensive cleanup or remediation required
- Benefits appear immediately, not after years of effort
- Simple, cost-effective solutions, like shielding, dimming, and better timing
- Often saves money through reduced energy costs
This makes light pollution one of the most solvable environmental problems we face. Every properly shielded light fixture, every unnecessary light turned off, and every community that adopts smart lighting policies creates immediate benefits for wildlife, human health, and energy conservation.
How You Can Help
There are lots of ways to combat light pollution and help protect the night sky. Here are just a few:
Attend, participate or sponsor a DarkSky outreach event. Learn how improper outdoor lighting can harm human health, wildlife and migrating birds and insects.
Engage with your neighbor, neighborhood or HOA to “spread the word” on the adverse effects of light pollution and its effects on the environment (almost all living things, to include we humans) and the enjoyment of an awesome night sky.
Join neighbors in a neighborhood “light walk” to identify obtrusive outdoor lighting.
Most importantly, start your campaign at your front door. Being an example of responsible lighting will set the standard for your neighborhood. DarkSky’s Home Outdoor Lighting Assessment provides simple guidance on how to make your home Dark Sky and Natural World friendly.