As Night Became Day: Light Pollution, An Underappreciated Environmental and Human Stressor

Artificial light at night has fundamentally altered the way we interact with the environment. In a little more than a century, our use of nighttime lighting evolved from an opportunity into an imposition. Light pollution remains an underrecognized harm, although knowledge of its impacts is growing as research increases. Excessive light at night disrupts the natural patterns of wildlife, negatively affects human health, and contributes to carbon emissions among other negative outcomes. It has direct implications for numerous United Nations Sustainable Development Goals. Yet, addressing light pollution is a challenge that differs from other pollutants. Light at night is commonly only seen as a benefit without recognizing its negative effects. It is perceived as ethereal, without harm. Paradoxically, unlike most other pollutants, light is more costly to maintain than to reduce. Failure to address light pollution is often due to social, cultural and behavioral choices.