Light pollution is increasing around the globe, both in its intensity and geographic extent. Researchers are documenting its impact on ecosystems, human health, and culture, while warning that the wasted light has financial costs, environmental impacts, and is responsible for substantial greenhouse gas emissions. In a special issue of Science, five papers discuss the growing adverse impacts of light pollution, along with the regulatory and technological solutions that could help mitigate its effects.
Artificial light at night has variable and complex impacts on plants, animals, and entire ecosystems, according to a paper by Annika Jägerbrand and Kamiel Spoelstra. They discuss how species respond to light pollution in various ways that often differ from other species, making it difficult to develop ways to mitigate the negative impacts of light across an ecosystem. Increasing light pollution is causing habitat loss, disruption of food webs, and declining insect populations.
In a second paper, Karolina Zielinska-Dabkowska and colleagues discuss how the human body responds to nocturnal light exposure. There are effects on visual, circadian, and neurobehavioral systems, due to exposure to urban streetlights, outdoor sporting arenas, and illuminated advertising. They highlight inequities in the levels of exposure to light pollution experienced by different human populations, and the cultural impacts of losing sight of the night sky.
In a third paper, Antonia Varela Perez discusses how professional and amateur astronomers are affected by light pollution. Rapidly increasing sources of pollution for astronomers include large constellations of satellites in orbit, radio-frequency interference, and the deployment of LED lighting that produces more blue light than earlier technologies. Varela Perez argues that locally designated dark sky areas provide benefits for tourism, but there is an urgent need for broader international regulations.
Miroslav Kocifaj and colleagues write in a fourth paper that researchers need better ways to measure and monitor artificial light at night to improve our understanding of light pollution’s causes and to develop mitigation strategies. They discuss how light pollution is measured from the ground and from space by remote sensing, using technologies including photometers, drones, and all-sky cameras. They argue that current data collection practices are affected by meteorological conditions, and that more information could be extracted from them if this is taken into account.
In a fifth paper, Martin Morgan-Taylor examines existing light pollution regulations in various jurisdictions and discusses how they can be improved. Morgan-Taylor suggests that better communication of the carbon emissions and economic waste of light pollution, along with an emphasis on safe but not excessive levels of outdoor lighting, could convince the public and commercial users to reduce the light pollution they generate.
Losing the darkness
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