home Features, Opinion Light Pollution: Let’s Bring Back the Night

Light Pollution: Let’s Bring Back the Night

Connor Fagans, J. Luna Auerbach, Leo Belman, Clio Halpern, Matthew Lerohl | April 19, 2019

Map of Light Pollution in the U.S. (Atlas 2015)

A bird is completing the final leg of its winter migration. Its species has flown the same route for millenia, and, if it arrives home safely, it will breed and propagate the next generation. Suddenly, an inviting yellow glow appears over the horizon. The bird shifts its course towards the light, until it, and the stars it needs to navigate, are fully enveloped in the blinding glare. Suddenly, it notices a towering skyscraper directly in front of it. Unable to swerve out of the way, the bird slams into the window, and, its wings in tatters, tumbles down to land on the cold concrete 13 stories below.

A few weeks ago, we didn’t know much about light pollution; like much of the d.tech community, we only really knew that light pollution prevents us from seeing the stars. While this is true, we have discovered that the issue is so much more complex. The potential of ALAN (Artificial Light At Night) to lure birds into brightly lit urban areas where they may become disoriented and crash into buildings is just one of many negative impacts associated with light pollution. Researchers at the University of Delaware, who uncovered this correlation using weather radar, are also concerned that birds that stop in these urban areas may not have access to the resources they need to continue their journey.

According to the International Dark-Sky Association (IDA),  light pollution is an unnatural influence that disturbs the natural balance between night and day. The IDA cites a study which found that 99 percent of the American public can no longer experience a natural unlit night. The effects of artificial light on humans aren’t just restricted to being unable to see the stars, though. Humans produce a natural hormone called melatonin that helps us get healthy sleep. According to the IDA, ALAN suppresses the production of this hormone, and, as a result, makes it harder for humans to sleep, which in turn disrupts our circadian rhythm. A lack of good sleep can lead to simple, immediate effects, such as irritability, mild or short-term depression, and lack of focus. Artificial light also has the potential to lead to long term serious effects, such as obesity, diabetes, and heart disease.

Spanish Teacher Carolina Moroder felt compelled to spread the word about light pollution when she created her own d.lab focused on the issue, “What Did We Do to the Night?” Moroder first learned of the issue while studying culture surrounding the moon to develop a lesson around teaching her Spanish 4 students a song known as “Hijo De La Luna”. This project, however, quickly ballooned into a much larger study of the relationship between humans and the night. The issue “exploded in front of me,” says Moroder. Once she had learned about the night’s importance in our lives, it became a passion of hers to do what she could to preserve it. When the opportunity presented itself for her to educate the next generation on this issue through her d.lab class, she seized it, because “you students need to realize – we are all stewards of the world.”

We also spoke to some students about light pollution, and found that many were uninformed, with even those who knew more not finding it to be a pressing issue. “Light pollution is an issue, but there are more important ones to think about, such as global warming,” said junior Zach Nemirovsky.  He also noted that artificial light can be useful even when it seems to be wasted, saying, “When we go on vacation, my family leaves one light on in the house, 24/7, so we are not robbed.”

However, according to numerous studies, leaving your lights on at night does not prevent crime. In fact, excessively bright lights have been found to increase crime in some cases. A 2015 study published in the Journal of Epidemiology and Community Health [1] examined possible ways to reduce energy consumption of street lighting, and found that dimming, or even completely switching off, outdoor lights didn’t cause any increase in crime whatsoever. Researchers examined police data on traffic collisions and crime from 62 local authorities and found no associations between light levels, traffic collisions, or crimes. Another study evaluating the impacts of the Chicago Alley Lighting Project [2], examined the impact on crime when the light level in Chicago alleyways was increased. Researchers from the Illinois Criminal Justice Information Authority studied crime in an experimental area prior to and after increased alley lighting was installed. These results were also compared to a control area with similar demographics. The researchers observed a 21 percent increase in total crime when alley lights were replaced with higher power fixtures. Bright lighting can also create glare that blinds cameras and makes it harder for the eyes to focus on darker parts of the street where criminals may be hiding.

This study showed an increase in crime when alley lights were replaced by higher power fictures (Red is lower brightness fixtures, Blue is higher brightness fixtures).

Though many students see light pollution as a trivial issue, big change needs to start somewhere,  and this may be the easiest type of pollution to fix. We must all contribute, even in small ways, to see real change. There are many ways you can help; it can be as simple as turning off unused lights around your home at night, or as proactive as speaking with local officials to tackle light pollution citywide. Another way you can help is by replacing poorly designed lighting fixtures that send light upward with well designed fixtures certified by the IDA. These fixtures are engineered to only direct light downwards, reducing light pollution and increasing efficiency, saving you money in the long run. You can learn more about such fixtures and other ways you can help at darksky.org. Let’s bring back the birds, the sleep, the natural way of life and the beauty of our night sky.


[1] Steinbach R, Perkins C, Tompson L, et al The effect of reduced street lighting on road casualties and crime in England and Wales: controlled interrupted time series analysis J Epidemiol Community Health 2015;69:1118-1124.

[2]  Morrow E, Hutton S, Research and Analysis Unit, Illinois Criminal Justice Information Authority, “The Chicago Alley Lighting Project: Final Evaluation Report”

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