Shedding some "light" onto Light Pollution

The night sky is beautiful, with the moon and the stars in a dark sky; when we look up to it, it is sort of a reminder of how small we are compared to the universe. But the night sky is also in danger. What is it in danger from? Well, let me shed some light or shall I say some “dark” into the subject.

I previously wrote a blog post about water pollution but this time, I wanted to write about another type of pollution that many might not be familiar with…

A city street lamp

A city street lamp

Growing up in New York City, I thought it was really cool to see the stars; a few here and there, it was pretty neat. But my view of the night sky was always blocked by a city street lamp. When I travelled to Cape Cod and lived on a fairly remote island for the summer, I was blown away when I saw the night sky. Wow! So many stars, I thought. There were twice as many if not more stars than what I saw back home; I even saw the Milky Way. When I returned back home,  I missed all those stars; little did I realize that I was suffering from light pollution. 

Photo Credit to Thomas Hawk

Photo Credit to Thomas Hawk

What is light pollution?

What’s wrong with light?! You might ask. True, it helps us see. But when it comes to looking at the night sky, well, light is kind of a nuisance. Artificial light, that is.

Light pollution is excessive, misdirected, or obtrusive artificial light introduced by humans. It’s also defined as the alteration of natural light levels in the outdoor environment.




Check this out. This is a photo taken from space of "Earth at Night". You can see there’s a lot of light out there during the night; so much light that you can even distinguish major cities from space, like New York City, Tokyo, and London.

"Earth at Night." Credit to NASA. For more information,

"Earth at Night." Credit to NASA. For more information,

How is excess light affecting science and ecology?

Light pollution is a major problem for astronomers and their ability to study the sun, moon, stars, planets, and other objects and phenomena in space. Astronomers need darkness to see the night sky and space clearly. Unshielded light sends light in all directions including up into our night sky. Excess light inhibits us from further studying dim faraway objects in space.

Light pollution not only hinders our ability to the study the sky but can also harm wildlife. Not only does excess light affect nocturnal animals, like owls and bats, but it can also negatively affect and disrupt the reproductive activities of other animals.

Migrating birds will fly day and night to get to their appropriate breeding grounds. For example, tiny birds called red knots will migrate from the tip of South America all the way up to northern Canada and the Arctic almost non-stop to breed. Migrating birds rely on environmental cues such as natural sunlight and the horizon to guide them to wherever they need to go. However, often times their migration routes cross through major cities. Birds may become confused by the brightness of city lights and may fly endlessly until they are exhausted.

Check this article about how 10,000 birds were trapped in a large light beam.

Photo credit to Ginny Dixon.

Photo credit to Ginny Dixon.

The most quintessential example of light pollution affecting wildlife is the reproductive activity of sea turtles. Sea turtles need dark beaches for nesting and laying their eggs. Too much light deters adult females; if a female doesn’t find a dark beach, she will have to resort to laying her eggs in a less optimal place or deposit her eggs in the ocean- a slim outlook for a hatchling to survive, let only hatch.  

If a sea turtle hatches, the risks are far from over. Lighting near nesting beaches can cause hatchlings to become disoriented and to wander inland instead of the ocean. They may risk energy exhaustion, dehydration, and predation. If they wander inland where there are a lot of people around, they may risk being eaten by domestic pets, being run over by vehicles, or drown/ poisoned in swimming pools. 

Photo credit to Jodi Helmer. 

Photo credit to Jodi Helmer. 

Human Health.
In addition to harming wildlife, light pollution can be detrimental to our health without us realizing it. Our natural body rhythms are in tune with days and nights; most people are used to sleeping at night when it is dark. However with the overabundance of artificial light of this day and age, and with distractions like televisions, computers, as well as lamps and bright city lights, we are sleeping less. Decreased sleep causes a decrease in melatonin production; melatonin is a hormone that powers our immune systems and metabolism. Low melatonin levels may put us at risk for cancer, type 2 diabetes and heart disease. 

These are some articles that talk about more the dangers of light pollution to human health:

"Missing the Dark" by Ron Chepesiuk.

"Light Pollution: Light at night and breast cancer risk worldwide" by Angela Spivey.

So what can I do? I still need to see!

An environmental group called the International Dark-Sky Association estimates that one-third of all lighting in the U.S. is wasted. With wasted utilities comes wasted money.

Luckily, light pollution is a “temporary” form of pollution because it disappears as soon as the offending light source is switched off and leaves behind no foul substance or filthy residue. BUT when in progress, it can be very harmful and, with continued exposure, it can cause serious effects on the well-being of wildlife and people in the long-term.

So what can you do? 

>Fix light fixtures and adjust position of lighting. Shielded fixtures prevent light from spreading upward, where it isn't needed. If you’re lighting doesn’t have a fixture, point your light downward.

>Only use lighting that is needed and turn off lights in rooms that are not in use. Use motion detector lights; these can be placed on garden paths, near garages, around dark spaces and even in hallways etc

>Be smart, knowledge is power. The more you know about light pollution and its effects, the more we can prevent it. 

Read about how France is turning out its lights to prevent light pollution.