Light Pollution’s Environmental Consequences and Health Risks

by | Nov 18, 2022 | Environment, Environmental Impact Assessment, Pollution

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What Is Light Pollution?

Most human inventions have caused many types of pollution on Earth. As examples, let’s look at automobiles and a miraculous human invention, plastic. Today, emissions from automobiles are a significant source of air pollution. Plastic is choking our oceans and destroying marine life.

The electric light bulb is one of the greatest inventions of our time. Electric light can be a wonderful thing. It shows us the way home when the sun goes down and keeps our homes bright and cozy, dispelling darkness. Light makes us feel safe. However, like automobiles and plastic, using too much of a good thing can negatively impact the environment.

Light pollution is the excessive and inappropriate use of outdoor artificial light. Light pollution affects human and wildlife behavior. It also interferes with our ability to observe celestial objects like stars.

Light pollution is a global problem. In 2016, as in every year since 2012, the World Atlas of Night Sky Brightness published a computer-generated map of thousands of satellite photos. This was the map that woke up the world to the problem of light pollution. The atlas shows where and how the Earth gets lit up at night. This particular atlas showed vast regions of North America, Europe, the Middle East, and Asia glowing with light. Only the most remote regions of the Earth, such as the Sahara, the Amazon, and Siberia, remained in total darkness. Some countries with the most light pollution include Singapore, Qatar, and Kuwait.

Scientists commonly refer to sky glow as the brightening of the night sky. It mostly happens in urban areas due to street lamps, car lights, factories, offices, billboard advertisements, and buildings.

If you live in a city with high levels of sky glow, you must have had difficulty seeing more than a handful of stars in the night sky. Light pollution is a particular challenge to astronomers. It greatly hampers their ability to view celestial objects.

According to National Geographic, 80% of the world’s population lives with light pollution.

Light Pollution’s Environmental Consequences and Health Risks


Effect on Humans

Light pollution wreaks havoc on the natural body rhythms of humans and animals. Circadian rhythm is an internal body clock that guides daily and night activities in nearly all living organisms. Light pollution interferes and confuses a body’s circadian rhythm. A circadian rhythm is responsible for the production of the hormone melatonin. Our body releases melatonin when it is dark and inhibits its release in the presence of light. Light pollution lowers melatonin production at night. This can cause sleep deprivation, stress, headaches, anxiety, and other health problems.

A few recent studies have related reduced melatonin levels to cancer. New scientific findings of the health effects of light pollution have convinced medical associations to support efforts to control our exposure to light at night.

Scientists have found that blue light notably reduces levels of melatonin in humans. Our cell phones, computer devices, and most light-emitting diodes (LEDs) emit blue light.

Effect on Animals

Light pollution is a major threat to nocturnal wildlife. It has a negative impact on plant and animal physiology. It also affects animal behavior, such as habitat formation, wake-sleep habits, and migration patterns. Sea turtles and birds use the moonlight as a way to navigate at night. Because of light pollution, they often get confused during migration, lose their way, and die.

Insects are a food source for birds. Bright artificial lights at night attract insects. These insects almost instantly die upon contact with the light source. This affects birds. Because of all these inconveniences to wildlife, many cities around the world have now adopted a “Light Out” program. They turn off building lights during bird migrations.

Scientists studying blackbirds in Germany found that birds in the city become active sooner in the day than birds in natural areas. The city’s traffic lights and artificial night lighting cause them to wake up as much as five hours earlier than their cousins in the countryside.

One study investigated the impact on marine animals by artificial underwater lighting. The study group submerged brightly lit panels underwater off the coast of Wales. They recorded that very few filter-feeding animals made their homes near the lit panels. The study showed that underwater light from passing ships, harbors, and oil rigs alters marine ecosystems.

What Can You Do To Combat Light Pollution?

There are chiefly three types of light pollution:

1. Glare

Glare is intense, excessive brightness that causes discomfort. For example, the glaring lights from passing vehicles while you drive.

2. Clutter

Clutter is the excessive, confusing, and bright groupings of light sources. You must have seen a picture of Times Square, New York, at night. What you’re looking at is an ideal example of clutter.

3. Light Trespass

Light trespass refers to the extension of light into an area no one wants or needs light in. For example, light from a streetlamp illuminated a nearby bedroom window.

Light Pollution’s Environmental Consequences and Health Risks

About 100 years ago, you could go out on the streets at night, even in cities, and look up at our galaxy, the Milky Way, stretching across the night sky. Light pollution is causing us to lose touch with our cultural heritage. The night sky completely lit up with millions of stars is what inspired artists like Van Gogh and writers like Shakespeare. 3 out of every 4 people living in cities have never experienced a pristinely dark sky. You shouldn’t need sunglasses at night.

If you want to help fight light pollution, use light only when and where you need it. Also, make sure that the streetlamps around your house direct light down instead of up into the sky. Close your window blinds, curtains, and shades at night to keep the light inside your home from extending outdoors. This way, you can protect the little wildlife around you. You can also use highly-efficient light sources in your home that save energy and reduce light pollution. Lastly, increase public awareness. Talk to your friends and family about the importance of what we, as humans, have lost to light pollution.

Light pollution is a primary concern on many fronts: energy conservation, safety, cost, and effects on humans and the environment. Taking even small steps to fix this problem is worthwhile.




  • Dr. Emily Greenfield

    Dr. Emily Greenfield is a highly accomplished environmentalist with over 30 years of experience in writing, reviewing, and publishing content on various environmental topics. Hailing from the United States, she has dedicated her career to raising awareness about environmental issues and promoting sustainable practices.

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