under natural sunlight, starlight, and moonlight, with their associated natural cycles and seasons. All living things have natural biorhythms that work together with these natural sources of light. There weren’t always the artificial sources of light that we now have in the modern world, such as our street lights, lights from vehicles, electronics, billboards, and buildings, and many other sources of artificial human-created lights. While this abundance of artificial light has given us many advantages in our modern world, it is having many negative consequences on ourselves, our environment, and on all other living things.
In fact, the increasing levels of artificial light in our world are leading to a problem known as light pollution, and it is literally blocking out the night sky that our ancestors knew intimately and ran their lives by for thousands of years. Today, light pollution is increasingly difficult to avoid in our developing world.
Some problems with light pollution
- Light pollution negatively impacts human health
Light induces certain biological conditions in our bodies, making our bodies and our bodily processes act as if it were daytime. The primary effect of being exposed to the abundant artificial light in our environment and in our buildings and homes is that it suppresses the production of melatonin in our bodies.
Melatonin is familiar to many people as a hormone that helps to regulate sleep and our body’s metabolic patterns. Scientists have found that a reduction of melatonin in the body increases the risk of obesity, and can also lead to the development of sleeping disorders[sc:1][sc:comma][sc:2].
Melatonin is also one of the substances that our body uses to naturally suppress cancer growth. It has been found that a reduction in melatonin in the body can lead to an increased risk of breast and prostate cancers[sc:3].
- Light pollution negatively impacts animals and plants
Natural sources of light regulate the biological functions of all life. When there is artificial light, these functions may be negatively impacted.
- Approximately half of the animals on our planet are nocturnal (primarily active at night), or crepuscular (primarily active at dawn and at dusk). The darkness of night time also indicates when many animals should eat, where to sleep, when to hunt, when to migrate, and when to reproduce. When there is artificial light at nighttime, these species are more exposed to predators, and have reduced time to find food, shelter, or mates, and to reproduce.
- As with human beings, artificial light suppresses the melatonin production of animals, negatively impacting their hormones, cells, genes, and organs, as well as their own biological clocks. This can negatively impact their behavior and natural activities, such as reproduction.
- Artificial light negatively impacts seasonal migration and reproductive patterns of wildlife, which depend on the natural lights of the sun, moon, and stars to determine where and when these activities should occur.
- White lights, such as metal halides, CFLs, and LEDs, emit large amounts of blue light that reduces the night vision of animals.
- Incandescent lights and high pressure sodium vapor lamps produce large amounts of reddish or infrared light. This interferes with the biological activities of many types of plants.
- Light pollution wastes energy, resources, and money
Many times, lights are shining at night, even when and where they are not needed. This is a waste of energy, producing unnecessary greenhouse gases in most cases, as well as a waste of money to pay for the energy that it wasted.
How you can help: 5 ways to help reduce light pollution
Turn off unnecessary lights outdoors and replace outdoor lights with low-glare versions. The International Dark-Sky Association certifies lights for low-glare and efficiency, and the company Starry Night Lights produces low light pollution lighting that is more environmentally-friendly.
Put exterior lights on motion detectors to reduce the unnecessary use of outdoor lighting, and direct illumination of lights towards the ground, not upwards (which is not efficient, and contributes to sky glow).
Use dimmer switches on household lights or use candles. At night, use dimmer switches in your home to reduce unnecessary lighting, or try using candles if you want to reduce your light pollution even further, and to encourage your own body’s winding down for the night. You might find that you like the effects, and appreciate the increased restful sleep of your entire family!
Also, if possible, consider eliminating your use of electronics a couple of hours before you go to bed to eliminate the blue light that such devices often emanate that may negatively impact your body’s own melatonin production.
Keep unnecessary lights off when going camping and staying in cottages because they can interfere with the health and the natural behavior of nocturnal animals like salamanders.
Talk to your family, friends, neighbors, and local and national governments about the impacts of light pollution on humans and the environment, and encourage practical changes and policies to help reduce light pollution in as many places as possible.