The dark side of light | Sunday Observer

The dark side of light

4 April, 2021

The electric light, one of the everyday conveniences that mostly affects our lives was invented by Thomas Alva Edison in 1879. He was neither the first nor the only person trying to invent an incandescent light bulb.

In fact, some historians claim there were over 20 inventors of incandescent lamps prior to Edison’s version.

However, artificial light production has increased rapidly through the last two centuries, and the pace of those changes has been accelerating in the last decades.

Most of us are familiar with air, water, and land pollution, but did you know that light can also be a pollutant?

Light Pollution or the Dark Side of Light, which will address the physical causes of light pollution and its consequences for biodiversity, energy expenditure, human health, and scientific and cultural knowledge.

The inappropriate or excessive use of artificial light known as light pollution can have serious environmental consequences for humans, wildlife, and our climate. Components of light pollution include Glare(excessive brightness that causes visual discomfort), Sky glow (brightening of the night sky over inhabited areas), Light trespass (light falling where it is not intended or needed), Clutter (bright, confusing and excessive groupings of light sources), Over illumination (the excess supply of light used beyond what is necessary for safety and efficiency). Light pollution is a side effect of industrial civilization. Its sources include building exterior and interior lighting, advertising, commercial properties, offices, factories, streetlights, and illuminated sporting venues.

The fact is that much outdoor lighting used at night is inefficient, overly bright, poorly targeted, improperly shielded, and in many cases, completely unnecessary.

This light, and the electricity used to create it, is being wasted by spilling it into the sky, rather than focusing it on to the actual objects and areas that people want illuminated.

For three billion years, life on Earth existed in a rhythm of light and dark that was created solely by the illumination of the Sun, Moon and stars. Now, artificial lights overpower the darkness and our cities glow at night, disrupting the natural day-night pattern and shifting the delicate balance of our environment.

The negative effects of the loss of this inspirational natural resource might seem intangible. But a growing body of evidence links the brightening night sky directly to measurable negative impacts including disrupting the ecosystem and wildlife, harming human health, increasing energy consumption and effecting crime and safety.

The effect called sky glow or radiance of the sky is the result of the reflection and dispersion of artificial light by clouds, aerosols, and particles suspended in the atmosphere.

The dispersion propagates the effects of light pollution at distances beyond the position of the original source of light, illuminating the night sky in its entirety and forming a kind of luminous dome or dome of light when observed from a certain distance.

Less than 100 years ago, everyone could look up and see a spectacular starry night sky.

Now, millions of children across the globe will never experience the Milky Way where they live. The increased and widespread use of artificial light at night is not only impairing our view of the universe, it is adversely affecting our environment, our safety, our energy consumption and our health.

Light pollution is threatening the night sky, a phenomenon that has left the Milky Way invisible to one-third of the world’s population. It’s a problem affecting 80 percent of Earth’s population, if we do not take precautions, next generations will see the Milky Way from books only.

The disappearance of the night sky is an unprecedented situation in the course of human history. Light pollution began to be recognised as a pressing problem about 45 years ago by astronomers who witnessed a progressive deterioration of the night sky quality at some of the leading astronomical observatories of the time.

Light-polluted skies

Recent studies suggest that light pollution has increased worldwide by roughly 2 percent a year between 2012 and now, so the problem is already becoming bigger every day.

With much of the Earth’s population living under light-polluted skies, over lighting is an international concern.

If you live in an urban or suburban area all you have to do to see this type of pollution is go outside at night and look up at the sky. Some 80 percent of the world’s population lives under sky glow.

In the United States and Europe 99 per cent of the public can’t experience a natural night! When we consider the environmental effects, light pollution disrupts the cycle of light and darkness produced by the rotation of the planet, plants and animals whose DNA is encoded with the natural rhythm of day and night are at risk.

Light pollution affects a wide variety of living organisms, including mammals, birds, reptiles, fishes, insects, and even micro- organisms in unanticipated ways, causing adverse effects on the environment and the ecosystem.

Scientific studies show that light pollution interferes particularly in the behavior of migration and reproduction of various types of creatures, which will eventually threaten biodiversity.

The sky glow can also affect the habitats of wetlands that harbor amphibians such as frogs and toads, whose nocturnal croaking is part of their mating ritual.

In addition, the decrease in populations of some insects attracted by excessive lighting negatively affects all the species that depend on them for food or pollination.

Several animal species have been documented to be affected by light pollution.

The glare of street lights cause distraction to nocturnal birds in flight leading to bird crashes into sky scrapers and buildings. The use of light may also cause birds to reproduce or migrate too early.

The feeding behaviour of insects, bats, sea turtles, fish, replies reflect alterations by artificial light. Sea turtles mistake the glow of electric lights for the shimmer of the ocean, leading them to flock outside of their nest into hazardous areas.

Exposure to light during traditional sleeping hours have are documented to cause disruptions in the circadian rhythm that regulate human sleep cycles.

Biologists have noted a decrease in the amount of melatonin, a natural hormone that regulates the Circadian rhythm, in humans that are exposed to light pollution of the night sky.

To prevent major impact, biologists suggest to increase the amount of natural light exposure during the day and decrease the amount of electrical light consumed at night.

The growing pattern of trees have been disrupted and less adjusted to seasonal changes in weather and light exposure.

Artificial light at night has revolutionised the way we live and work outdoors, but it has come at a price. When used indiscriminately, outdoor lighting can disrupt wildlife, impact human health, waste money and energy, contribute to climate change, and block our view of the universe.

The International Dark-Sky Association promotes win-win solutions that enable people to appreciate dark, star-filled skies while enjoying the benefits of responsible outdoor lighting.

We as a society need to decide if light pollution is something we care about. That’s the only way to effectively address the problem, by passing and enforcing local and regional lighting ordinances to protect the night sky in our communities.

Light pollution affects every citizen. Fortunately, concern about light pollution is rising dramatically. A growing number of scientists, homeowners, environmental groups and civic leaders are taking action to restore the natural night.

Each of us can implement practical solutions to combat light pollution locally, nationally and internationally. The International Dark-Sky Association said the problem can be tackled on large and small levels beginning with persons making smart lighting choices.

People can take action with simple measures that go a long way to mitigate light pollution such as using warmer LED and compact fluorescent lamps with a color temperature under 3000 K.

It’s important to install outdoor lighting fixtures that shield the light source to minimise glare and light trespass, directing their light onto the ground. Also, unnecessary outdoor lighting should be reduced by using dimmers, motion sensors, or timers.

On the larger scale, state and Local Governments need to get involved to be part of the solution. Today’s youth and future generations are not the solution, because unlike other forms of environmental pollution, it’s not a technically difficult problem.

In the end, we just need cultural change. The solutions are already at hand. It is the responsibility of the current generation to make changes that will counter the trend.

The light pollution problem is continually getting worse, just as with any other environmental problem, waiting for future generations to take care of it would be incredibly lazy and reckless on our part.

As a matter of fact, we owe our descendants dark skies without light pollution. Modern society requires outdoor lighting for a variety of needs, including safety and commerce, but any required lighting be used wisely.


To minimise the harmful effects of light pollution, lighting should only be on when needed, only light the area that needs it, be no brighter than necessary, minimise blue light emissions, be fully shielded and pointing downward.

Only use lighting when and where it’s needed. If safety is a concern, install motion detector lights and timers. Properly shield all outdoor lights. Keep your blinds drawn to keep light inside. The good news is that light pollution, unlike many other forms of pollution, is reversible and each one of us can make a difference! Just being aware that light pollution is a problem is not enough; the need is for action.

You can start by minimising the light from your own home at night.

You can do this by following simple steps. Then spread the word to your family and friends and tell them to pass it on. Many people either don’t know or don’t understand a lot about light pollution and the negative impacts of artificial light at night. By being an ambassador and explaining the issues to others you will help bring awareness to this growing problem and inspire more people to take steps to protect our natural night sky.