What is Light Pollution?

By Joseph Chan 1SA1

Have you ever heard of light pollution? It is not a term that many are familiar with or have even heard of. However, like all types of environmental pollution, it is a persistent problem that has to be addressed. To illuminate upon its nature, light pollution is defined as the presence of artificial light in the night environment. It includes the light emitted by skyscrapers, lighted roadside advertisements, street lamps and other man-made sources of lighting. Although these individual sources are benign, when clustered together in large cities, they all give rise to light pollution. This is often exacerbated when light sources are utilised excessively. If you have ever sat in an airplane bound for a major city, and the airplane is about to land in the city airport, you would probably have noticed an orange or yellow hue engulfing the nearby buildings and structures. That hue is light pollution and its detrimental consequences are often underestimated.

Light pollution - Wikipedia
Light Pollution in the city

Environmental Effects

Light pollution is capable of disrupting entire ecosystems, especially those involving nocturnal animals. These animals require extremely dark environments to live in and are highly sensitive to changes in the natural light intensity of the environment. With light pollution, the lifestyles of these animals will be disturbed through a multitude of ways, such as affecting their ability to catch prey effectively and confusing their navigation. For example, there have been cases of sea turtle hatchlings wandering onto roads instead of heading into the sea because they mistook the light from lamp posts for moonlight. On that note, it should also be taken into account that nocturnal animals are not the only animals affected by light pollution. Even regular animals have suffered due to confusion over the time of day since many animals base their lifestyles around the diurnal patterns of light and dark.

Let there be light — but be mindful of the wildlife
Sea turtle hatchling heading towards the lamp post’s light

Night-blooming flowers have also borne the brunt of light pollution. These plant species are characterised by the unique feature of only blooming at night. With light pollution, these plants will be exposed to a light intensity level that is higher than expected during the night, preventing them from blooming. This restricts their ability to facilitate pollination and hence, reproduction, leading to the decline of such species and the ecosystems they are involved in.

Anthropomorphic(Human) Effects

Compared to other forms of environmental pollution, light pollution has a more significant direct effect on society itself. Medical research has shown that excessive lighting can have a physiological effect on us. According to research published by the European Commission, artificial lighting can lead to retina damage, disrupt our sleeping patterns and in extreme cases, increase our risk for developing skin cancer. Light pollution can also cause us to be less alert, increase our anxiety and make us experience fatigue more often.

Furthermore, with the night sky being increasingly blinded by the lights from major cities, there are fewer places on earth for us to observe the stars. Compared to the view from centuries ago, the present night sky hardly bears any resemblance. Stars that should have been easy enough to make out with the naked eye have been reduced to indiscernible specks in the black night sky. Not only are amateur astronomers denied the wonders of space, so are professional ones too. As a result, good observation sites are falling, with telescopes being increasingly built-in remote places away from the glaring cities. New technologies have to also be employed to filter out the excess light, providing numerous inconveniences to professional astronomers.

Lasers like this one, at the VLT in Paranal, help counteract the blurring effect of the atmosphere. Powerful arrays of much larger lasers could hide our presence from aliens. (ESO/Y. Beletsky)
Very Large Telescope in Cerro Paranal, Chile, over 100km away from any cities

Future for light pollution

Up to this point, there have been numerous efforts made to combat light pollution. New forms of lighting have been employed to light up cities, such as LEDs to reduce glare, special screens have been installed in public lighting to reduce light pollution and governments have been revising their lighting plans to efficiently employ public lighting. However, the special thing about light pollution is that we can make our own significant individual contributions towards minimising it, by turning off lights when we don’t need them, using energy-efficient light bulbs and restricting our usage of outdoor lights. With more innovative and experimental technologies being rolled out to combat pollution, it is important to remember that our own efforts can make a difference too, even if it is as simple as flicking a switch.

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Discover Magazine


Universe Today

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