Image Generated with AI ∙ 29 November 2023 at 1:05 pm
The Impact of Excess Light on Other Species
Humans aren’t the only ones to have a problem with too much light. The lifecycles of other species including mammals, frogs, birds and insects can also be affected. Many of our native animals are nocturnal. Excess light may prevent them from feeding or expose them to predators. In the case of at least one species, the tammar wallaby, artificial light can disrupt its breeding cycle.
Birds which use starlight to navigate often become confused and disoriented when confronted by urban lighting. Tall, well -lit structures such as office buildings and oilrigs may cause injury and death. Many insects and bats are also fatally attracted to light. Remember when our windscreens used to bristle with moths and other insects after a drive at night? Species such as glowworms and fireflies use their lights for to attract mates, or in the case of glow worms, to attract food, and have trouble being noticed when there is too much light. Turtles and their hatchlings are especially vulnerable as you can see in this video.
Strip lighting along freeways can also create an artificial barrier between areas and fragment habitat, which also makes it more difficult for animals to breed.
Impact on Plants and Soils
Even plants can be affected. Without the animals and insects which help with seed dispersal and pollination, they do not reproduce in their usual numbers. Marine species are also drawn to or repelled by light. In artificially lit lakes, zooplankton no longer dines on surface algae, contributing to algal blooms and poor water quality. Reduced activity by invertebrates such as beetles and bacteria which help in the breakdown of organic material and soil production can also disrupt whole ecosystems. [Pleasantly surprised to see Australia right at the forefront of this research].
Other Problems created by Light Pollution
In our cities, light spills from office buildings, advertising signs, street lights and garishly lit shop windows. According to The Globe at Night Organisation which is dedicated to raising awareness about Light Pollution and gathers data from around the world, Light Pollution is defined as “excessive, misdirected or obtrusive light which alters the natural conditions of the night sky.” Here are some more reasons why it’s a problem.
When less light is better
It would be easy to think that more light would make cities safer, but you’d be wrong. As Stuart, our guide pointed out, ultra bright light such as the flood lights which have now been installed along the waterfront at Salamanca, actually have the opposite effect. Our eyes have difficulty adapting to extremes of light and in places where muggings are common, nefarious activity takes place in the now much darker spaces between lights.
Humans can see perfectly well by as little as one Lux – the equivalent of a moonlit night, provided that that light is even. Indeed, on the way back to the car, I passed through a park. Though only softly lit, I could see over vast expanses of grass, trees and bushes to the edges of the park and would have noticed any movement, whereas bright lights may have illuminated the path and the foreground, but not given me that depth of field. It certainly demonstrated that night vision improves in lower light.
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| Our eyes have difficulty switching between light and dark. When lights are too bright they dazzle rather than allowing us to see details. Colours are washed out, and why are we illuminating the tree tops? |
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| Another example of poor lighting. It doesn't need to be so bright and it is unshielded, meaning that much of the light is thrown upwards where it does harm rather than good |
Also counter -intuitive is the fact that, according to Stuart, adding more light in order to
attract more people to an entertainment precinct can have the opposite effect, especially
with respect to young people. Any bright light makes the surroundings appear even darker.
Road Safety Issues
The reason the French are looking hard at headlights, outdoor advertising and billboards is precisely because they distract drivers, cause confusion when there are too many or they are too bright, or create glare – visual discomfort, all of which can contribute to accidents.
Interference with Astronomical Observation
The combined effect of street lighting, commercial and domestic lighting and security lights, produces “Sky Glow” - that dome of light which surrounds cities and prevents us seeing phenomena such as Auroras, Meteor Showers and manifestations such as STEVE – ribbons of light similar to, but not exactly like Auroras, which have only recently been recognised. It also prevents general astronomical observations. It is precisely the absence of extraneous light – and generally good weather, which makes outback Australia an ideal place for stargazing and monitoring of space exploration missions.
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| Night time Sky Glow over Washington D.C. |
Cost and Energy Savings
The Globe at Night organisation notes that lighting accounts for one quarter of global energy consumption. Reducing unnecessary lighting would thus in most instances not only reduce our carbon footprint if its power was coming from fossil fuels, but result in considerable savings for individuals and communities.
As an example, The International Dark Sky Association which campaigns for light - free spaces, has noted that light pollution costs the city of Quebec an estimated $50 million per year. [Data from Astro Canada, reported in Let's Talk Science].
The Right to Starlight
With more than 80% the world’s people now living in cities, many have never had a chance to experience the night sky free of light pollution. It is a thing of beauty, the stuff of poetry, romance and creativity and also shows us our place in the universe. I have no scientific evidence for this apart from the physiological studies about the impact of excess light on our health and mental wellbeing, but I believe we need the night as much as the day for our inner growth, to process what we have seen and learned, and simply to pause and wonder.
We worry about chickens being constantly bathed in artificial light to increase their egg production though it shortens their lives, yet we don’t worry about humans. We are living creatures after all, whether we want to believe that or not. Great works (and mischief) are created in the dark, not when we are busy, busy all the time. To me, the night is when the earth and nature stop to catch their breath. Why shouldn’t we do likewise? Anyone who has spent any time at all under a clear night sky will know what I mean.
Let's finish off with this quote;
“The true joy
of a moonlit night is something we no longer understand. Only the men of old,
when there were no lights, could understand the true joy of a moonlit night.”
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