In SPIN
Ireland's science wildlife and discovery magazine
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Science Spin March 2008
Blinding lights
By John Moore
The over use of articifical outdoor light, above our population centres, is causing the night sky to dim, or even disappear and to be replaced by a yellow-orange glow. Thus, the stars and galaxies that were once easily visible by the naked eye are now longer clearly visible. Tackling the issue of what's called 'light pollution' would, however, do more than enable us to again gaze in wonder at the stars. Such a move could also reduce our unecessary energy usage, thereby reducing our greenhouse gas emissions, while also serving to remove a threat to those animals and plants that are negatively affected by exposure to artificial light.
The over-use of artificial light above Ireland's population centres, as reflected in this image, is causing the night sky to dim or even disappear. Tackling the issue of 'light pollution', some argue, will mean that the stars will again be visible above our heads, carbon dioxide greenhouse gases will be reduced, and the cost of our lighting will also be reduced. Picture Credit: Irish Light Pollution Awareness Campaign.
Use of outdoor lighting for social and security needs today has become ever more important as we live and work during the hours of darkness. Turning night into day seems as natural to us as breathing, and in a way we've all become habitually complacent to its usefulness.
But there's a problem. It now seems that our over-eased use of artificial outdoor light is causing most of our darkened sky to disappear, literally, before our eyes. Instead of going downwards to where we actually need the light, a lot is spilling upwards into the sky causing it to glow.
Termed 'light pollution', this straying light, which emanates mainly from around cities as a faint yellow-orange glow in the sky, is robbing us of darkened skies, and affecting both nature and our environment. Most important of all, however, it has crept slowly into our 'sense of place' in the Universe, where stars and galaxies once easily visible by the naked eye have now become dimmed.
Pollution
"The main contributors are road and street lamps," said Albert White of the Irish Light Pollution Awareness Campaign based in Dublin. "Some have a glass bowl underneath that spreads part of the light upwards, however, by using a Full Cut-Off (FCO) lamp, which incorporates a flat piece of glass instead, most of the light can be kept from going above the horizon."
FCOs are currently used by the National Roads Authority in Ireland whenever a major road is being built, however, the ESB haven't fully committed to installing them everywhere. As most of the light goes down instead of out, using FCOs, lamp-poles would have to be put closer together, but as this means expense and disruption for the ESB, the distance between poles is currently left same, and their height is increased instead. While they have started to use a more shallower bowl replacement rather than using FCOs, these still aren't good enough to reduce light going upwards.
Light pollution, however, doesn't all have to fall on the ESB and their policies as most of us can make a contribution as well. By installing sky-friendly fixtures, reduce over-lighting and over-wattage, shield and turn outdoor lights off when not in use, we can significantly reduce its effects and the growing impact it has in areas like, for example, the environment and nature.
Environment
In the case for the environment: It's estimated that up to two billion tonnes of carbon dioxide is emitted into our atmosphere by power stations each year, while approximately two million barrels of oil per day is wasted in producing energy for over-lighting. Up to a third of these damaging effects could be knocked off if light pollution was taken seriously worldwide.
In the case for nature: By increasing the length of day using artificial lighting, the reproductive cycle and peak-body weight of some mammals can be affected, while in plants some cease to flower. "A number of animals and birds navigate using the moon and stars through astral navigation," said Dick Warner, well known environmentalist and nature specialist. "However, there is evidence that light pollution can affect this mechanism -- the most obvious example would be the effect it has on moths."
A German report in 2003 showed that a single streetlight would kill, on average, 150 insects per night. As these are a primary food resource for predators like bats, birds and frogs, the knock-on effect of over-lighting is increasingly putting strain on those higher up in the food chain.
Action
The counties of Dublin, Clare and Kerry have already incorporated some form of light pollution prevention into their Development Plans. The suggestions in these plans on how to tackle such pollution include discouragement of using floodlights, sensible illumination of buildings to not exceed a level of lighting that is necessary for safety and security, and any new applicants should include in their plans a lighting scheme of minimum requirement.
A light pollution policy has also been introduced in Armagh - home to one of Northern Ireland's leading astronomical research institutes, the Armagh Observatory. "We are organising the 9th European Symposium for the Protection of the Night Sky in 2009," said Professor Mark Bailey at the observatory. "In a year or so, I hope to begin a long-term programme to measure the varying brightness of the night sky in Armagh, and announce some results at the 2009 meeting."
Meanwhile, cities across Europe -- Italy, Belgium, Czech Republic, France and the latest, Slovenia -- are all in some way contributing to reducing light pollution. Ireland is making a small effort, but more still needs to be done. Wouldn't 2009 be a good date for the Irish Government to get involved more, and take some serious action in minimising light pollution across the whole island?
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