Light Pollution: Who Is Responsible?

Light pollution is a pressing issue that is caused by the inefficient or unnecessary use of artificial light. It is a man-made phenomenon, resulting from the alteration of outdoor light levels from those occurring naturally. This pollution is particularly acute in urban areas, with over 80% of the world's population living under light-polluted skies. While there is no single country, group, or industry to blame, light pollution is a consequence of the global reliance on outdoor electrical lights. It has harmful effects on human health, wildlife, and the environment.

Light pollution is caused by humans and their inventions

Light pollution is a pressing issue caused by humans and their inventions. It is a side effect of industrial civilisation, with sources including building exterior and interior lighting, advertising, commercial properties, offices, factories, streetlights, illuminated sporting venues, and even boats and fireworks.

The alteration of outdoor light levels from those occurring naturally is a human-made phenomenon, impacting both humans and animals. Nocturnal light can interrupt sleep and confuse the internal, twenty-four-hour clock that guides day and night activities, affecting physiological processes in almost all living things. For example, light pollution can impact the migration patterns of birds and sea turtles, with bright lights causing them to lose their way and often die. Insects, a primary food source for birds and other animals, are drawn to artificial lights and are killed upon contact with the light source.

Light pollution also has ecological effects, wasting energy and increasing the impacts of climate change. It can be caused by inefficient or unnecessary use of artificial light, such as over-illumination, glare, light clutter, and light trespass. For example, light trespass occurs when unwanted light enters someone's property, causing problems such as sleep deprivation.

Light pollution is increasing globally, with 83% of people, including 99% of Europeans and Americans, living under light-polluted skies. This has resulted in a global movement to reduce light pollution, with organisations such as the U.S.-based International Dark Sky Association (IDA) working to preserve the natural night sky and reduce light emissions.

Overall, light pollution is a significant issue caused by humans and their inventions, with far-reaching consequences for both the environment and human health.

Light clutter: redundant clusters of lighting in urban centres

Light clutter, a type of light pollution, refers to excessive and confusing groupings of light sources that generate redundant clusters of lighting in urban centres. Light clutter is particularly noticeable in roads with badly designed street lights or bright advertisements. The arrangement of these lights can distract drivers and cause accidents.

Light clutter is a common issue in urban areas, where multiple light sources are placed too close together or are excessively bright. This can include street lights, advertising billboards, and illuminated buildings. These light sources can be distracting and confusing, especially for drivers, as they can make it difficult to see obstacles and navigate safely.

The impact of light clutter on driver safety is a significant concern. The placement and design of light sources can be intended to distract drivers, increasing the risk of accidents. Additionally, light clutter can contribute to visual discomfort and glare, further impacting the safety of drivers and pedestrians.

To address light clutter, many locales have implemented regulations for the arrangement of municipal lighting. These regulations aim to reduce the distracting and confusing effects of light clutter and improve safety. For example, urban areas near airports follow specific light arrangement patterns to avoid confusing pilots during night landings. Similarly, highways and large roadways use specially designed lighting patterns to minimise distractions for drivers.

Reducing light clutter can be achieved through careful planning and consideration of lighting schemes. This includes evaluating the placement, brightness, and proximity of light sources to avoid excessive groupings. By following manufacturer suggestions and planning unique lighting arrangements, individuals and organisations can minimise light clutter and improve the aesthetic and functional aspects of lighting.

Light trespass: unwanted light escapes from one property into another

Light trespass is a significant concern within the broader issue of light pollution. Light trespass occurs when unwanted light escapes from one property and intrudes into another, causing disturbances for neighbours. This can happen when light fixtures are improperly selected, installed, or aimed, resulting in light spillage beyond the intended illumination zone. For example, a streetlight shining into a nearby bedroom window or a neighbour's security light shining directly into another's bedroom.

The impact of light trespass can be more than just a nuisance. It can have detrimental effects on people's health and well-being. Studies have shown that artificial light can disrupt the natural body rhythms of both humans and animals, including sleep-wake habits and circadian rhythms. This can lead to sleep deprivation and other health issues.

To address light trespass, it is essential to choose outdoor lighting fixtures with proper optics and shielding. Shielded light fixtures direct light downward, confining it to the intended area and preventing light from escaping to surrounding properties. Adjusting the height of light fixtures, poles, and brackets can also help minimise light trespass by focusing the illumination where it is needed. Installing physical barriers, such as fences or netting, is another effective measure to block unwanted light from escaping.

In addition to these technical solutions, it is important to be a considerate neighbour. Communicating with neighbours about light trespass issues is a good first step. It is possible that they are unaware of the problem and may be willing to adjust their lighting to reduce the impact on your property. Mediation with a neutral third party can also help to generate solutions that meet everyone's needs.

Light trespass laws and regulations exist to control and minimise unwanted light spillage. Many states, municipalities, and cities have specific rules and standards to protect citizens' rights against light trespass. These regulations can include lighting ordinances, such as those developed by the International Dark-Sky Association, which aim to reduce light pollution and protect the visibility of the night sky.

Over-illumination: excessive light where it isn't needed

Over-illumination is the excessive and unnecessary use of light. It is a major contributor to light pollution, which is caused by the inefficient or unnecessary use of artificial light.

The Impact of Over-illumination

Over-illumination has a range of negative impacts. Firstly, it creates inefficiencies and increases costs for facilities in terms of energy consumption, labour, and maintenance. Secondly, it can cause eye strain and glare, leading to headaches, fatigue, medically defined stress, and decreased sleep quality, which further reduces employee well-being and productivity. Thirdly, it disrupts ecosystems, wastes energy, increases climate change impacts, and has adverse health effects on humans and animals. For example, it can affect the health of people and animals in the area, with studies showing that light pollution impacts animal behaviours such as migration patterns, wake-sleep habits, and habitat formation. Additionally, it can obscure the night sky, reducing the ability of astronomers to view celestial objects and impacting the natural night sky experience for others.

Causes of Over-illumination

There are several causes of over-illumination. One cause is the one-size-fits-all approach to lighting design, where the intended use of the space and the distribution of light are not adequately considered. This may result in too many luminaires being installed, leading to more light than necessary. Another cause is the blending of old and new lighting systems without properly accounting for the increased intensity of newer lights, such as LEDs. In older buildings, lighting schemes may not have been updated to match modern needs, resulting in more illumination than required for current working conditions. Additionally, the widespread use of artificial light in society has led to a lack of dark experiences, which can have negative consequences for retinal health and circadian rhythms.

Addressing Over-illumination

To address over-illumination, lighting designers need to tailor their designs to each individual space, taking into account the intended use, distribution of light, and the effects on the users of the space. Solutions to light pollution caused by over-illumination can include simple steps such as adjusting light fixtures, using more appropriate light bulbs, and educating the public to push for legislative change. Organizations like the U.S.-based International Dark Sky Association (IDA) are working to reduce light pollution by educating the public and certifying places that have reduced their light emissions.

Sky glow: light pollution over big cities, obscuring views of the night sky and harming humans and wildlife and the environment

Light pollution, specifically skyglow, has increased the brightness of the night sky, making stars appear dimmer or sometimes not visible at all. This phenomenon is caused by artificial light sources from cars, streetlamps, offices, factories, outdoor advertising, and buildings, illuminating the night sky. The cumulative effect of these light sources creates a bright dome of light that covers most cities and towns, obscuring our view of the stars.

Skyglow is particularly prominent over highly populated urban areas, with more than 80% of the world's population and 99% of Americans and Europeans living under its effect. It has severe consequences for humans, wildlife, and the environment. For humans, artificial light at night can disrupt natural body rhythms, interfere with sleep, and confuse the internal, twenty-four-hour circadian rhythm that guides our daily activities and physiological processes.

The impact on wildlife is also significant. Many species of birds, sea turtles, and insects rely on the moon's glow to guide their migration patterns. Skyglow reduces the visibility of the moon, causing them to get lost and disoriented, which can lead to their death. Additionally, large numbers of insects are drawn to artificial lights, leading to their instant death upon contact with the light sources. Even underwater life may be affected by artificial lighting.

To address the issue of skyglow and light pollution, organizations like DarkSky Texas and the International Dark Sky Association (IDA) are working to raise awareness, educate the public, and advocate for legislation that combats light pollution. Their efforts include promoting better outdoor lighting practices, supporting local lighting ordinances, and certifying places that have successfully reduced their light emissions. By recognizing the harmful effects of skyglow and taking collective action, we can help restore the natural night sky and mitigate the negative consequences of light pollution on human health, wildlife, and the environment.

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