Light Pollution: Understanding The Dark Side Of Artificial Lighting

Light pollution is a pressing issue that affects the environment, human health, and wildlife. Caused by the inefficient and unnecessary use of artificial light, light pollution is a human-made alteration of outdoor light levels from those occurring naturally. Sources of light pollution include street lamps, building exterior and interior lighting, advertising, commercial properties, offices, factories, and illuminated sporting venues. The effects of light pollution are far-reaching, with 83% of people, including 99% of Europeans and Americans, living under light-polluted skies. Light pollution has detrimental impacts on wildlife, such as migratory birds and sea turtles, and can also disrupt the sleep and circadian rhythms of humans. With no single country, group, or industry to blame, light pollution is a global issue that requires collective efforts to address.

Light pollution affects human health and wildlife

Light pollution, caused by the ever-increasing global reliance on outdoor electrical lights, has a significant impact on both human health and wildlife. The luminous orange glow that haloes cities and suburbs disrupts biological rhythms and interferes with the behaviour of nocturnal animals. It also wreaks havoc on the natural body rhythms of humans, affecting their sleep and overall health.

Impact on Wildlife

Light pollution poses a threat to wildlife, particularly bird populations. Nocturnal birds rely on the moon and stars for navigation during migration. When they fly through brightly lit areas, they become disoriented, often losing their way and dying. Sea turtles are also affected by light pollution. They need dark skies to orient themselves towards the sea, but artificial lights behind beaches lure them away from the water, making them easy prey for predators.

Light pollution also attracts and traps certain organisms, such as moths, frogs, and sea turtles, making them more vulnerable to predators. It repels other organisms, excluding them from their natural habitats. It also alters the day/night patterns of animals, disrupting their sleep and affecting their reproductive cycles.

In some cases, entire flocks of birds have collided with illuminated structures, resulting in mass casualties. For example, in 1954, 50,000 birds died over two nights at an Air Force base in Georgia, and in 1981, over 10,000 birds slammed into floodlights at a generating plant in Ontario. Seabirds, such as the Leach's storm petrel, are especially attracted to bright lights, putting them at risk of colliding with lighthouses, offshore drilling platforms, and high-intensity fishing lamps.

Impact on Humans

Light pollution can negatively affect human health in several ways. Research suggests that artificial light at night can disrupt the natural circadian sleep rhythm, leading to reduced sleep times, dissatisfaction with sleep quality, excessive sleepiness, and impaired daytime functioning. It has also been linked to an increased risk of obesity.

Additionally, light pollution has been associated with mental health issues such as depression. It can also cause visual discomfort, especially for older individuals, and limit the ability to see potential dangers at night. The intense, blue-rich LED lighting commonly used in outdoor settings can decrease visual acuity and create road hazards.

Furthermore, light pollution obscures the night sky, making it difficult for people in cities to observe the stars. This phenomenon, known as sky glow, occurs when artificial light from various sources, such as streetlights, offices, and advertising, scatters in the atmosphere, turning night into day. Sky glow not only affects stargazing but also the natural rhythms of both humans and animals.

Light clutter refers to excessive groupings of lights

Light clutter, a type of light pollution, refers to excessive groupings of lights. This includes redundant clusters of lighting found in many urban centres, such as badly designed street lights and overly bright advertisements. Light clutter can cause confusion, distract from obstacles, and potentially lead to accidents. For example, in areas where street lights are poorly designed or where bright advertisements surround roadways, the risk of accidents may increase.

Light clutter contributes to other forms of light pollution, including sky glow, trespass, glare, and over-illumination. Sky glow, one of the most pervasive forms of light pollution, is caused by artificial light reflecting off particles in the atmosphere, creating a bright haze over cities. This type of light pollution is particularly detrimental to astronomy and the health of many organisms, including humans, as it disrupts the natural day/night cycle and circadian rhythms.

Light trespass occurs when light extends into unwanted areas, such as a streetlight shining into a bedroom window. Glare, another form of light pollution, refers to excessive brightness that can cause visual discomfort, such as when driving. Over-illumination involves using excessive light where it is not needed. These types of light pollution can be mitigated by adjusting light fixtures, using appropriate light bulbs, and turning off lights when not in use.

Light clutter and other forms of light pollution have significant environmental, economic, and health impacts. It is estimated that 83% of the world's population lives under light-polluted skies, affecting the ability to view the stars and disrupting ecosystems. Additionally, the economic waste associated with light pollution is substantial, with one-third of all lighting wasted at an annual cost of $2.2 billion. Reducing light pollution requires community awareness and legislative action, as well as simple steps such as adjusting lighting practices and reducing the use of unnecessary artificial lighting.

Light trespass is when unwanted light enters one's property

Light pollution is a global issue, with no single country, group, or industry to blame. It is caused by the world's increasing reliance on outdoor electrical lighting. Light trespass is a specific type of light pollution. It occurs when artificial light enters a person's property from a neighbouring property, causing problems for those living or working in the affected spaces. Light trespass can originate from both residential and commercial properties.

Light trespass can be caused by a variety of artificial light sources, including floodlights, security lights, and decorative lighting. An example of light trespass is floodlights from a neighbouring property shining into the bedrooms and living spaces of nearby homes. This can negatively impact sleep and the enjoyment of interior spaces. Light trespass can also reduce privacy and increase energy costs for everyone.

To prevent light trespass, it is important to consider the positioning and design of lighting fixtures. Photometric analysis and appropriate lighting fixtures can help achieve the desired lighting levels while minimising light trespass. Solutions to reduce light trespass include changing the angle of security lights, installing sensor security lights that operate during specific hours, and minimising reflected light from windows by altering the colour temperature and wattage of external lights.

Local authorities have the power to enforce light trespass regulations and serve notices to residents or commercial property managers responsible for light trespass. Failure to address light trespass can result in legal implications and fines. Many locations have strict regulations against light trespass to protect the welfare of their residents.

Sky glow is the brightening of the night sky due to electric lights

Light pollution is a global issue, affecting both developing and developed countries. It is caused by the world's increasing reliance on outdoor electrical lights. While there are many types of light pollution, one of the most pervasive forms is sky glow.

Sky glow is the brightening of the night sky, mostly over urban areas, due to electric lights. Sources of sky glow include the lights of cars, streetlamps, offices, factories, outdoor advertising, and buildings. This phenomenon turns night into day for people who work or play long after sunset. The cumulative effect of these light sources creates a bright dome of light that covers most cities and towns and the infrastructure that connects them.

The impact of sky glow is twofold: it affects both humans and wildlife. For humans, the most obvious impact is the reduction in the visibility of stars and other celestial objects. In areas with high levels of sky glow, it can be difficult to see more than a handful of stars. This is particularly concerning for astronomers, whose ability to view celestial objects is severely limited by the brightened night sky.

However, the effects of sky glow go beyond astronomy. The brightening of the night sky can also disrupt the natural day/night cycle of 12 hours of natural light and 12 hours of darkness, which is essential to human biological welfare. This cycle is a part of our circadian rhythms, which are dramatically affected by the presence of light at night. Disruption of the circadian rhythm has been linked to various health issues, including sleep disorders, depression, hypertension, attention deficit disorder, obesity, diabetes, and heart disease.

Sky glow also has significant impacts on wildlife. Many species of birds and sea turtles, for example, instinctively follow the moon's glow to guide their migration patterns. Sky glow makes this less noticeable, causing them to get lost. Insects and small animals are also attracted to areas with more light, leading them towards cities and suburbs, where they can become a nuisance or even face death. Additionally, skyglow may interfere with trees' ability to detect seasonal changes, increasing their chances of being killed by an early frost.

To address the issue of sky glow, organizations like DarkSky Texas focus on educational and awareness events to help lawmakers and citizens understand the effects of sky glow and the importance of combating it to reduce sky brightness.

Light pollution is caused by inefficient or unnecessary use of artificial light

Light pollution is a pressing issue that affects humans, wildlife, and the environment. It is caused by the inefficient and unnecessary use of artificial light, which escapes into the environment and disrupts natural light levels. This can have detrimental effects on the health and behaviour of humans and animals, as well as contributing to air pollution and wasting energy.

Artificial light is generated by electricity, which is predominantly produced by burning fossil fuels. This process releases carbon dioxide and other emissions, contributing to air pollution and climate change. By reducing light pollution, we can help mitigate these environmental impacts.

Sources of light pollution include street lamps, parking lot and shopping mall lights, exterior lights on homes and businesses, neon signs, and illuminated signboards. Poorly designed or positioned lighting allows light to escape upwards into the sky, contributing to "sky glow", which brightens the night sky over urban areas. This disrupts the natural day-night cycle and affects the circadian rhythms of humans and animals, impacting sleep and other physiological processes.

Light pollution also causes glare, which can lead to visual discomfort and distraction, affecting the quality of life for many people. Additionally, it can disorient migratory birds and sea turtles, causing them to collide with buildings or lose their way, resulting in significant mortality rates.

To reduce light pollution, it is essential to use light efficiently and only when needed. This includes using shielded fixtures that direct light downward, reducing unwanted light trespass, and minimising glare. By adopting responsible outdoor lighting practices, we can help restore the natural nighttime environment and protect communities and wildlife from the adverse effects of light pollution.

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