Light Pollution: Understanding The Causes And Their Impact

Light pollution is the human-made alteration of outdoor light levels from those occurring naturally. It is caused by unwanted, inappropriate or excessive artificial lighting, such as building exterior and interior lighting, advertising, commercial properties, offices, factories, streetlights, and illuminated sporting venues. Light pollution can have a negative impact on wildlife, including birds, pollinators, sea turtles, and mammals, as well as humans. It can also cause visual discomfort and disrupt the natural diurnal patterns of light and dark, impacting the ecological dynamics.

Overlighting

Light pollution is the human-made alteration of outdoor light levels from those occurring naturally. Overlighting is a major cause of light pollution, which can occur anywhere that unshielded light fixtures cause glare, light trespass, and upward scattered light. This can be caused by building exterior and interior lighting, advertising, commercial properties, offices, factories, streetlights, and illuminated sporting venues.

To reduce overlighting, it is important to use timers and sensors, and to choose the right colour of light. Organisations such as the U.S.-based International Dark Sky Association (IDA) are working to reduce light pollution and preserve the natural night sky.

Artificial light at night

Light pollution can be understood not only as a phenomenon resulting from a specific source or kind of pollution, but also as a contributor to the wider, collective impact of various sources of pollution. Although this type of pollution can exist throughout the day, its effects are magnified during the night with the contrast of the sky's darkness. It has been estimated that 83% of the world's people live under light-polluted skies and that 23% of the world's land area is affected by skyglow.

Cities and suburbs are the biggest contributors to light pollution, but rural places are not exempt. Overlighting can happen anywhere that unshielded light fixtures cause glare, light trespass, and upward scattered light. Massive oil and gas development projects are often located far from populated areas, but that doesn’t reduce their negative effects on wildlife.

Light pollution poses a serious threat to nocturnal wildlife, having negative impacts on plant and animal physiology. It can confuse animal navigation, alter competitive interactions, change predator-prey relations, and cause physiological harm. The rhythm of life is orchestrated by the natural diurnal patterns of light and dark, so disruption to these patterns impacts the ecological dynamics.

Poorly positioned lighting

Light pollution is the human-made alteration of outdoor light levels from those occurring naturally. It is caused by unwanted, inappropriate, or excessive artificial lighting.

Unshielded light fixtures can cause glare, light trespass, and upward scattered light. This can happen anywhere, not just in cities and suburbs. Overlighting can also occur in rural areas, such as with massive oil and gas development projects that are often located far from populated areas. This can have negative effects on wildlife, such as throwing birds off their migration paths.

Light pollution can have serious impacts on nocturnal wildlife, as it can confuse animal navigation, alter competitive interactions, change predator-prey relations, and cause physiological harm. It can also affect plants, for example by preventing zooplankton from eating surface algae, causing algal blooms that can kill off lake plants and lower water quality.

Glare

To reduce glare, it is important to use shielded light fixtures that direct light downwards, rather than allowing it to scatter upwards. This not only reduces light pollution but also improves the efficiency of lighting by reducing wasted electricity.

Clutter

The negative effects of clutter are not limited to urban areas. Massive oil and gas development projects, often located far from populated areas, can also create clutter and negatively impact wildlife. Artificial light at night can disrupt the migration patterns of birds, causing them to circle bright natural-gas flares and lose significant amounts of body weight.

To address the issue of clutter, organisations such as the International Dark Sky Association (IDA) are working to reduce light pollution. By advocating for better lighting practices, such as the use of timers, sensors, and appropriate colours of light, these organisations aim to minimise the negative impacts of clutter on both the natural environment and human health.

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