Category: Light Pollution

Light pollution affects many animals in our ecosystems that rely on the Earth’s cycle of natural light and darkness to survive. For many animals, light and dark signals to them when to eat, sleep, hunt, migrate, or reproduce. Some of these animals include sea turtles, bats, moths, birds, toads, zooplankton, wallabies, bees, and many more. Nocturnal animals sleep during the day and are active at night. The artificial light that we use is harshly disrupting their nighttime environment by essentially turning night into day. Diurnal creatures sleep at night and are active during the day, so the artificial light at night affects their sleep cycle, production of melatonin, and circadian rhythm just as it affects humans.

Sea turtles lay their eggs on beaches, and when they hatch, the hatchlings move away from the dark silhouettes of the sand dunes toward the brighter horizon of the ocean. However, many coastal areas are becoming heavily populated and these artificial lights are causing the sea turtles to go in the wrong direction. It leads them away from the safety of the ocean where they can experience dehydration, predators, or be run over by cars. Any reduction in the amount of artificial lights near beaches can help the safety of sea turtles.

Artificial light also attracts bugs. It is extremely harmful to these creatures because it acts as a vacuum that they cannot escape. Florida’s Fish and Wildlife Conservation Commission states, “Even one artificial light source can disrupt normal flight activity, long-distance migrations, or even attract insects that don’t normally move from their habitat.” When these bugs stay on the light for too long, they tend to die from overheating. Moths are typically the victim of this, which affects the birds and bats that feed on them because they lose a food source. Light pollution also affects the life cycle of plants and can prevent them from growing flowers and reproducing. This affects the pollinators of these plants and also their own life cycles. According to the National Academies Press’ Booklet “Resources on Pollinators,” one-third of human food requires a pollinator. Therefore, our food sources are being disrupted by light pollution.

Light pollution confuses nocturnal birds. These birds use the starlight and moonlight to navigate their routes. Artificial light from buildings can cause these creatures to be led astray and collide into them, leaving them injured for predators or to their deaths. They could also potentially circle their light source endlessly and could die from exhaustion.

Glare from artificial light affects amphibians, who detect light levels 100x dimmer than humans. Certain amphibians such as frogs and toads croak at night as a part of their breeding rituals. The light interferes with this process and disrupts their reproduction, therefore reducing their populations. Long exposure to artificial light also affects their hormones, skin coloration, and thermoregulation. Not only does light pollution affect the reproduction of amphibians, but it also affects the reproduction of wallabies. Artificial light causes wallabies to delay their births, which can be detrimental to their young because it puts them out of sync with the food that they need to feed their newborns.

Darkness is also required by certain animals for proper communication. Two examples are fireflies and coyotes. Fireflies emit a bioluminescent light from their bodies and it can range from adult mating signals to young larvae warning off predators. These messages can be often interrupted by unwanted and unneeded artificial light. It is also important for coyotes because they howl more during the time of a new moon when the sky is the darkest. Scientists believe they do this to reduce trespassing from other packs or to help with hunting larger prey during dark conditions. A bright sky reduces their howling, which could disrupt territorial marking and group hunting.

Light pollution also disrupts the reproduction of coral reefs. All coral reproduce in one way or another in correspondence with the moonlight. It is a very intricate and synchronized process in which the detection of moonlight intensity triggers vast numbers of coral and invertebrate species to release their eggs and sperm into the water. Failure to synchronize this annual event will reduce successful fertilization. The moon is a very important part of this process, and therefore the bright urban lights can mask the moon’s phases which throws the corals’ biological clocks out of sync.

Light Pollution Effects on Wildlife and Ecosystems

Pollinators

Plants and Light Pollution

Life on Earth Needs the Natural Rhythm of Light and Dark

In addition to hurting our environment and the lives of animals, many do not realize that light pollution also affects us. There have been studies proving that light pollution has negative effects on our own human health. Our bodies possess a physiological system called circadian rhythm, which is our biological clock based on a day-night cycle. This process stimulates brain wave patterns, hormone production of melatonin, cell regulation, and other biological activities. If your circadian rhythm is disrupted, it can result in health issues such as obesity, sleeping disorders, diabetes, depression, cancer, cardiovascular disease and more (Filmer).

The effects of light pollution can go beyond just sleep disorders. Light pollution suppresses the production of melatonin, which is a hormone produced in the dark hours of circadian rhythm. Melatonin is what helps keep our bodies healthy. It contains antioxidant properties, induces sleep, boosts our immune system, and lowers cholesterol; while assisting with the functions of the thyroid, pancreas, ovaries, testes and adrenal glands. Melatonin is related to cancer in several pathways, including effects on estrogen-receptor positive human breast cancer cells. Some studies have found a connection between exposure to artificial light at night and hormone-dependent cancers (Hill et al).

Many researchers believe that light pollution may be “carcinogenic” for humans. A study was conducted in 11 different Spanish regions and had compared those who were exposed to indoor versus outdoor exposure. The participants ranged in age from 20 to 85 from the years 2008 to 2013. Indoor exposure to light was determined by personal questionnaires, and outdoor exposure was evaluated based on nocturnal images taken by astronauts from the International Space Station. The study concluded that “both prostate and breast cancer were associated with high estimated exposure to outdoor artificial light at night in the blue-enriched light spectrum.” Compared to their control group, the participants exposed to higher levels of blue light had 1.5-times higher risk of developing breast cancer and 2-times higher risk of developing prostate cancer (Ariadna Garcia-Saenz et al).

Light pollution can, obviously, result in sleep disorders. Circadian disruptions can lead to a number of sleep disorders, including shift-work sleep disorder (SWSD) and delayed sleep-phase syndrome (DSPS). SWSD affects people who rotate shifts or work at night, and DSPS refers to people who fall asleep very late at night and have difficulty waking up in time for work, school, or other obligations. Artificial light in the bedroom- including blue light from cell phones, televisions, and laptops- is extremely harmful. It is recommended that these devices be taken out of the bedroom for the dark environment needed for sleep (Chepesiuk).

In a study published by Pediatric Research in August of 2006, they exposed newborn mice to constant artificial light for several weeks, in order to research the possible effects of artificial light exposure to developing circadian rhythms of premature babies in neonatal intensive care units. The exposed mice were unable to maintain a coherent circadian cycle at the age of 3 weeks, and mice exposed for an addition 4 weeks were unable to establish a regular activity cycle. The researchers concluded from this study that an excessive amount of artificial light exposure early in life might contribute to an increased risk of depression and other mood disorders in humans. The lead researcher Douglas McMahon stated that this data indicates that human infants benefit from the synchronizing effect of a normal light and dark cycle.

Glare- one of the three main types of light pollution, alongside light trespass and skyglow- is a public health hazard. Glare from poorly shielded outdoor lighting is harmful to our health because it decreases vision and can cause loss of contrast or sometimes blind you temporarily. This is especially a hazard at night and for aging eyes, which could potentially lead to unsafe driving conditions (Association of Universities for Research in Astronomy).

Unfortunately, the true causes of light pollution remain unknown and the research is not going at the pace that it should be. According to Susan Golden, a professor at the Center for Research on Biological Clocks of Texas A&M University, she says, “Light pollution is still way down the list of important environmental issues needing study. That’s why it’s so hard to get funds to research the issue.”

Light Pollution: How Does it Impact People? 

Evaluating the Association between Artificial Light-At-Night Exposure and Breast and Prostate Cancer Risk in Spain (MCC-Spain Study)

Missing the Dark: Health Effects of Light Pollution

Human Health

What is Light Pollution?

When your lights are on and you leave the room, do you shut them off or leave them on? Outside of your home, do you use motion sensor lights or lights that stay on all night? Leaving lights on when and where it is not needed is very wasteful. According to the International Dark Sky Association, in the United States alone for an entire year, outdoor lighting uses 120 terawatt-hours of energy to illuminate streets and parking lots. This is enough energy to meet New York City’s total electricity needed for two years! Their research states that 30 percent of all outdoor lighting in the United States is wasted, especially if the lights are not shielded. This adds up to be about $3.3 billion, which is enough money to fund an annual trip to Mars. This waste also causes the release of 21 million tons of carbon dioxide per year, which is adding to the problems of climate change. In order to make up for this release of carbon dioxide, we would have to plant 875 million trees annually. However, there are a few ways that we can help reduce this waste.

It is highly recommended that any outdoor lights for homes or illuminating streets use quality lighting. This could cut energy use by 60-70 percent and help save billions of dollars and cut carbon emissions. The International Dark Sky Association recommends installing LEDs and compact fluorescents (CFLs) because they can help reduce energy use and protect the environment. These lights help lower carbon emissions by reducing the demand for electricity. CFLs are very efficient, but it is complicated to calculate their conservation. The rule of thumb when using these lights is if you are leaving a room for less than 15 minutes, keep them on; but if you are leaving the room for more than 15 minutes, turn them off. The operating life of CFLs is affected by the number of times that it is turned on and off. LEDs are unaffected by the number of times you turn them on and off and have no negative effects on their operational lifetime. They are very small light bulbs that fit into an electrical circuit and do not have a filament that burns out, unlike the traditional incandescent bulbs. LEDs do not become very warm and emit a variety of colors such as red, yellow, green, or white lights. Only warm-white or filtered LEDs should be used. They produce the same amount of light and color rendition without emitting excessive amounts of blue light. These lights have improved in quality and fallen in prices, replacing many of the outdoor lighting in communities around the world. However, because LEDs are safer for the environment and do not use as much energy, do not give in to the temptation to over-light. You should continue to be shutting your lights off when they are not necessary.

Another way to reduce energy and light pollution is to make sure that outdoor lighting is fully shielded and direct light is only where it is needed. Fully shielded lights can produce the same amount of light on the ground as unshielded ones, but with less energy and cost. Outdoor lights should only be pointed downward and not toward the sky. When light is emitted into the sky, this is what causes sky glow. According to the Lighting Research Center, sky glow is of most concern to astronomers because it produces excessive light to dark areas of the sky and reduces their ability to view celestial objects. You should also use dimmers, timers, or motion sensors on your outdoor lights to ensure dark areas and save energy. This will make sure that lights are on only when necessary.

Another way to reduce the harmful costs of light pollution is to turn your lights off whenever you can. You must try to reduce unnecessary indoor lighting. This goes for office buildings, homes, and stores. Many office buildings keep their lights on at night. Use the sunlight to your advantage and try not to turn on lights during the day. Keep your curtains and shades open to provide natural light. Decorating and painting rooms with brighter colors helps to reflect the natural light.

Always remember, helping to reduce light pollution starts at your doorstep.

LED Practical Guide

The Energy Cost of Light Pollution

Light Pollution Wastes Energy and Money 

What is Sky Glow?

When to Turn Off Your Lights

The International Dark Sky Association has developed a program that protects areas of the world that have an exceptional quality of starry nights and nocturnal environment. They call them Dark Sky Sanctuaries and they are the best places to star gaze in the world. They differ from Dark Sky Parks and Dark Sky Reserves because the sanctuaries are typically in remote locations with very few threats to the quality of its dark skies and they do not meet the requirements to be a park or reserve. These sanctuaries are meant to encourage the protection of natural night skies around the world through the reduction of light pollution, public outreach and education, and to promote their long-term conservation. According to the IDA, there are only six sanctuaries in the program, these locations include Aotea/Great Barrier Island, New Zealand; Cosmic Campground, New Mexico; Devils River State Natural Area – Del Norte Unit, Texas; Gabriela Mistral, Chile; Rainbow Bridge National Monument, Utah; and Stewart Island/ Rakiura, New Zealand. In this blog, I will be focusing on the three sanctuaries found in the United States.

The Cosmic Campground is a site in Gila National Forest, New Mexico. It offers a clear 360-degree view of the dark night sky. According to the Cosmic Campground’s website, if you bring a flashlight, you must cover the light with a red plastic filter. If you look at a white light- i.e. car lights or a cell phone- you will not be able to view the natural sky for about 30 minutes. Red lights have longer wavelengths and are much easier on the eyes. White lights are a big culprit of light pollution, which is why we should reduce our usage of it. The website asks that their visitors not bring or use white flashlights, or put on car headlights after dark.

The Devils River State Natural Area- Del Norte Unit in Texas was once apart of a large working ranch. It is now surrounded by private ranches in a very remote location where its visitors are capable of seeing the beautiful and natural night sky. According to Texas Highways Magazine, this sanctuary was ranked a 1 out of 9- 1 being the darkest- on the Bortles Scale for having a very clear view of celestial objects with regard to light pollution and sky glow.

Last, but certainly not least, is the Rainbow Bridge National Monument in Utah. This bridge is one of the tallest and longest natural bridges in the world and was found to have cultural importance to a number of Native American tribes. The habitation of this area goes back thousands of years to tribes like the Hopi, Zuni, Navajo, San Juan Southern Paiute, Kaibab Paiute, and Ute Mountain Ute, who considered the bridge to be sacred. The bridge is located in an extremely remote area in difficult terrain, so the bridge remained unknown to civilization until 1909. The only way of accessing this location is by a two-hour boat ride on Lake Powell from marinas near Page, Arizona, then a mile long hike, or by hiking overland for several days from a trailhead on the south side of Lake Powell. It is said that the arch of the bridge is a symbol of the arch of the Milky Way stretched across the night sky, which is a reminder of the importance and value of the bridge and the natural night sky to the native peoples who inhabited that area.

On the International Dark Sky Association’s website, there are program guidelines for how a location can become qualified to be a Dark Sky Sanctuary. Some of these requirements include evidence of commitment to dark skies and quality outdoor lighting, a sky brightness measurement, a description of the current and future potential risks to the dark skies, and many more. The location must be nominated either by a member of the IDA or become a member and be self-nominated. They must apply to become an official Dark Sky Sanctuary.

Cosmic Campground Visitor Information

Texas Highways Magazine: Devils River State Natural Area

International Dark Sky Sanctuaries

Rainbow Bridge National Monument

2018 IDA Sanctuary Guidelines