Dark Sky Reserve Networks Usher in Earth Law
Figure 1 Stars over Rocky Mountain National Park, US. Photo by Jeremy Thomas on Unsplash
Updated by Bode Wolin (March 2025)
If you’ve ever tried to see the stars at night, you may have found it nearly impossible. So much light floods our night skies that the term “light pollution” has emerged, describing any adverse effect of artificial light. Such effects in our modern night skies include sky glow, glare, light trespass, light clutter, decreased visibility at night, and energy waste.
In 2016, data found that one third of the world’s population cannot see the milky way at night, including a large number of Americans and Europeans without access to a pristine, dark night sky.
Main types of light pollution
The three main types of light pollution are glare, light trespass, and skyglow.
Glare from unshielded lighting is a public health hazard—especially the older you become. Glare light scattering in the eye can cause a loss of contrast and temporary blinding, which can lead to unsafe driving.
Light trespass occurs when unwanted light enters one’s property. Shining unwanted light into a bedroom window of a person trying to sleep, for example.
Skyglow refers to the glow effect that can be seen over populated areas. Skyglow is the combination of all the reflected light and upward-directed, or unshielded, light escaping up into the sky. For the most part, this escaping light goes unused.
Shielding lights significantly reduces all three of these types of light pollution, as well as helping with over-illumination and clutter in our night skies.
Figure 2 Sky glow. Griffith Observatory, Los Angeles US. Photo by Denys Nevozhai on Unsplash
What’s the problem with too much light?
Light pollution affects many animals since light and dark often act as signals for when to eat, sleep, hunt, migrate, or reproduce. Lack of these signals thus alters and interferes with the timing of necessary biological activities. Artificial light at night disrupts nocturnal pollination networks, meaning negative consequences for reproductive success in plants. In one study of artificially illuminated plant-pollinator communities, nocturnal visits to plants were reduced by 62% compared to dark areas.
Could light pollution be contributing to the decline of coral reefs? More than 130 different species of coral on the Great Barrier Reef spawn new life by moonlight. Every October or November after the full moon, coral polyps release sperm and eggs into the ocean in what looks like an underwater blizzard. When the two sex cells combine amid the flurry, fertilization begins. Bright urban lights can mask the moon’s phases, throwing the corals’ biological clocks out of sync, according to Oren Levy of Bar-Ilan University. This can cause the reefs to release their reproductive cells late or not at all, decreasing their chances of producing offspring.
Since most songbirds migrate at night, light pollution disrupts their circadian rhythms and can disorient birds during migration. Bright lights at night on large buildings attract birds in the same way that bright porch lights attract moths, which can result in fatal collisions.
Figure 3 Baby sea turtle. Wildlifeppl at en.wikipedia
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 draw the baby sea turtles away from the safety of the ocean towards land where they can suffer dehydration, encounter predators, or be run over by cars. Any reduction in the amount of artificial lights near beaches can help protect newly hatched sea turtles.
Florida’s Fish and Wildlife Conservation Commission explains these cycles, “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 victims, which in turn 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, further changing and harming the life cycle of pollinators, and humans. According to the United States Department of Agriculture, one-third of human food requires a pollinator.
Amphibians are an important part of forest and aquatic ecosystems; and because they are very sensitive to environmental changes, they serve as an important indicator species of the health of ecosystems. Environmental stressors have caused their populations to decline around the world, and light pollution may play a big part by changing both foraging and breeding habits of nocturnal amphibians.
Zooplankton called Daphnia normally dwell deep underwater in the day and ascend to the surface at night to feast on algae. Darkness triggers their migration. But marine ecologists have found that nighttime lighting can prevent the zooplankton from floating up for their meals, which could lead to algae blooms that overwhelm the other life in a lake.
Trees evolved with regular day to night cycles so they can measure light with a kind of molecular clock. This clock tells them how long the sun is out, which season it is, and the distance from other trees measured by the length of shadows that are cast. From this information, trees decide when to photosynthesize, when to send out leaves in spring, leaf color, and when to shed leaves. Artificial light wreaks havoc with this system by extending the length of a day, which changes flowering patterns and energy storage capacity for the winter months.
Humans, too, need natural darkness for sound sleep and good health. Cool blue-white light at night from LED, fluorescent, and metal halide lights interferes with the body’s circadian rhythms by suppressing melatonin and increasing cortisol, a brain chemical released when we are stimulated or excited. High cortisol levels make it difficult to fall asleep or experience deep sleep, which our immune systems need to fight illness and disease.
What’s being done to reduce light pollution?
Light pollution is one of the easiest pollutions to clean up. Taking steps to reduce light pollution doesn't mean living in the dark - it's about making light more efficient and beneficial.
Dark Sky Reserves
An International Dark Sky Place is a public or private land area possessing an exceptional or distinguished quality of starry nights and nocturnal environment that is specifically protected for its scientific, natural, educational, cultural, heritage and public enjoyment. Reserves consist of a core area meeting minimum criteria for sky quality and natural darkness, and a peripheral area that supports dark sky preservation in the core. Currently, there are over 160,000 square kilometers of protected land and night skies in 22 countries on 6 continents. Dark Sky International curates a list of certified dark sky parks, and serves as a database and hub for more information on the dark sky movement, advocacy and educational opportunities, and light pollution-reducing statutes.
Figure 4 Mama and baby Grizzly bears in Jasper Park. Photo by Michelle Bender, used with permission of author.
The first gold-tier dark sky preserve in the United States, the Central Idaho Dark Sky Reserve in the U.S. state of Idaho includes the 1,416-square-mile (3,670 km2) Sawtooth National Recreation Area. It was designated on December 18, 2017. The rugged terrain has prevented much infrastructure development in the area, and is one of the last areas in North America where you can clearly view the Milky Way with the naked eye.
Another dark sky darling, Jasper National Park, sits in Alberta’s Rocky Mountains. “Jasper is one of 17 designated Dark Sky Preserves in Canada,” says Myriam Bolduc, marketing manager for Tourism Jasper. “At 11,000 square kilometers, we are the second largest Dark Sky Preserve in the world, and we are the largest accessible Dark Sky Preserve—meaning there’s a town within the limits of the preserve.” The Royal Astronomical Society of Canada (RASC) delineates the dark sky buffer zones around the preserve and hosts the world-renown Dark Sky Festival annually in October.
To become a Dark Sky Preserve, the Jasper area had to eliminate visible artificial lighting while putting measures in place to educate the public and nearby towns about light pollution. The sky glow from outside the border of the preserve had to match that of a natural sky glow. Today, 97 percent of the park is a designated wilderness area, free of light pollution, with roads and trails providing easy access to year-round stargazing sites.
Governments Act to Reduce Light Pollution (and energy costs)
From 2014-2016 the US Department of Energy’s Outdoor Lighting Accelerator (OLA) worked with three states, 16 cities, and 6 regional energy networks committed to upgrading 1.3 million street lights. The modifications are projected to save cities an estimated $48 million/year and vastly reduce light pollution.
As of 2025, at least 17 states in the US, Puerto Rico, and D.C. have adopted laws or statutes regulating nighttime lighting, but local governments and cities must lead the way for regulation in order to create a more comprehensive space for mitigating light pollution.
Across the pond, the European Union adopted new roadway lighting guidelines, employing an ‘As Low As Reasonably Achievable‘ (ALARA) principle. The specific guidelines, intended to reduce energy use as well as light pollution, are consistent with the Low Impact Lighting (LIL) standard promoted by German, Italian and Slovenian members of the European Environmental Bureau in the past decade.
Recently, the European Union has adopted light pollution as one of their priority environmental issues, establishing a comprehensive policy document in 2023 known as the European Light Pollution Manifesto.
Many U.S. cities have taken the lead in re-doing their lights to reclaim the night and decrease energy waste. Flagstaff, Arizona, was the first city to be designated a Dark Sky Community by the International Dark-Sky Association, and Chicago is in the process of retrofitting its fixtures, as well as mapping light pollution across its metropolitan area. So far, concerns about dimmer, sparser lighting possibly causing an uptick in crime or decreased safety at night have not been supported by the data; in Chicago’s West Garfield Park, more brightly lit alleys actually led to an increase in reported crime. When it comes to human nightvision, our eyes adapt more quickly to the dark in the absence of glaring lights.
Figure 5 Different levels of light shielding. Created by ELC for this blog.
What cities can do to reduce light pollution
Motion sensitive street lighting has become a reality on many streets across the world. Lights come on as people and moving objects approach, illuminating an area in advance and turning off after a period of no motion being detected, reducing wasted light and wasted energy.
Street lighting that is encased above and to the sides channels light downwards – only where it is needed, like a spotlight – and reduces the amount of wasted light. Known as ‘cutting off light at the horizontal’, this ensures that light is used to illuminate the ground, not the sky.
Switching to low-watt bulbs is a straightforward way of reducing light pollution. Moving away from bluish-white lighting could be a big contributor to reducing light pollution in an urban areas. Replacing LED lights with warm, white lighting creates a win-win situation. In Switzerland, 460 cities that make up 60% of the Swiss population have drastically changed their lighting infrastructure to smart lighting systems engineered for automatic dimming and motion sensor activation.
What individuals can do to reduce light pollution
Install reflectors to outline a driveway instead of putting in a row of lights. Reflectors are cheaper to purchase, free to use, and are unaffected by power outages.
Dimmer switches on household lights, both indoor and outdoor save energy and reduce light pollution
Eliminate, reduce or turn off late night decorative lighting and/or outdoor lighting during late night hours when outdoor areas are not in use.
Some power companies bill you for “Nearby Outdoor Lighting” which could mean the lamp across the street. Check your bill for the $5 - $10 a month for this service and call to ask for the charge to be terminated and the light be removed.
The IDA Fixture Seal of Approval for dark sky friendly fixtures which minimize glare, reduce light trespass, and keep the night sky dark.
Earth Law as an additional solution to light pollution
Earth Law Center is building an international movement from the ground up, one that gives a better grounding to the idea that humans have a responsibility for how we impact the world around us. The belief that nature - the species and ecosystems that comprise our world - has inherent rights has proven to be a galvanizing idea, and we work with local communities to help them organize around the rights of nature to protect their environment from the threats that they see and prevent future harms or risks.
The heart of the ELC approach is to seek legal personhood for ecosystems and species, a designation similar to that given to corporations in U.S. law. It implies both the rights for the designated entities and the responsibilities on the part of human beings and societies to respect those rights.
Our work includes helping governments adopt and implement laws, policies, and practices that protect other species, ecosystems, and the elements of the natural world: water, air, and land. Our work also includes providing education about how individual people and communities can live better as part of Nature and as its stewards, rather than its masters.
Restoring natural Dark Skies is consistent with our commitment to take a more holistic view of ecosystems and fellow species by respecting the rights of all living things to exist, thrive, and evolve.
Here’s more you can do: