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Sep 3, 2014 · Ecosystems: Everything is connected. In addition to their ecological role, fireflies are a source of wonder and delight for children and adults. Many insects are drawn to light, but artificial lights can create a fatal attraction. Declining insect populations negatively impact all species that rely on insects for food or pollination.
A 2017 follow-up report found that global light pollution levels are rising at a rate of 2.2 percent a year. For every human stargazer who bemoans the disappearance of the Milky Way, light pollution disorients countless animals, exposing many to dangers such as predators, exhaustion and starvation.
Disruption of Circadian Rhythms. One of the most significant impacts of light pollution on wildlife is the disruption of their circadian rhythms. These are the internal clocks that regulate physiological and behavioral patterns in animals. Many species rely on the natural cycle of day and night to regulate their sleep, feeding, and mating ...
Apr 20, 2015 · According to the International Dark-Sky Association (IDA), the term light pollution refers to “any adverse effect of artificial light, including sky glow, glare, light trespass, light clutter, decreased visibility at night, and energy waste.” The IDA further states that light pollution “wastes energy, affects astronomers and scientists, disrupts global wildlife and ecological balance ...
- Overview
- How light pollution harms the environment
- Turn off, dim, and shield your lights
- Cities going dark
It’s not just about seeing the stars. Bright city lights disorient animals like birds, leading to fatal collisions and potential long-term damage to their health.
The city lights of La Paz, Bolivia light the night sky. Artificial light shining from buildings, cars, and street lamps can be fatal for some wildlife.
Look for a constellation in the glow of a city, and at best you might see a star or two. That’s because light pollution is turning night into day in 80 percent of the world.
The day to night cycle is an essential part of nature, telling animals when to emerge to hunt, forage, migrate, and mate. When artificial light disrupts those natural light cues, wildlife from bugs to birds, and even plants, are seriously impacted.
It’s a problem getting worse every year, but there are simple solutions to help wildlife and restore our night sky view, experts say.
“When we look at the sky and we can’t see the stars, it’s a sign that our lighting is poorly designed and wasteful,” says Christopher Kyba, a physicist at the GFZ German Research Center for Geosciences.
A report from last year examined over 160 species of plants, fish, mammals, and insects to understand how our artificial lights are changing ecosystems. Researchers found that animals look to light via the rising and setting of the sun and moon to determine when to emerge from their hiding places to hunt, forage, migrate, and mate. All manner of wildlife is affected—for example, some bugs can be more easily preyed on and some birds fly off course.
“For all of evolutionary history there was a stable pattern—any animal or plant can anticipate day and night,” says Kyba. “But when we add a bunch of artificial light, obviously that’s going to mess things up.”
Fireflies use light to signal to potential mates at night. But city and suburban lights outshine these cues at alarming rates. One study published in 2020 suggested light pollution, along with habitat loss and pesticide use, could put some of the world’s 2,000 different firefly species at risk of going extinct.
Left: From above, Chicago's lights shine brightly. Reducing light pollution shining out of Chicago's buildings by half could reduce the amount of bird deaths resulting from birds colliding with buildings, one study found.
Right: A leatherback turtle struggles ashore to lay her eggs. Light pollution deters them from coming ashore to their nesting sites.
Photographs by JIM RICHARDSON, Nat Geo Image Collection
Unlike removing pollution from the air or water, light pollution can be eliminated immediately. Reducing light pollution can be as simple as turning off the lights, installing motion sensors that limit when lights are on, or adding dimmers that reduce the light coming from a single bulb.
“The best part of a lot of these [solutions] is they save everyone money,” says Alaasam. “If you can turn off lights more often, it saves electricity and [reduces carbon emissions] and it’s kind of a win-win.”
Energy efficient LED light bulbs are cheaper and longer-lasting than their incandescent predecessors, but their widespread adoption has caused problems for wildlife. LED bulbs produce a short-wave blue-tinted light that attracts more insects and birds and disrupts circadian rhythm in mammals. But bulbs with yellow-tinted filters can minimize these impacts.
“The kind of light we use really matters,” says Alaasam. “For birds, if you use a warmer, yellower hue, you don’t see nearly as many effects.”
Shielded coverings for street lamps and outdoor lights help concentrate light directly down to where we need it, preventing it from leaking out and up.
Simply closing your blinds and curtains can also help prevent artificial light from shining into the environment. One study looking at two decades-worth of bird collisions in Chicago found that reducing light leaking out of windows by just half could reduce bird collisions by 60 percent.
Every year, light pollution increases—by as much as 10 percent, according to one study.
While individual changes to home lights can help local wildlife, communities working together can have the biggest impact.
“Lighting decisions are made by millions of people,” says Kyba. “To make real progress you have to get all those people on board.”
Some communities are showing what those social changes might look like. The entire island country of New Zealand is currently working to meet light pollution standards; and the Pacific island country of Niue was the first country to become a certified International Dark Sky Sanctuary in 2020.
(Read more about New Zealand’s quest to become a “dark sky nation.”)
In 2019, France imposed a new law setting strict limits for how and when light shines at night. In the U.S., the National Audubon Society’s Lights Out program encourages cities from San Francisco to New York to reduce their nighttime lights during periods when migratory birds are passing through. Dimming bright city lights for as little as 30 minutes can prevent fatal bird collisions, according to a 2017 study.
Mar 13, 2020 · Lighting disrupts photosynthesis and the activities of insects, birds and other animals. A recent study, Light pollution is a driver of insect declines, says habitat loss, pesticide use, invasive species and climate change have all played a role in insect declines globally, but that artificial light at night is another important—but often ...
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Jun 20, 2020 · Install lights that are angled down to the area you need to light. Lower the height of your lights so they provide an ambient glow. Use warm coloured lights. Turn your solar LED lights off. Shield ...
