As light pollution engulfs over 80 percent of the world's skies, artificial light has demonstrated its detrimental impacts on the health of humans, ecosystems and the planet.

Artificial lighting fixtures like street lights and billboards have become commonplace for billions across the globe. While artificial light has been in use for centuries, light pollution has dramatically increased over the past few decades. Considering the global urban population is projected to rise by up to 68 percent in the next 25 years, the demand for artificial light is unlikely to subside.

Light is integral to life on Earth, influencing the planet's creatures down to their DNA. From reproduction to protection from predators, many life-sustaining behaviors rely on the cycle of day and night. Artificial light has been shown to disrupt life in many kinds of ecosystems. In the wetlands, artificial light interferes with nocturnal mating rituals. Starlight and the Sun's rays also serve as important navigation devices for many animals and insects. When artificial light disrupts these natural signals animals like baby sea turtles and birds can be drawn to their demise.

Within ecosystems, seemingly small changes brought by the presence of artificial light can have cascading effects. For example, some predators have evolved to target insects swarming artificial light. As vital members of the food chain, the decline of insect populations poses a threat to everything in the food web.

The reach of artificial light is not limited to urban areas, as it has been found to seep below the soil and into the oceans. Artificial light hinders the ability of microorganisms in the dirt to use carbon. Meanwhile, artificial light in the oceans has been found at depths of more than 66 feet, affecting the life-sustaining activities of many marine species.

The negative effects of artificial light are not always direct. The electricity required to sustain the current consumption of artificial light mostly comes from coal-fueled power plants. This production emits 15 million tons of carbon dioxide into the atmosphere every year, contributing to climate change and posing further threats to ecosystems.

People are not immune to the negative effects of their own creations. A mere 15 minutes of exposure to bright artificial light has the power to halt melatonin production. Due to its disruptive effects on circadian rhythms, artificial light can contribute to health conditions ranging from sleep disorders to heart disease. While artificial light is often used as a tool for safety and security, it can have the opposite effect. For example, glaring light can cause poor visibility.

While artificial light may be necessary for people to function at night, nearly one-third of all lighting is unnecessary, leaving ample room to cut down on its negative effects. Scholars propose prioritizing dark sky conservation in electric lighting design, using warm-colored light, and avoiding blue-colored light. Blue-colored light is particularly harmful for people and ecosystems alike because it scatters farther than warm-colored light. People can limit their light pollution by shielding, dimming, and turning off lights. Advocacy organizations suggest keeping light pollution in mind when shopping for lighting products. Environmentally friendly models will have adequate shielding to prevent glare and limit the amount of light escaping into surrounding areas. 

TO GET INVOLVED

To advocate for limiting light pollution, get involved in non-profits like DarkSky and Light Justice, which offer opportunities for advocacy and education.

Madison is a student at George Washington University studying international affairs, journalism, mass communication, and Arabic. Born and raised in Seattle, Washington, Madison grew up in a creative, open-minded environment. With passions for human rights and social justice, Madison uses her writing skills to educate and advocate. In the future, Madison hopes to pursue a career in science communication or travel journalism.