Artificial Lights: Silent but Deadly

In recent years, and especially during quarantine, electronic device usage has seemingly overtaken the world. Indeed, according to The Pew Research Center, smartphone ownership in America has risen from 35% in 2011 to over 81% in 2019, and computer ownership has also skyrocketed. The US Census cites Current Population Surveys (CPS) showing that the percentage of households with a computer has increased from 8% in 1984 to nearly 80% by 2015.  A recent study suggests that the average individual adult living in the United States is now projected to spend over 44 years in front of screens over the course of their lifetime - a number that is likely on the rise as a result of the COVID-19 pandemic. In an age of online classes, social distancing, and working from home, computers are practically unavoidable, but excessive screen time has some serious side effects that should be considered, and there are steps that we can all take in order to mitigate the consequences that we are all facing as we continue to adjust to this new online era. 

LED Lights: A Tradeoff Between Health Risks and Energy Efficiency

LEDs, or light-emitting diodes, are responsible for illuminating many electronics that are currently in use such as computer and phone screens. They are relatively energy efficient because they emit a higher proportion of short wavelength, high energy blue-light-rays when compared to alternative lighting sources (such as incandescent light bulbs), but this excess blue light could prove dangerous by causing shifts in your body’s natural circadian rhythm. Nighttime exposure to blue light causes reduced secretion of a critical hormone called melatonin which is responsible for regulating your body’s circadian rhythms, the natural biological patterns usually dictated by light cycles. Under natural conditions without artificial light interference, melatonin is maximally produced at night and is instrumental in maintaining healthy sleeping habits (and has also been studied as a potential antagonist of the COVID-19 virus. With increased blue light exposure, particularly at night, melatonin secretion is stunted, and circadian rhythms can be seriously disrupted. A study conducted at Harvard University showed that circadian rhythm disruptions could be linked to increased blood glucose levels and higher rates of prediabetes, and a study conducted in Spain found that higher levels of exposure to blue light and subsequent circadian rhythm disruption were correlated with increased rates of breast and prostate cancer.  Researchers at UC Irvine also reported that the circadian rhythm is responsible for regulating up to 15% of a person’s genes and that circadian rhythm disruption could also be linked to increased risk of depression, insomnia, and cardiovascular disease. Clearly, the impact of blue light on circadian rhythms can pose serious threats to human health, and it is imperative that proactive and protective measures be taken.

As blue-light emitting electronics become more ubiquitous in our everyday lives, we must all take care to be proactive and limit exposure to blue light sources by installing blue-light limiting extensions and applications on all electronic devices (Google Chrome has a specific extension called “Dark Mode” which I installed after writing this piece), wearing blue-light filtering glasses, limiting screen time during the nighttime, getting ample, bright natural light during the daytime, and seeking out red-hued lights, especially for nightlights. The increased energy efficiency of LED lights brings heightened health risks, and it is important to ensure that we maintain healthy habits even now, when it can often feel that life revolves around electronic screens.

Artificial Lighting Also Threatens Wildlife

The impact of artificial lights extends far beyond indoor lighting and electronic screens. Humans have transformed natural landscapes, blanketing them with roadside lighting, skylights, traffic lights, neon signs, billboards, intensely illuminated shopping centers and businesses, and much more. Although lighting is a necessity to some extent, it is estimated that at least 30% of all light emitted in the United States is wasted, amounting to over $3 billion dollars spent on unnecessary lighting each year, and levels of lighting and light pollution are on the rise. The artificially illuminated portion of Earth’s surface increases by 2.2% each year, and increasing numbers of artificial lights are in constant use, releasing light rays into surrounding habitats and areas throughout all hours of the night. Artificial lighting has seriously impacted many types of wildlife, from trees to frogs to migratory birds and beyond, and many organisms are suffering as a result. 

Birds

The majority of birds migrate at night, including warblers like the one shown above, and are at risk of being led astray by bright artificial lights, causing them to veer off course and miss out on favorable weather patterns and hospitable conditions.  Artificial lighting can also lead birds to their deaths by luring them toward buildings and windows, often resulting in fatal collisions. Window-strike collisions in the United States are estimated to result in up to 976 million bird fatalities each year, with studies showing that a single high-rise building kills an average of 600-1,000 birds each year. One Texas high-rise was reported to have killed nearly 400 birds in a single night. Other studies have shown that actively dimming the lights within these types of high-rise buildings can lead to an 83% reduction in window strike deaths, serving as compelling evidence for the impact of artificial lighting on bird survivorship. 

Sea Turtles 

Birds are not alone in being led astray by artificial lights. Newly hatched sea turtles are often misguided by bright lights along coastlines, and rather than scrambling toward the ocean, they often move inland, away from the water where they belong. It is believed that baby turtles are naturally drawn toward the moon’s light reflecting off of the ocean, but brightly lit coastal areas often confuse the hatchlings, and the young turtles often perish due to dehydration, predation, or car crashes.   

Coral Reefs

Light pollution is also believed to exacerbate coral bleaching, a devastating phenomenon wherein the mutualism between coral polyps and algae is disrupted, causing the coral to perish. Exposure to artificial lighting is also linked to decreased rates of photosynthesis in corals and increased presence of free radical particles, oxygen atoms with unpaired electrons that are known to wreak havoc within a living organism. Though there is still a lot of research to be done, it is becoming more and more clear that artificial light is having serious consequences on the wellbeing of coral reefs.  

Fish

Artificial light pollution can reach ocean depths of 200 meters or more, disturbing ecological systems in ways that can damage the balance of entire aquatic communities.  In scientific studies, fish exposed to artificial light also tended to swim more out in the open, drawn toward the light, a behavior that puts them at greater risk of predation. In a different experiment, clownfish eggs incubated in persistent artificial light failed to hatch, showing that fish can be extremely vulnerable to the damaging effects of artificial lighting in unexpected and deeply troubling ways. 

Frogs

Light pollution has also been shown to greatly impact the survivorship and wellbeing of frog offspring. One study noted that offspring of adults exposed to excess light pollution were less likely to survive and were more susceptible to parasites as well as other forms of pollution, such as road salt, which is known to cause disrupted sex ratios in subsequent generations and reduce numbers of female frogs over time.  Other research has also demonstrated that exposure to intense nighttime light can reduce mating calls and reproductive activity for some frog species. Recently, amphibian numbers have been falling dramatically, declining by 3.7 % each year in the US alone, with over 70% of the world’s amphibian species currently facing population decline. There are a number of contributing factors to this global amphibian decline, but light pollution is almost certainly playing a role. 

Insects

Artificial light is also known to cause massive disruptions in insect movements and lifestyles. Foraging and mating patterns can be seriously altered as a result of artificial lighting, with some insects drawn toward artificial lights and others repelled by it. Insect reproduction can also be seriously hindered by the presence of artificial light, with some insects like mayflies being drawn to lights, believing them to represent light reflecting off of water, and laying eggs on surfaces unsuitable for offspring survival.  Insects are also attracted to car headlights, and are often killed by moving cars. One study estimates that each summer, over 100 billion insects are killed on German highways alone.  Insect populations worldwide are declining rapidly, with research indicating that current numbers of insects are just 50% of what they were in 1970, and at least 41% of known insect species are on the decline.  Insects, so often overlooked, are the most diverse group of living creatures on the planet and they play essential roles in ecosystems worldwide. That such an important group of organisms are so radically impacted by light pollution is a testament to the importance of actively mitigating the consequences of artificial light for the survival of future generations of all species. 

Plants

Plants too are influenced by artificial lighting, in ways that have cascading effects on other species as well. A study showed that trees exposed to excessive light pollution have also been shown to flower an average of a week earlier than their non-exposed counterparts, greatly upsetting the balance of ecological interactions between the trees and the other organisms, such as pollinating insects, that rely on them. Flowering too early can put many different plants at risk of exposure to unfavorably cold weather conditions or could result in the plant blooming out of sync with its standard pollinators, all of which can ultimately limit the tree’s ability to reproduce. The effects of light pollution are widespread and not yet widely or thoroughly studied, but for plants and other living organisms, the consequences they are enduring are serious and potentially catastrophic. The nice thing about light pollution is that, unlike other forms of pollution, there are relatively simple measures that can be taken to alleviate many of the hazards. There are no pollutants left to clean up, and we only need to turn the lights off in order to fix many of the problems. 

Artificial lighting is everywhere, and it is a part of our everyday lives, but it has serious effects on both human health and on the wellbeing of wild species everywhere. It is critical that humans consider and actively work to mitigate the consequences of artificial light, both at home and in natural environments worldwide. As can be said of anything relating to the natural world, everything is connected, and lighting does not exist in a vacuum. Though humans use and need artificial lighting in a variety of ways, it is having dramatic unforeseen and unintended consequences. Nature is paying the price for our actions, and immediate change is necessary in order to protect the biodiversity that remains.