Blinding Lights
Light is everywhere, almost to an excessive degree. There have been findings that light pollution can have a multitude of impacts beyond erasing the stars.
Bustling cities are great feats of engineering, with their bright high-rise towers and glittering lights, illuminating far and wide. But while streets remain brightly lit, other important things are swallowed up. An estimated 80% of the world population is unable to see the complete night sky as a result of excess artificial light, often referred to as light pollution. (Falchi, 2020) Beyond making the stars invisible, excessive lighting has been linked to highly concerning issues such as worsening human health and causing wildlife death. While the issue is being taken more seriously than many decades ago, there is an immense amount of work that needs to be done to mitigate the effects.
How does light become pollution?
When light is projected into the sky directly or reflected off of any surface, it is scattered in the atmosphere and projected back towards the ground. This creates a diffuse luminance or glow in the sky, a phenomenon referred to as skyglow when caused by man-made light sources rather than natural sources such as the moon or stars. (RPI, 2007) Light can be scattered by gas molecules or particulates in the air, which is why skyglow can be even worse for industrialized cities with plenty of emissions or areas affected by fire smoke.
Light pollution also includes immediate and direct disturbances, such as unwanted light shining on property or causing distractions to birds. (Drake, 2019) As cities have grown exponentially, the amount of artificial light has increased as well, often resulting in poorly designed fixtures that over-illuminate areas and unnecessarily emit light upwards. Many believe that bright lighting is necessary for creating safer streets, but in fact, there is no evidence that increased street lighting reduces reported crime. (Riggs, 2014)
With the introduction of short-wavelength LEDs, lighting became more efficient and cheap. LEDs are everywhere now from highway street lamps to digital billboards. Unfortunately, these shorter wavelengths of light create problems. In the visible color spectrum, shorter wavelengths include blue and purple, which is why many of the modern white LED fixtures appear bluer compared to the yellow hue of incandescent light bulbs. Unfortunately, atmospheric scattering is greater for these short wavelengths, resulting in increased skyglow. (Gaston, 2012) Many biological processes are also highly sensitive to blue light, so a higher concentration of short-wavelength light emitted by modern light sources has caused clear harm to many species including humans.
Effects on Human Health
Excessive light can affect our sleeping habits and how our bodies recover at night. Melatonin, the hormone most responsible for sleep, is directly affected by light and is triggered around sunset, peaking at midnight. (Drake, 2019) Any light emitted from a screen or streetlight shining through the window can deter the natural melatonin process and disrupt the body’s circadian rhythm. Decreased melatonin levels have been linked to adverse health effects such as heart disease, obesity, and even cancer. On top of a stressful life, these further issues can all compound.
Ecological Damage
At night, birds can become disoriented from artificial light or glare, causing them to collide with buildings and fall to their death. It is especially lethal during migration periods. Excess light is estimated to kill millions of migrating birds every year across North America. (Drake, 2019) Flightless animals as well as species located further away from urban areas have been found to be affected, such as plants, insects, and marine animals.
Sea turtles use moonlight shining off of the water as one of their navigation cues to find the ocean. (Drake, 2019) Similar to birds, urban lighting near the shore can confuse turtles. They end up getting lost and dehydrated, becoming a target for predators. Light pollution is claimed to be one of the highest sources of early death for sea turtles, according to the Sea Turtle Conservatory based in Florida. Greater knowledge of the damage caused by excess light has influenced development policies. In Florida, efforts to introduce wildlife-friendly lighting to coastal homes have dramatically reduced disorientation and thus improved survival rates.
Raising Awareness
It is believed that awareness of the negative effects began as early as the late 19th century, although widespread efforts to reduce light pollution didn’t begin until much later. The dark sky movement began in the 1980s, started by the International Dark-Sky Association. There are now many groups similarly motivated to preserve astronomical observations and bring awareness to the devastating impacts of light pollution. Some of the main recommendations to individual homeowners include the steps: directing light towards the ground, using motion detection or timers to limit their use only when necessary, and replacing harsh short-wavelength LED lights with longer-wavelength LEDs. (Gaston, 2012)
Preserving Darkness
Of course, the burden shouldn’t be carried by individuals, and city lighting planners have also begun to take responsibility by incorporating similar methods. For example, the Canadian town Jasper is working with Lumican to replace their harsh street lighting with a newer type of LED with controlled wavelengths that would cast a more amber glow. (Drake, 2019)
Another method that goes a step further is establishing dark sky preserves or dark sky areas (DSAs). (Silver, 2020) Ideally, these are areas that regulate light pollution to improve scientific and tourist observation, ecological conservation, and preserving heritage. DSAs have already been established in areas such as national parks and rural communities. However, many complications arise from the controversy of regulating light.
Even in small towns where the local population supports improved lighting regulation, there will always be difficulties making rules that work for everyone. In a report by Silver and Hickey, some conflict was observed during the implementation of dark-sky regulations in the town of Gravenhurst. While some Gravenhurst officials and business owners believed that dark-sky bylaws were overregulation, activists argued that the bylaws weren’t doing enough to lower light pollution levels. Still, the authors of this report believe that DSAs are more feasible in rural towns that benefit from ecotourism. Since these towns aren’t as dense, they take a lower amount of resources to invest in, creating a lower hurdle for urban planning. On the flip side, DSAs are less likely to be accepted in densely populated areas where the benefits aren’t seen as worthwhile. To overcome sociopolitical barriers to light regulation, more awareness of the adverse effects of light pollution is needed to influence swifter and more drastic changes.
There is compelling evidence that our current inefficient lighting methods are not working. The wider availability of cheap lighting options and the need to illuminate every corner of cities has generated a society too comfortable with blinding lights. Harsh glare from street lamps, digital billboards using short-wavelength LEDs, and individual houses, have all been shown to have negative effects on many different walks of life. Fortunately, solutions are readily available. Simple lighting changes and advancements in long-wavelength lighting have shown promising results. While they may be an initial investment, they will greatly benefit cities and the environment in the long run.
Sources:
Falchi, F., Cinzano, P., Duriscoe, D., Kyba, C. C. M., Elvidge, C. D., Baugh, K., Portnov, B. A., Rybnikova, N. A., & Furgoni, R. (2016). The new world atlas of artificial night sky brightness. Science Advances, 2(6). https://doi.org/10.1126/sciadv.1600377
Rensselaer Polytechnic Institute. (2007, February). What is sky glow? NLPIP. https://www.lrc.rpi.edu/programs/nlpip/lightinganswers/lightpollution/skyglow.asp
Drake, N. (2021, May 3). Light pollution is getting worse, and Earth is paying the price. National Geographic. https://www.nationalgeographic.com/science/article/nights-are-getting-brighter-earth-paying-the-price-light-pollution-dark-skies
Riggs, M. (2014, December 2). Street Lights and Crime: A Seemingly Endless Debate. Bloomberg. https://www.bloomberg.com/news/articles/2014-02-12/street-lights-and-crime-a-seemingly-endless-debate
Gaston, K. J., Davies, T. W., Bennie, J., & Hopkins, J. (2012). REVIEW: Reducing the ecological consequences of night-time light pollution: options and developments. Journal of Applied Ecology, 49(6), 1256–1266. https://doi.org/10.1111/j.1365-2664.2012.02212.x
Silver, D. A., & Hickey, G. M. (2020). Managing light pollution through dark sky areas: learning from the world’s first dark sky preserve. Journal of Environmental Planning and Management, 63(14), 2627–2645. https://doi.org/10.1080/09640568.2020.1742675
