It is at best hubris and at worst obscene to think that we can even answer the question; to think that we could even crudely predict the consequences of such a monumental change in our lived experience. But in reality there is no prediction to be made because most humans now live in cities where the night sky has been blotted out. We do not need to predict the consequences rather we need to determine what we have lost. It is a relatively new experience for humanity to be living without stars and consequences are only now coming to light.
The New York Times Magazine recently featured a slide show of images by photographer Thierry Cohen that show cityscapes and the (normally absent) starry sky. Cohen’s project is titled “Darkened Cities” and it re-inserts what has been lost so that we can better know and feel what has been taken from us. The sky in Cohen’s photographs is brilliant and it is not a product of his imagination, it is the genuine sky of the world we live in, he has just photographed it in places where it remains visible and inserted into a cityscape where it is generally hidden from view.
The project highlights the fact that we are born into a denuded landscape (skyscape?) and so often only notice the loss that happens during our relatively short lives. We don’t frequently question the desecration that occurred prior to our own individual existence. But obviously we suffer from decisions made prior to our birth just as our decisions today will either benefit or harm those who follow us. That we are not always aware of the harm that has been done does not lessen—in fact it may amplify—our loss.
At some point—or more accurately, at a great number of points—a decision, or more accurately a long series of decisions, was made that stars are not important to our well being. That we can blot out the night sky without suffering…or at least not suffering in a way that couldn’t be offset by some perceived benefit. But what benefit could be sufficient? And how can such a decision be made and imposed on the whole community of life?
In a 2004 article in Frontiers in Ecology and the Environment, Travis Longcore and Catherine Rich distinguished between “astronomical light pollution” and “ecological light pollution”. The former is light pollution that obscures our view of the night sky; the later is light pollution that disrupts the normal light-dark patterns that are part of the ecosystems that animals—human and nonhuman—have evolved in concert with.
The human health effects are significant and are still being documented.
In 2012, the American Medical Association issued a report on the health effects of light pollution stating:
“The natural 24-hour cycle of light and dark helps maintain precise alignment of circadian biological rhythms, the general activation of the central nervous system and various biological and cellular processes, and entrainment of melatonin release from the pineal gland. Pervasive use of nighttime lighting disrupts these endogenous processes and creates potentially harmful health effects and/or hazardous situations with varying degrees of harm…Even low intensity nighttime light has the capability of suppressing melatonin release. In various laboratory models of cancer, melatonin serves as a circulating anticancer signal and suppresses tumor growth. Limited epidemiological studies support the hypothesis that nighttime lighting and/or repetitive disruption of circadian rhythms increases cancer risk; most attention in this arena has been devoted to breast cancer.”
Ecological Consequences of Artificial Night Lighting—a volume edited by Longcore and Rich—catalogs the deleterious effects on animals. Many animals are disoriented, attracted or repelled to artificial lighting. Migratory birds are drawn off course and crash into illuminated buildings. Nocturnal foragers are faced with what is effectively a “perpetual full moon” and consequently may have reduced time to obtain needed calories or else face greater exposure to predators. Predator-prey relationships and reproductive patterns can be disrupted. Wildlife corridors may be effectively blocked.
Below is a short list of more specific findings from the recent scientific literature:
- Artificial Night Lighting and Sea Turtles (2003)
Sea turtle hatchlings exposed to lights may fail to find the sea after emerging.
“What happens is documented on the beach surface by their flipperprints…Instead of tracks leading directly to the sea, turtles leave evidence that they crawled for hours on circuitous paths (‘disorientation’), or on direct paths away from the ocean and toward lighting (‘misorientation’).”
- Apparent Effects of Light Pollution on Singing Behavior of American Robins (2006)
“Proliferation of artificial nocturnal light may be strongly affecting singing behavior of American Robins at a population level.”
- The Effect of Light Intensity on Sockeye Salmon Fry Migratory Behavior and Predation by Cottids in the Cedar River, Washington (2004)
“increased light intensity appears to slow or stop out-migration of fry, making them more vulnerable to capture by predators such as cottids”
- Studying the Ecological Impacts of Light Pollution on Wildlife: Amphibians as Models (2007)
“Results…demonstrate that artificial night lighting has the potential to affect foraging and breeding as well as growth and development of frogs and salamanders…artificial night lighting should be considered an additional factor that negatively impacts amphib¬ian populations”
- Street Lighting Changes the Composition of Invertebrate Communities (2012)
“invertebrate community composition is affected by proximity to street lighting independently of the time of day. Five major invertebrate groups contributed to compositional differences, resulting in an increase in the number of predatory and scavenging individuals in brightly lit communities. Our results indicate that street lighting changes the environment at higher levels of biological organization than previously recognized, raising the potential that it can alter the structure and function of ecosystems.
- Does Night Lighting Harm Trees (2002)
Artificial lighting “can change flowering patterns, and most importantly, promote continued growth thereby preventing trees from developing dormancy that allows them to survive the rigors of winter weather.” Additionally, disruption of flowering patterns can in turn negatively affect pollinator species.
Even aquatic animals are not exempt from the bright lights of humanity. Fishing boats, offshore oil rigs, and research vessels project light in places and times that would otherwise be dark. In some cases, aquatic animals live and/or feed at very specific depths. A particular depth can normally be assessed by the amount of sunlight that penetrates the water. This is disrupted by artificial light thereby generating conflict and exacerbating competition.
A 2001 article in Monthly Notices of the Royal Astronomical Society calculates that:
“about one-fifth of the World population, more than two-thirds of the United States population and more than one half of the European Union population have already lost naked eye visibility of the Milky Way. Finally, about one-tenth of the World population, more than 40 per cent of the United States population and one-sixth of the European Union population no longer view the heavens with the eye adapted to night vision”
So in exchange for compromised human health, dead animals, damaged ecosystems, and a sky void of stars we have gained the ability to forego sleep by working graveyard shifts under fluorescent lights. If there is such thing as a birthright it must include the full use of our eyes and an unimpeded view of the night sky.
International Dark Sky Association www.darksky.org
Additional research articles about ecological light pollution compiled by Christopher Kyba (Free University of Berlin) http://userpage.fu-berlin.de/~kyba/literature/ecol_light_pol.html