Forgotten centuries ago, the inhabitants of the blue planet Gaea evolved to become biologically dependent on daily cycles of light and darkness. Human descendants of hominids created communities and then cities to house their growing population, and increasing density was accompanied by socialization and community activities well into the night. Wayfinding and security at night from marauders and thieves became concerns for the species, and there was a hue and cry to provide anthropogenic light. Gaeans learned to burn candles and oil in lanterns, the warm glow into the night of lanterns lighting the way and keeping citizens safe from mischief.
Centuries passed and then electricity was discovered and tamed. A lamp using electricity was invented and electric lights were quickly adopted throughout the cities and towns. Electricity company owners seized the opportunity to distribute and promote increasingly profitable electric lights and to operate them all night. Society evolved with it and extended socialization and business hours through the night as people lost their innate fear of the shadows of night. Over less than a century, the night became significantly less dark, and, in many places, there was little difference anymore between day and night. Like many other human inventions, anthropogenic light at night (ALAN) became virtually out of control and quickly began to disrupt the cyclic photoperiods and symbiotic existence of humans, insects, fish, avians, amphibians, mammals, trees, algae, and all other life forms. Mostly ignoring ALAN, the humans debated many other pollutants, climate change and loss of habitat while many species moved towards extinction and the blue planet turned brown.
Concern for the impacts of ALAN were largely ignored until 1987 when the International Dark Association (IDA) was formed in Arizona. Other nascent efforts to address ALAN included the Fatal Light Awareness Program (FLAP), begun in 1993 in Toronto to combat bird deaths due to lights in high rise buildings1. And in a stunning reversal of past practices, the IES Environmental Lighting Committee created and published Recommended Practice for Lighting for Exterior Environments RP-33 in 1999, for the first time introducing the lighting industry to the impacts of anthropogenic light at night (ALAN) and explaining principles to mitigate light pollution. The idea that light could be considered pollution was a warning siren to an industry accustomed to always increasing the uses and amounts of outdoor lighting with little or no regard for its negative impacts. It was not taken very seriously at the time.
Another warning siren came soon after from the environmental science community. In 2002, the American researchers Dr. Travis Longcore and Catherine Rich organized the first conference on the ecological consequences of artificial light at night. “That meeting, and a research textbook that Longcore and Rich published afterward2 , are widely considered the genesis of interest in the environmental-science community.”3 What inspired these environmental scientists was a scheme to light a prominent bridge in Los Angeles with millions of lumens of narrow beam metal halide lighting shooting straight up in a column of light. That installation was ultimately stopped by the Los Angeles environmental community, but shortly afterward a similar system was installed at the site of the World Trade Center in New York. As predicted by Longcore and Rich, the Towers of Light attracted migratory birds that flew in circles upward until falling to their death from exhaustion. The deadly outcome has caused use of the lighting to be very restricted, but still, the Tribute in Light has been blamed for affecting over 1.1 million birds over 7 years despite being limited to operation for one night per year.4
In 2011, an IDA team consulted with the Florida Fish and Wildlife Conservation Commission that led to a report5 strongly recommending the immediate use of the “Best Available Technology (BAT) to reduce light pollution on beaches …needed to preserve sea turtles as a species.” Being left with a choice of action or sea turtle extinction, the right choice was made and today there is enforcement of restrictions against ordinary lighting on Florida beaches. But it raises the question why we seem to always move rapidly and carelessly towards the making them vulnerable to predators. Light pollution from the iconic Sundial Bridge was a factor that contributed to the near loss of Sacramento River fall-run Chinook salmon from 2011–2013.6” We should have known better.
Today the blue but browning and struggling Gaea is subjected to many forms of pollutants in addition to the loss of darkness at night. Worldwide climate change dominates the headlines while increasing darkness-denied circadian impacts to all living beings are but a few of the imminent challenges the planet’s inhabitants face. In recent years we fiercely debate the correct color temperature for outdoor lighting yet continue to encourage the burgeoning trend of color changing, vibrant outdoor lighting for everything from casinos to airports and bridges and attach multiple story video screens to buildings and billboards. We have proven with energy efficiency that as a lighting industry we can precipice before coming to terms with the impacts of our work on life itself.
A celebrated and prominent bridge spamming the salmon run of the Sacramento River, the Sundial Bridge designed by Santiago Calatrava in Redding, California is a masterpiece. Completed in 2004, It connects campuses of major city park across the Sacramento River. As usual, the lighting of this bridge was designed for human activities without regard for surrounding life forms and especially the life cycle of salmon, a major economic contributor to the entire region. Bridges, in particular, often have lighting that shines into rivers at night, and attraction to these stationary lights can stop juvenile fish in their tracks as they migrate downstream, respond to the challenges of our Gaea’s future, but we must now undertake work with equal haste to put the darkness back into the night, not just for humans but all life. Gaea’s revenge has started and of course not just because of our loss of night – but reviving the night is something we can do before Gaea has had enough of us.
“The last word in ignorance is the man who says of an animal or plant: ‘What good is it?’… If the biota, in the course of aeons, has built something we like but do not understand, then who but a fool would discard seemingly useless parts? To keep every cog and wheel is the first precaution of intelligent tinkering.” Aldo Leopold
1 Bright Lights, Big City, Dead Birds, FLAP 2000
2 Ecological Consequences of Artificial Night Lighting, Travis Longcore and Catherine Rich, 2002
3 Rebecca Boyle, The Atlantic, September 2019