Zoologist Johan Eklöf began to consider the disappearance of darkness in our bright world in 2015, when he was counting bats in southern Sweden.
The surrounding grounds were dark, as they had been decades before when his academic adviser had counted the bat populations in the region's churches;
however, in the years since, those churches (whose steeples are prized by winged mammals) had been illuminated by spotlights.
“I started thinking: how do bats react to this?”
, explained Eklöf.
The short answer is: not very well.
Together with his adviser, Jens Rydell, Eklöf launched a new bat census and discovered that in 30 years (the average lifespan of a bat) half of the colonies in the area had disappeared.
Zoologist Johan Eklöf in Ulricehamn, Sweden.
(Nora Loreck/The New York Times)
That research led Eklöf to study how artificial lighting affected other species, including those responsible for installing floodlights in churchyards.
The book that stemmed from that research, "The Darkness Manifesto," published by Scribner on February 14, is a sweeping exploration of humanity's troubled relationship with the dark and the detrimental effects of our eager to fight it.
Astronomers began using the term
“light pollution”
in the 1960s, and today it mainly refers to the persistent glow emanating from cities at dusk, blocking out the stars and turning the night sky an orange-grey. .
In 2016, 80 percent of the world's population (and 99 percent of the population in the United States and Europe) lived under light-polluted skies.
A study published this year in the journal Science revealed that between 2011 and 2022,
light pollution on Earth increased by 9.6 percent per year
.
“It really shook my faith,” Christopher Kyba, a researcher at the German Research Center for Geosciences and lead author of the study, said of the dramatic results.
"I had been quite optimistic and believed that with new technologies things would improve, because the lights are better designed, but instead we see that most countries are getting brighter."
Currently,
a third of the world's population cannot see the Milky Way
, even on the clearest nights, but the impact of all that light goes far beyond preventing stargazing.
As “The Darkness Manifesto” explains in fascinating, if terrifying, detail, all living organisms are governed by light-sensitive circadian rhythms that, if disrupted, can trigger effects ranging from an impaired sense of orientation (poor dung beetle that, unable to see the stars that help it move, cannot take its nutritious ball of dung home with it)
to mass executions
(As happened to the swarm of grasshoppers that, attracted by the lightning fired by the Luxor casino, descended on Las Vegas in 2019 and ended up like all the inert confetti that crowds the Las Vegas Strip).
As anyone who has ever watched moths endlessly circle their porch light can attest, artificial bulbs can be deadly to insects.
“Many die before dawn, sometimes from sheer exhaustion,” Eklöf wrote.
Even those that survive “have not reached their nightly targets.
They have not obtained their nectar (and transported the pollen of the plants), they have not found a mate and they have not laid eggs”.
But this does not only affect insects.
Newly hatched sea turtles head inland toward the glow of the city, rather than the moonlit sea.
Fooled by outdoor lighting, urban trees stay green longer than their rural counterparts.
On one Australian island, the light was so disturbing that the wallabies, whose gestation is usually triggered by the summer solstice, ended up calving so late that they ran out of food.
Even coral, which in Australia normally reproduces once a year when the December full moon prompts it to release a "blizzard" of male and female sex cells, is getting confused;
disoriented by artificial light, the release of gametes is no longer synchronized, which decreases reproduction and contributes,
When Eklöf, who also runs a consultancy that includes advising companies and governments on how to minimize their light pollution footprint, began research for The Darkness Manifesto, the various impacts of light pollution had not yet been thoroughly studied.
The book was published in Sweden in 2020, and in the last two years the topic has exploded, she explained.
"And with each species studied, light is found to have certain effects," he said.
“Also, they are all interrelated, so it threatens the entire system.”
That system includes us.
“
The Darkness Manifesto” records how light pollution has increased insomnia, depression and even obesity
: leptin, the hormone that controls appetite, works in tandem with melatonin, the light-sensitive hormone that induces sleep , but Eklöf is also interested in the repercussions that are not strictly related to health.
“Losing the connection with the night sky and the stars is losing our connection with nature, but it is also losing our history,” he said.
"The night sky has been the same for billions of years and what we see now is the same sky that our ancestors looked at and made stories about."
Many of those stories were about the terrors of the dark in humans, who, unlike about two-thirds of mammals, are not nocturnal.
Fear continues to motivate us to dispel the darkness
, even though we are, for the most part, far removed from the demons and monsters that haunted the nights of our predecessors.
“People often say that they need light to feel safer,” Eklöf said, “even though all these studies show that crime has nothing to do with a light or dark city.”
“If there are no people in the park, there is no need to light it,” he said.
Motion sensors, timers, and red or yellow spotlights, whose light mimics stars at night more than bright white light, can also help.
Measures are already being taken in some places.
France has adopted a national policy that imposes curfews on outdoor lighting
and drastically limits the amount of light that can be projected into the sky.
Flagstaff, Arizona regulates the direction of exterior light beams and limits the number of lights in a given location.
Around the world, some countries, especially those with regions less polluted by city lights, are embracing “dark sky tourism”, which encompasses activities such as stargazing tours or excursions to see the Northern Lights.
FILE - The Milky Way in the night sky over Arches National Park in Utah.
(John Burcham/The New York Times)
With dark-sky parks and even a dark-sky festival in County Mayo
, Ireland is taking the lead in dark-sky tourism.
Eklöf hopes that his book, which culminates in a true manifesto, will inspire readers to accept the darkness of night more fully.
Part of her research focuses on the sighting of bats (which, it should be noted, are not really blind).
That job has led him to spend many nights outdoors.
“I like the dark and looking for bats at twilight,” he said.
"It's kind of relaxing."
Relaxing and, at times, exciting.
The other night, Eklöf took her teenage daughter out to watch a comet fly through the skies.
"He's 14 years old, so he's not interested in anything," he said with a laugh.
“But that was fascinating to him.
There's something about being small under the night sky that fascinates us all."
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