Carpe noctem: Notes on The Darkness Manifesto by Johan Eklöf

"Henceforth if you want me after sunset you will only find me by candlelight." ★5

Feb 23, 2025

At barely 200 pages with short chapters, The Darkness Manifesto is a quick read with a powerful message—and one of my new favorite books. Eklöf’s reflections on light pollution have officially made my “recommend to everyone” list. (Especially people who have disagreed with me about daylight saving versus standard time… hey hey, the dark isn’t always so bad! 😉)

Of course, I was predisposed to like this book because I agreed with the argument going in. Living in a van has pushed me further in the direction of “crunchy environmentalist”, and I’ve experienced firsthand the joys of a truly dark night: staring at the Milky Way in Utah’s desert, catching falling stars with Sean in the Badlands, spotting bats with our naked eyes around the country. I’ve even grown unsettled (in a cool way) beneath Alaska’s midnight sun where it never really got dark at all. These moments have cemented in me a deeper love for the natural rhythms of our world.

But even if I didn’t already appreciate those things, I like to think Eklöf would have convinced me. He is gentle in his communication. His love for creatures, for the natural world, for the wonder of experiences beyond typical human focus, seems obvious. I told Sean parts of the book read as almost tender (and that’s even through a language translation).

My favorite Goodreads review of The Darkness Manifesto is simple: “Henceforth if you want me after sunset you will only find me by candlelight.”

Things I loved in this book

Some surface-level fun

He mentions Thomas Nagel, of course (who is the reason I have a little bat tattoo on my arm!)
He knew Donald Griffin personally
He references The Hitchhiker’s Guide to the Galaxy

Deeper joys

Eklöf acknowledges that it’s natural for us humans to want to light up the night—he isn’t preachy or self-righteous—but offers plenty of scientific evidence and emotional resonance for us to try getting comfortable with darkness
So. Many. Cool. Creature. Stories. Mammals, birds, deep sea animals…
Many references to other books and research; my TBR has grown as a result
Eklöf inspired me to think of things I simply never had before—like that the day/night cycle has been the most constant variable on our planet through so many other climate and geographical changes, and that lighting up a sliver of darkness really serves to make anything outside that beam even harder to see

Things we’re changing as a result of this book

Since moving into Hermes—and, admittedly, first being exposed to some of the effects of artificial light on humans years ago via The Huberman Lab podcast (one I rarely listen to anymore)—Sean and I have been inching our way towards nighttime harmony. The Darkness Manifesto inspired us to take further changes more seriously.

Once the sun sets, we’re using as little light as physically possible. I used to love plugging in my “cozy lights” (a strand of black string lights in our bed) when it got dark—my middle-ground solution is to turn them on just before sunset and shut them off around nautical twilight.
If we do need to have brighter light on after dark, we’re making sure our window covers are up so we aren’t disrupting insects, birds, or mammals outside the van.
We’re keeping our computer brightness and warmth at the bare minimum in the evening. Same with our Kindle backlights.
When venturing out of the van at night, we’re avoiding flashlights unless truly necessary for safety (like if we’re walking along a road and need cars to see us).
No more bedtime snacks, unless I really messed up my eating schedule during the day and know I’ll wake up hungry.
More stargazing!!

Highlighted passages

My top favorite quotes

(Bolded emphasis my own.)

Page 16: The loss of the experience of night can possibly seem nostalgic and tangential. But there’s a lot of research showing that the human being in the Anthropocene experiences strongly negative effects from too much artificial light. The light disturbs our biological clock, causing sleeping difficulties, depression, and obesity.
Page 30: Much more research has been done on how to kill insects than on how to save them, which is fairly telling about how we humans operate.
Page 33: The more the attention on the impact of ecological systems and our own wellbeing, the closer we’ll get to reconciling society’s need for light with nature’s need for darkness.
Page 212: Many of the animals that live under the protection of darkness are on the verge of extinction and with them their invaluable services—pollination and pest hunting. And we humans have ever-worsening sleep and plants are aging prematurely when the night is absent.
Page 210: Light pollution is the easiest of all environmental problems to solve, at least technically.

Setting the book’s purpose

Page XI: Half of the insects on this planet are nocturnal, and for the last couple of years we have been drowning in alarming reports regarding their disappearance. Forestry, environmental toxins, large-scale farming, and climate change—many causes are mentioned but little is said about light, even though the light-sensitive moth is one of those most disappearing.
Page XII: It is no longer just a question of stars and insects. It is about all living things, including we humans. Ever since the birth of our planet, day has been followed by night, and every cell in every living organism has built-in machinery working in harmony with that rhythm. The natural light calibrates our inner circadian rhythm and controls hormones and bodily processes.
Page XIII: I hope that this book will inspire others, function as a reminder of the importance of letting the night be a part of our lives, and give insight into how much damage artificial light can do—be a challenge and a manifesto for the natural darkness.

On why darkness has been important… forever

Page 3: Through billions of years—Earth is 4.5 billion years old—our planet has changed form, slowly or in sudden events. … But one thing has remained more or less constant: the alternation between day and night, between light and darkness. The sun has always gone down in the west and risen again in the east, and in between those moments it has been night.
Page 5: The biological clock, our circadian rhythm, is ancient, shared, and completely fundamental. Everything living today has developed in a world where the conditions are changed over the day and over the year.
Page 6: It’s light and darkness that calibrate the biological clock. … The artificial light from lamps, headlights, and floodlights is not in this equation and risks, to put it mildly, creating disorder in the system.
Page 58: Life has evolved in accordance with the day’s alternating light and darkness, and the more animals we study, the more we realize that both day and night are equally important for their ecology.
Page 110: The more you look, the more marine organisms you’ll find that rely on signals from the lunar cycle, often in combination with other clues such as sunlight levels or water temperature.

On humans chasing out darkness

Page 13: We humans are in many ways completely dependent on visual sensory impressions, so therefore light means safety for us. So it isn’t strange that we tend to want to light up our existence.
Page 14: Human beings have extended their day while forcing out the night’s inhabitants.
Page 14: Despite the much good that technological developments have done for humans—with their concrete as well as symbolic illuminations—in their tracks plainly follow energy wastefulness, rampant consumerism, and ecological degradation.
Page 62: light without a shade radiates more light and energy into the atmosphere than down to the walkway it was intended to illuminate.
Page 98: Artificial light isn’t only one of mankind’s most amazing inventions, but can also without a doubt be detrimental to life itself. It can mislead 200 million years of instinct in an instant.
Page 142: The king’s light installations were a demonstration of power, and lighting is used in a similar way to this day. The previously mentioned giant spotlight, the Luxor Sky Beam in Las Vegas, is a clear example of that.
Page 168: [August] Strindberg was partially correct that lighting was political. It was a way to increase efficiency, but also a demonstration of strength, in the same way as were the striking installations and the presentations of candles in the eighteenth century. The light could project an image of wealth and power.
Page 187: One single light or spotlight in a block causes the eye to adjust to that level of illumination. … The surroundings around the strong light turn black, and we experience a deeper darkness than we would have without the strong light. That means one single bright point can completely trick the eye.
Page 191: For security we increasingly illuminate things, but the illumination makes us dazzled and blind and—it may well be argued—less secure rather than more.
Page 192: The phrase less is more was coined by Ludwig Mies van der Rohe (1186-1969), referring to clean forms in architecture, but could just as easily refer to lighting. Well-balanced lighting makes it easier for the eye to focus in the twilight.

On how light pollution affects other animals and plants

Page 9: As humans—with our senses’ limitations—though we know about these animals’ visual faculties, we can never understand the real experience. Filters in cameras or visual enhancement through other machines let us have an inkling, but we can never completely see with the eyes of insects or cats.
Page 10: No less than a third of all vertebrates and almost two-thirds of all invertebrates are nocturnal, and so most of nature’s activity—mating, hunting, decomposing, and pollinating—occurs after we humans fall asleep at night.
Page 82: As skyscrapers have grown high on the America contingent, the problem of light-confused birds has only increased.
Page 82: Given how the world’s big cities are expanding and spreading their light farther and farther into the countryside, and higher up in the atmosphere, nights are increasingly rarely starry enough and suitable for navigation.
Page 90: Global warming and artificial light reset the internal clocks of plants, risking destroying the delicate balance between plant and pollinator, between plant and herbivore, between prey and predators. If the temperature rises just a few degrees or twilight is shifted only by a few moments, the timing between flowering and the creatures who take advantage of that flowering can be disrupted. [Made me think of Thor Hansen’s Hurricane Lizards and Plastic Squid book too]

On how artificial light impacts humans

Page XII: Beneath the illuminated sky in the lit-up cities we have created, we can no longer see any stars, and many of us don’t remember what the Milky Way looks like. We are missing out on one of nature’s grand treasures.
Page 130: We experience a cycle of light that is alternately dominated by blue and red depending on whether it’s morning, noon, or evening.
Page 151: Today we’re uncovering more and more of the secrets of the universe, and it’s now been more than fifty years since humanity took its first small steps on the surface of the moon and with them the giant step into the space age. Yet at the same time more and more astronomical experiences and phenomena are being wiped out for ordinary people.
Page 171: As soon as our retinas are hit by the morning’s sun, photon swarms signal the nerves to the suprachiasmatic nucleus—the node of the brain for the circadian rhythm.
Page 171: Humans, just like other animals and plants, react differently to different types of light. The blue light means it’s day, the red means it’s evening. … more than anything else the bluish daylight resets our internal clock, through the cryptochromes, the light-sensitive proteins, and indicates that the day can begin again.
Page 172: Among fifteen- to twenty-nine-year-olds, more than 80 percent have their phones with them in bed. The last thing we do in the evening is set an alarm, check social media, read emails, or just scroll. Before that we might have spent a couple of hours in front of the TV or the computer, followed by a few minutes in a bright white-tiled bathroom. Maybe we had an evening snack because the leptin, the hormone that makes us feel full, hadn’t yet kicked in. … No matter what light we expose ourselves to in the evening, we’re disturbing the natural wave of melatonin, which is meant to wash over us at dusk, eventually ebbing out in time for the morning. The worst is blue light, what is most similar to daylight, but other light affects us, too.
Page 174: We may not be able to cure or prevent depression all at once by cutting down on electric lighting, but we definitely increase the chances of a good sleep in the long run.
Page 176: We still don’t know everything about how light affects us humans and the extent to which a disturbed sleep cycle causes different kinds of health issues. But night-shift workers are clearly more at risk than other people.
Page 205: When we are dazzled by a light, it turns of four entire peripheral field of view, and darkness creeps in on us from all sides. A row of lanterns along a walkway ensures that we see where we are going, but outside that space lurks a dense nothingness. … security and darkness can be experienced together.