The Luxor Hotel’s “sky beam,” in Las Vegas, generates forty-two billion candlepower of light each night, confusing flying creatures that are drawn to its radiance. Illustration by Carson Ellis

We already linked to one review of it but this book seems worthy of at least two, and if at least one of them is by this essayist then probably two will be enough:

Is Artificial Light Poisoning the Planet?

A Swedish ecologist argues that its ubiquity is wrecking our habitats—and our health.

Among the many looming ecological disasters that terrify us today, one that only a handful of people have contemplated as sufficiently looming and terrifying is the loss of the bats in our belfry. According to “The Darkness Manifesto” (Scribner), by the Swedish ecologist Johan Eklöf, most churches in southwest Sweden had bat colonies back in the nineteen-eighties, and now most of them don’t. Light pollution, his research suggests, has been a major culprit: “District after district has installed modern floodlights to show the architecture it’s proud of, all the while the animals—who have for centuries found safety in the darkness of the church towers and who have for 70 million years made the night their abode—are slowly but surely vanishing from these places.”

The presence of bats in the belfry, as a metaphor for disordered thinking, is usually taken to refer to the way bats would flutter around the upper stories of distressed churches, but a larger madness, Eklöf thinks, is responsible for their absence. A professor at Stockholm University, he is an expert in bats, which might suggest a déformation professionnelle in his interest in darkness, the way an expert in roosters might have a weakness for the dawn. He is able to tell us authoritatively that, though bats do indeed use natural sonar to echolocate their way around, their eyes see well enough in the dark to help in their navigation. (As so often, nature’s secret to survival is not one perfect plan but a little bit of this and a little bit of that.) Of course, Eklöf’s arguments escape the narrow world of roof eaves and pointy ears. Though the book is written as a sort of “Silent Spring” manifesto against the ecological devastations of light pollution, its considerable charm depends on the encyclopedic intensity with which he evokes the hidden creatures of the night.

Agreeably in love with darkness, Eklöf is not entirely a sentimentalist about it. Sex and violence rule the night sky as much as they ruled the drive-in movies that the night sky once superintended. What governs the sunless vistas is not a peaceable kingdom but a fierce contest for life, occasionally made vivid for us by the fiery, bioluminescent nature of its display. The firefly is signalling and winking as desperately as a Raymond Chandler heroine for a mate, until a greedy frog, like a Chandler gangster, stops everything and devours it. Eklöf makes it clear that the great Cambrian explosion of species, which began the evolution of animal eyes that could translate light into images, was set off by the advent of predation and countermeasures to it. Advanced animal evolution—and optical perception—began when creatures realized that they could make a better living by eating one another than by staying in place and absorbing nutrients from the ooze around them. Teeth and shells, claws and hide, rose in a flurry, and among the foremost of the defenses were eyes to sense the presence of a predator.

The difference between light and dark is, in a way, arbitrary: what counts as light and what as darkness depends on what wavelengths we discern. But the nocturnal world gives rise to creatures, equipped with large-pupilled and infrared-sensitive eyes, that see what we cannot and that, under cover of darkness, act as we can only imagine. And so Eklöf’s book is made most memorable by the sometimes wild eccentricities of the life-forms it chronicles. Though his catalogue of catastrophe is real, what one most remembers are the beasts in his bestiary…

Read the whole review here.