When Lydia Millet was a child and her guinea pig Trudy died, she asked her parents if anyone had ever committed suicide because of a pet’s death. “Probably not,” they responded diplomatically. For a few hours, Millet stared at her bedroom wall, sobbing and inconsolable. Then the grief passed: “It had gotten boring,” she recalls, “and I was quite hungry.”

Millet’s first work of nonfiction, We Loved It All: A Memory Life, is a sweeping study of climate change, greed, human hubris, loss, and the possible end of life as we know it, but it begins with moments like this, told from the perspective of youth. The moods of childhood may be imperious, hysterical, and yielding, but they may also reveal parts of the world that adults have been trained to ignore. Those feelings of grief about Trudy, for example, were also feelings of guilt. Like many children, Millet often forgot to remove piles of the animal’s droppings from her cage or, too lazy to retrieve lettuce from the fridge, fed her pellets from a plastic bag. But Trudy was “just a guinea pig,” Millet assured herself, reciting a line she’d heard from adults. What did she care?

There is a risk, in examining a pet’s preference for lettuce or hay, of appearing excessively concerned about a category of domesticated animal that humans already lavish uncommon attention on. But Millet’s focus is more diffuse: She’s interested in the received ideas about nonhuman life that we know, instinctively, to be overstated and false. Take that inflection: “just a guinea pig” (or dog, cat, bird, cow, etc.). What does it really mean? Consider that a crow can remember a human’s face and even identify, based on one’s expression, whether that person is friendly or hostile. It might be foolish to project the emotions we feel onto animals, but it seems equally absurd, Millet writes, to “presume that people have exclusive access to impulses like love or jealousy.” And by denying that other forms of life have interiority and depth, we’ve deprived ourselves of the opportunity to, as Millet puts it, “search into an abyss of information we’ve barely begun to plumb.”

We Loved It All is an attempt to examine that abyss—the expanse of life we usually relegate to the background of our own. Instead of transforming animals and plants into objects of projection, symbols of our own loneliness or autonomy or avarice, she surveys the strangeness of nonhumans, like the eccentric mating rituals of spiny echidnas or finches that talk to their embryos. Weaving together memoir, cultural critique, and scientific journalism, Millet tells a story of human existence and its transformation alongside nonhuman existence. It’s both capacious and personal, linking memories from Millet’s childhood and later marriage to questions about the planet, time, systems of governance and trade, machines, and mass extinction.

Millet’s writing has a certain urgency, of course, because many of these forms of life are swiftly disappearing. “Maybe we haven’t spoken up for the others partly because of the unconscious, innate quality of our ties with them,” she observes. “Possibly we need the telescopic view—the distance of forgetting and the jolt of recognition as a remembrance surfaces—to know what we adore.”

Behind Millet’s quest to catalog the multitude of life is a deceptively simple hypothesis: To get people to do something about the imminent collapse of our natural systems, we might need a new method of persuasion. Perhaps instead of appealing to our own self-interest, to moralism or economic pragmatism, we need to start with something more fundamental: an appeal to our attention. If this sounds obvious and meek (just look at the flowers!), consider that, in a society obsessed with wealth, power, and productivity, the attempt to sustain an interest in things that don’t clearly advantage us, that aren’t a means of self-improvement or amassing resources, is no easy feat.

Noticing the presence of others among us won’t erase the damage that we’ve already done; nor is it, on its own, a solution or an end. But it may be the best place to begin. After all, what we pay attention to, we tend to care for and even love; and what we love, we make sure doesn’t disappear.

Writing about animals, plants, insects, fungi, and other life-forms that are, to varying degrees, speechless and unreachable is exceptionally difficult because of all the things we don’t know. How does a fly experience time? Does a frog feel depressed when its mating calls aren’t returned? What’s it like to see colors in the ultraviolet spectrum? Or to hear the distant rumblings of a storm hundreds of miles away? Or to be the very last Pinta Island tortoise? How to write from the perspective of what we don’t understand?

Our answer seems to be, simply, don’t. In most novels and movies, nature shows up to set a mood, like the rainstorm that presages a romantic confession. Sometimes, nonhuman life becomes a conduit for a lonely, grieving, or otherwise lost person to find herself. Occasionally, we imagine other creatures as humans, as in the children’s books populated by amiable or mischievous talking animals.

Millet, who works as an editor and staff writer at the Center for Biological Diversity, has spent much of her career reckoning with the challenges of writing about the nonhuman world. Her fiction often imagines human encounters with other creatures, real or fantastical. In Mermaids in Paradise, a huge resort company tries to turn a colony of mermaids into a theme park; in Omnivores, a man’s fixation with collecting dead insects evolves into feverish cruelty. Her latest novel, Dinosaurs, follows a benign and somewhat hapless bachelor named Gil as he looks after his neighbors’ children, cares for a grieving widow, and volunteers at a domestic violence shelter, where he escorts the women on shopping trips. Gil takes an analogous interest in the animal life around him: the turquoise and purple hummingbirds that float like “hovering jewels,” the woodpeckers that nest in underground holes, the family of hawks that perch on saguaro cacti. When several dead quail appear in his yard, Gil tracks down the hunter and tells him: “You need to stop shooting my birds.”