Once upon a time, in the room that would be my first child’s nursery, I wondered what to tell her about our vanishing world.

Through the generosity of family and friends, a modest library of children’s books filled our shelves, including four copies of “The Very Hungry Caterpillar” and three copies of “Goodnight Moon.” Like so many new parents, we couldn’t wait to read to our child.

But on that day nearly three years ago, I held the books that had been my childhood favorites decades before and questioned whether I should share them with her. Each was now a classic: “Where the Wild Things Are,” “Swimmy,” “The Story of Babar,” “A Snowy Day,” “Make Way for Ducklings.” But all of these books, first published in the early and mid-20th century, come from a time when the world was a different place.

Especially different was the world of wild things, oceans, winters and even common birds. Since the oldest of the books, “Babar,” was published in 1931, Africa’s elephant population had dwindled from 10 million to roughly 400,000. Since “Where the Wild Things Are” was published in 1963, the world had lost an estimated two-thirds of its wildlife. Will we have fewer snowy days going forward, and fewer ducklings to make way for? Over the past five decades, North American skies have lost nearly three billion birds.

As I paged through Leo Leonni’s “Swimmy,” in which a small black fish travels above an ocean floor colored with life — oceans that are increasingly imperiled — I thought of the marine biologist Sylvia Earle, who, when asked where she would dive if she had her choice of location, replied, “Anywhere, 50 years ago.”

[Sign up for Love Letter, our weekly email about Modern Love, weddings and relationships.]

This loss has happened in my lifetime. The wild world my favorite books had encouraged me to love has been under assault. Becoming aware of this loss had led me to serious grief and now to a steady undercurrent of “solastalgia” — the distress caused by environmental change, a feeling of homesickness for the place we still live.

And so, I found myself wondering if reading these books to my daughter would in a way be a lie. Was it fair to tell her stories of healthy ecosystems and the steady seasons to which we’ve become accustomed?

I was never in a hurry to be a father. Between graduate school, my first teaching jobs and a series of relationships, I enjoyed being a single man, close to my parents, with a beloved bird dog who accompanied me nearly everywhere. I also was studying environmental literature — stories of wonder and adventure but also of loss and impending loss. Stories about issues (toxic pollution, thawing permafrost, ocean acidification) that if honestly considered would make anyone think twice about bringing a child into the world.

Still, I mostly assumed I would become a father someday, though I didn’t expect that it would take until I was nearly 50. I met a smart woman who told me how being read to as a child led her to a love of books and a career in academia, and within two years we were married, then pregnant, then organizing nursery shelves.

I had written a book about how we no longer see many of the stars our ancestors saw because there’s so much artificial light in the sky, a project sparked by memories of looking for shooting stars with my father when I was 5.

“What’s it going to be like,” asked my wife, “when you take your daughter to see the night sky for the first time?”

She really was asking what it would be like to share the moon and stars with my daughter for the rest of my life.

Lying awake at night, I imagined what else I would share. The bird dog I had been devoted to had died a few years before, and the life I had given her was the best thing I had yet done with mine. But to be someone’s father, to introduce a child to desert rain and autumn leaves, to Mozart and Led Zeppelin, to green chile enchiladas and real maple syrup — with endless wonders between — felt thrilling.

But I lay awake for other reasons as well.

I had a friend whose 5-year-old son had loved bedtime stories that featured elephants, lions, penguins and bears. The messages sent by such books were the same as those sent by the clothing and toys that had surrounded him since birth: Animals are wise and kind, they fill our world, they are our friends. So, it stunned his mother when he said: “No more stories about animals.”

“Why?” she asked.

“Because it makes me sad that they are disappearing.”

I had chosen to become a father knowing well the dire predictions, the destruction that leaves me quiet. Now, with an actual child on her way, I wondered again about telling her stories of a world diminished.

When I saw my daughter for the first time on ultrasound, she was eight weeks in the womb and reminded me of a peanut-sized bear cub. Her head was half of her, and her hands were held alongside her head as though she were listening closely to faint signals coming through her headphones from some faraway land, listening for what has passed mixed with what might be.

She was born months later at midnight, with colors vivid and shining: the milk-white cord, the bright maroon blood, the deepest purple of the placenta. As I held her for the first time, she was tiny and quiet, regarding me with a look of, “So?”

But the instant emotions you’re told you will feel? Those came slower, over months, and with a surprise.

It started with stories of children lost or sick. Before, of course, I sympathized, but now every child felt partly mine. Even make-believe children — when a television plot included a teen daughter’s rough kidnapping, I turned it off and climbed the stairs, lifted my daughter from her crib and held her close.

Years ago, a friend said when he heard the news of Sandy Hook, he raced across town to hold his 6-year-old. I remember nodding with assumed understanding; now I actually knew that urge. My daughter’s innocence and openness to the world had been entrusted to my care. To love something so much is frightening, but it’s also beautiful, a feeling I’m grateful I didn’t go through life without.

I knew I would love my child. But I couldn’t have known what that love would feel like. And my love for the natural world, my grief over its fate? Having a child made me feel those emotions even stronger.

About six months after my daughter’s birth, while browsing in a local bookshop, I discovered a newly published picture book: Cynthia Rylant’s “Life.” After paging through, I pulled my wife close. Brendan Wenzel’s playful artwork depicted a world still made of wild things and accompanied Ms. Rylant’s simple text that “life begins small … (and) is not always easy … (but) in every corner of the world, there is something to love. And something to protect.”

“You’re about to buy this book, aren’t you?” she said.

Yes. In Ms. Rylant’s book I had found a contemporary response to the classics I loved. This book seemed to say: Even with all the loss, so much remains. My feelings for the world had merged with those for my daughter. To love and protect one was to love and protect the other.

The old ways of paternal protection hardly seem relevant anymore. A shotgun on the porch? No. To protect her now means to encourage her to love with everything she’s got — and, eventually, to let her learn that the more intensely you love something, the more it can hurt. How will she gain agency and purpose if she doesn’t know how to move from fear and grief to courage and joy?

At 2-plus years old, my daughter is blissfully unaware of Covid-19, knows nothing of climate change, has no sense of what has been and still may be lost. Instead she is astonished by the everyday, at the window exclaiming, “big truck!” and “mail man!” Outside, it’s “beetle!” and “moon!”

The other morning, she followed a path alone into the woods for the first time. One can only imagine what that must be like for a toddler. Maybe it’s like entering a picture book published way back when — or stepping forward into a new story of a world we could create. She moved cautiously, but steadily, as though a brightly colored animal friend could be just around the bend.

Paul Bogard, who lives in Minneapolis, Minn., and teaches at Hamline University, is the author of “The End of Night” and other books.

Modern Love can be reached at modernlove@nytimes.com.

To find previous Modern Love essays, Tiny Love Stories and podcast episodes, visit our archive.

Want more from Modern Love? Watch the TV series; sign up for the newsletter; or listen to the podcast on iTunes, Spotify or Google Play. We also have swag at the NYT Store and two books, “Modern Love: True Stories of Love, Loss, and Redemption” and “Tiny Love Stories: True Tales of Love in 100 Words or Less.”