Worldwide flooding. Massive Canadian wildfires. Monster hurricanes. Record-breaking heat waves. Sauna-level sea temperatures. The loss of billions of tons of Arctic and glacial ice. The existential question of the summer was, Could this be the beginning of the end? Three new speculative novels for young readers answer yes, with varying degrees of resignation and sorrow, bitterness and hope.

In PROJECT F (Random House, 224 pp., $17.99, ages 8 to 12), by Jeanne DuPrau (“The City of Ember”), catastrophic climate change serves as the backdrop for the action. Set hundreds of years after fossil fuels brought civilization to its knees; after the wreckage of cars and trains was piled high into twisted, rusting-metal mountain ranges, and millions, if not billions, of people died, the novel follows Keith Arlo, an average 13-year-old who stumbles upon a secret program to bring flight to the masses using jet packs powered by a mysterious substance called “black dust.”

Through a series of fortunate coincidences, Keith becomes an eager test pilot for the jet pack, the creation of an overly enthusiastic inventor named Malcolm Quinsmith, a man blind to the cost of reintroducing fossil fuels to a world nearly destroyed by them. More arrogant and shortsighted than evil — though there may be little moral difference when you consider outcomes — Malcolm represents us, DuPrau suggests.

Keith’s journey from ill-informed, self-interested teenager to responsible citizen-of-the-world is nicely handled. It takes an Icarian flight, literally and metaphorically, to enlighten him.

Reluctant readers will enjoy the brisk pace. And because the world with which today’s kids are familiar is long gone by the time the story begins, the horrors of a complete climate collapse remain comfortably in the distant past.

Comfortable is a good word to describe Patricia Forde’s THE GIRL WHO FELL TO EARTH (Little Island, 288 pp., paperback, $12.99, ages 10 and up). The most casual reader of science fiction, young or old, can snuggle cozily into the arms of this novel, from the title (change “Girl” to “Man” and you have Walter Tevis’s 1963 classic), to the setup (an advanced race of humanoid extraterrestrials decides it’s time to pull the plug on the human experiment), to the action (our heroine, the 14-year-old half-human Aria, pitted against a foe far more diabolical, and dumb, than he appears, at first aids and then tries to stop the genocide), to the merciful lesson she learns: Hey, humans aren’t so bad after all! (Since the novel is set in the present, climate change is just one of many human-caused crises on display.)

This is well-trodden ground, but the plot skips merrily along. Aria is a likable protagonist, and her confusion over her place (and ours) in the universe is both touching and funny. Forde (Ireland’s current children’s literature laureate) is at her best in these moments. She had this reader disturbed in a delightful way by such questions as, What if pigeons were actually drones that spied on us? and What if Mozart was really an alien?

Then there’s Donna Barba Higuera’s ALEBRIJES (Levine Querido, 336 pp., $18.99, ages 10 and up), a book my tween self would have flipped over. Centuries after the collapse of civilization, presumably due to our screwing around with our fragile ecosystem, two groups of survivors cling to life: the ruthless, ruling Pocatelans and the nomadic Cascabeles, who made the mistake of wandering into the Pocatel Valley back in the day, after which they were promptly segregated and subjugated. Life for the Cascabel orphan Leandro Rivera, 13, and his little sister, Gabi, 9, consists of petty thievery and digging up blighted potatoes, until Leandro rescues Gabi from certain banishment for stealing a strawberry. This selfless act sets in motion an adventure that soars above the dystopic fog.

Higuera (author of the 2022 Newbery and Pura Belpré Medal winner “The Last Cuentista”) has created a future world that has much to say about our present one. Individual responsibility, class consciousness, the power of forgiveness, the exploitation of a despised minority, the brutality of fascism (the potato blight inspires the Pocatelans to launch a pogrom-esque “thinning”), the eternal hope of the oppressed everywhere for a Promised Land (here called La Cuna, or the Cradle) are all in these gorgeously designed pages, with spot illustrations by David Álvarez. Plus the very cool concept of embedding consciousness into surviving Old World tech called alebrijes: brightly colored, lifelike drones in the form of hawks, eagles, cats, wolves, even a chameleon.

Leandro finds himself inside a tiny hummingbird, allowing him, and us, to see the world through the eyes of this beautiful, fragile and fierce creature. It’s a brilliant choice by Higuera, a writer who knows her way around metaphor. “The smallest flap of wings can change the course of history,” she writes. Thank god for that. Given the sobering turn in climatic events, it’s well past time for some wing-flapping.

Rick Yancey is the author of The Monstrumologist series and “The 5th Wave,” among other books for young readers.