Alex Foster’s debut novel, “Circular Motion,” is precisely 360 pages long, an appropriately exact total for a story about a near future in which international travel has been revolutionized by the “westward circuit,” a vast collection of “circuit vessels” that constantly orbit Earth without landing. Built and operated by a giant corporation, the westward circuit cuts down travel time by so much that it’s possible, for instance, for the narrator and his friends to do a “world crawl,” a pub crawl of the whole planet.

The consequence of all this global circumnavigating is “day contraction,” the speeding up of Earth’s rotation, leading to shorter and shorter days. Since the thousands of vessels only travel from east to west, the effect is like “thousands of tiny logrunners … all moving roughly west and spinning the Earth eastward beneath them.” Tanner Kelly, that narrator, works as an assistant for Victor Bickle, a once-independent whistleblower hired by CWC, the company responsible for the westward circuit, to rehabilitate its image and deflect attention from protests and backlash.

As time continues to accelerate — as the days go from 24 hours to 22, to 12, to nine, to two — unpredictable catastrophes proliferate, like climate change on fast-forward. Initially, schedules are adjusted and correctives are put in place. Eventually, though, the tides swell toward the equator, gravity weakens, and a vast, planet-covering protective layer known as the Shell needs to be constructed around Earth to combat these effects and prevent further cataclysm.

But if this makes it sound as if “Circular Motion” operates only as a lofty, idea-driven, futuristic meditation on technology, rest assured that what ultimately recommends Foster’s novel are its most terrestrial elements — the characters. As Tanner adjusts to life in London, where his job with CWC eventually takes him, he begins a relationship with Miguel. It’s Tanner’s first romantic and sexual experience, a bumpy and vulnerable rite for anyone, made more so in this case by the prejudice of Tanner’s domineering, off-the-grid father. Tanner and Miguel’s romance is rendered much more delicately and humanely than many near-future dystopian novels might have handled it. Such care in characterization keeps “Circular Motion” grounded, so that its more daring narrative leaps have something anchoring them and don’t fly off into the sky.

In a parallel story, a 15-year-old named Winnie Pines navigates high school life in San Francisco. Although she was born in the same Alaskan town as Tanner, Winnie didn’t grow up there. Her single mother struggles with drug addiction and falls into a coma as a result. Winnie, who now lives with her aunt and uncle, is not very socially adept, a fact that isn’t helped by her habit of shocking herself with batteries in the back of class. Soon, though, she befriends a pair of politically active girls at school, who convince her to join their protests against CWC and day contraction. After her friends get arrested at one such demonstration, Winnie feels both left out and stuck in the middle of the two much more sophisticated girls. A hurricane blasts San Francisco, with devastating effects for Winnie. Five years later, she is in her early 20s, working for a start-up tech company. Every detail of her biography – from her self-harm to her feelings about her mother – feels lived-in and tenderly wrought.

Foster has a knack for delicately balancing the emotional stakes for these deeply drawn characters with the dispensing, at a breakneck pace, of a great deal of information, exposition and global developments. By the time the book’s plotlines collide at a gala in Beijing, Tanner and Miguel’s relationship is just as complex and volatile as the political climate surrounding them. As for Winnie, her presence in the novel is given new purpose after a revelation about her family. All developments are skillfully constructed, evolve organically from where they start and grow more interesting than those starting points — in the same way that the Shell, the protective layer built around Earth, is an ingenious, natural and even more fascinating concept than the clever one that initiated it, the acceleration of the planet’s rotation. Foster doesn’t rest on his fun and original ideas; he nurtures them, cultivates them with thoughtful challenges and unexpected turns, until out of them emerge new ideas, complicated and earned.

With shades of emotional planetary disaster novels like Karen Thompson Walker’s “The Age of Miracles” and politically charged climate fiction like Stephen Markley’s “The Deluge,” “Circular Motion” comes from a writer capable of two things often misconstrued as counter to each other: deep, rich characters and elaborate, challenging ideas. The people give credence to the imaginative story, and the story creates stakes for the people. The corporate causes of climate change, as well as our complicity in their corruption, might very well bring about the end of human civilization, but it will be a slow death, a whimper. “Circular Motion,” literally and figuratively, speeds things up to spotlight our folly. A quicker death for the world, though, may be Foster’s most sympathetic fictional act.

Jonathan Russell Clark has written about books for Esquire, the New York Times, the Los Angeles Times and others. He is the author of “Skateboard” and “An Oasis of Horror in a Desert of Boredom.”