Every Christmas my husband and I pack up ourselves and our now 8-year-old and leave Brooklyn for a visit to either Nebraska (where my in-laws live) or Alabama (where my family lives). If we’re headed to Omaha, we pack heavy layers because the weather is somewhere between arctic tundra and what it might feel like to live inside an Icee. If it’s a year when we head to Wetumpka, we pack moderate layers but also short sleeves and maybe even shorts, since 60-to-70-degree Christmases are not unheard-of there.

This past year was an Omaha year, and we arrived on the 22nd to find that the weather was very mild — almost 50 degrees — and there was no snow. More unusually, there had been no snow for the entire month of December. Aside from some brief and very sparse flurries, it hadn’t snowed in Brooklyn, either, in November or December. I’m an incorrigible heat seeker, and the phrase “wintry mix” fills me with despair. But even so, the lack of cold and ice in 2023 felt unsettling.

One reason is easy to quantify: Last year’s warmer temperatures happened globally, and they’re a reminder that without significant climate change interventions we could have a future in our lifetimes where higher temperatures are the norm. Another reason — a harder one on the psyche, but increasingly omnipresent — is the sense that balmy holidays are a preview of something darker: bigger climate extremes, more natural disasters, the specter not of a world where humans suffer through these things and find ways to survive but where we’ve made the planet so uninhabitable that, in the longer run, the planet survives but we don’t.

I was thinking about this while standing outside a science museum a couple of days ago with a friend. We were talking about the weather, but not the kind of small talk when you have nothing else to say. “I’m not sure our grandkids will even know what snow is,” she said, with a wry “I’m kidding, but I’m not” laugh. She and her family were leaving for a ski trip the next week, uncertain whether there would be enough snow.

For superstitious people like me, who believe that if we think through the worst-case scenarios, the products of our imagination will serve as talismans to ward them off, the disappearance of snow is just one unfortunate potential future scenario. Inasmuch as this is not a defect in the personal architecture of my brain, engaging with the idea of a world without humans is what Eugene Thacker, an author and professor who writes about horror and philosophy, calls “cosmic pessimism.”

“Its limit-thought is the idea of absolute nothingness,” writes Mr. Thacker, “unconsciously represented in the many popular media images of nuclear war, natural disasters, global pandemics and the cataclysmic effects of climate change.” Just before we left for Omaha, I had been reading his book, cheerily titled “In the Dust of the Planet,” in which he refers to the human inability to fully confront this “absolute nothingness” as a unique horror, and while he’s not talking about horror movies, per se, it’s easy to imagine an apocalyptic thriller that begins with the sudden disappearance of snow.