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.

We’re accustomed to viewing the world in a human-centric way that says the planet exists for us on some level, and that’s heavily reflected in our culture and religious traditions, including the one I grew up in, where a moody god “so loved the world” that he sacrificed his son to save it. It exists in the techno-optimism of Silicon Valley billionaires who believe that if the planet gets destroyed, they’ll just colonize a new one. But when the weather is doing strange things, it undermines the idea that we are the center of the universe and have potential agency over anything nature can do to us.

About a decade ago, when thoughts of climate apocalypse were further from my mind, I went to see a show at the Hayden Planetarium titled “Dark Universe.” I like space-related things and other things that can be prefaced with “dark” (chocolate, satire, people who are tall and handsome). As the film took viewers to the deepest corners of space accompanied by the calm, dulcet voice of Neil deGrasse Tyson, I learned about the universe and the much longer list of what wasn’t then known about it. The size and scope of various features of the universe were estimated in relation to the earth and timelines in relation to human’s time on earth.

The scale was a reminder of how tiny and fleeting our existence really is. It was glorious and beautiful, and when I stumbled outside into the light, I had what felt like the beginnings of a panic attack brought on by the realization that we live in a delicate ecosystem that is often hostile and could easily destroy us. Then I went home and probably made a to-do list or contributed to a long social media thread about whether a hot dog is technically a sandwich.

These moments of dread come more frequently these days, as catastrophic climate events unfold both slowly and in great, ghastly bursts of wildfire and tropical storms. It’s not the absolute events but the deviation from the norm that is alarming. If it’s 70 degrees in Alabama on Dec. 25, I don’t really notice it because that’s normal, but a few years ago, when it was in the high 60s in Brooklyn for a few days in January, I wondered if I should increase my anti-anxiety meds.

This past June, Brooklyn was covered in a blanket of smoke from Canadian wildfires. The sky was a muted burnt sienna and the air smelled like a barbecue gone severely wrong. I reassured my son, who had many questions, that the neighborhood was not on fire.

It is my job to make my child feel safe, so I answer questions about scary, calamitous things when he asks, but carefully. He is not a sheltered kid and is probably exposed to more of the adult world than many of his peers; he likes creepy things and scary movies and is generally fearless. He gravitates toward questions about death and has asked me whether I’d rather freeze to death or die in a fire so many times that if I didn’t know him, I might be concerned that he was planning something. But he still experiences extreme weather as a novelty and not a threat. I hope he’s much older before he notices a drastic temperature change or more smoke in the air or the fact that it’s New Year’s Eve and there’s no snow on the ground at home. I believe humans can reverse some of the harm we’ve caused to the environment — we’ve done it before, which is why the state of the ozone layer is no longer a problem on the heels of the Montreal protocol — so I’m not a total pessimist. But I am worried.

It finally snowed a bit in Omaha, on Christmas Day, no less — a bit of temporary relief. I’m not worried that my grandchildren, if they ever materialize, will grow up not knowing what snow is, as my friend suggested. But I wonder if, somewhere down the line, one of my descendants will build the last snowman in Omaha.