So I told Hank I was scared.

“The species will survive this,” he answered, a little hitch in his voice.

“The species will survive this? That’s all you’ve got for me???”

He paused. I could hear the tremble in his breath, the tremble he’s been hearing in my breath our whole lives. “That’s what I’ve got for you,” he said after a moment.

I told Hank I’d bought sixty cans of Diet Dr Pepper, so that I could drink two for each day of the lockdown.

And only then could I hear the old smile, the my-older-brother-really-is-a-piece-of-work smile. “For someone who has spent four decades worrying about disease pandemics,” he said, “you sure don’t know how disease pandemics work.”

One rule of retail marketing maintains that to maximize sales, businesses need to create a sense of urgency. Mega-sale ends soon! Only a few tickets still available! These commercial threats, especially in the age of e-commerce, are almost always a fiction. But they’re effective, an echo of our apocalyptic visions: If we feel a sense of urgency about the human experiment, maybe we’ll actually get to work, whether that’s rushing to save souls before the Rapture or rushing to address climate change.

I try to remind myself that back in the fourth century, Martin of Tours’s eschatological anxiety must have felt as real to him as my current anxiety feels to me. A thousand years ago, floods and plagues were seen as apocalyptic portents, because they were glimpses of a power far beyond our understanding. By the time I was growing up, amid the rise of computers and hydrogen bombs, Y2K and nuclear winter made for better apocalyptic worries. Today, these worries sometimes focus on artificial intelligence run amok, or on a species-crushing pandemic that we have proven ourselves thoroughly unprepared for, but most commonly my worry takes the form of climate anxiety, or eco-anxiety—terms that did not exist a few decades ago but are now widespread phenomena.

Humans are already an ecological catastrophe. In just 250,000 years, our behavior has led to the extinction of many species, and driven many more into steep decline. This is lamentable, and it is also increasingly needless. We probably didn’t know what we were doing thousands of years ago as we hunted some large mammals to extinction. But we know what we’re doing now. We know how to tread more lightly upon the earth. We could choose to use less energy, eat less meat, clear fewer forests. And we choose not to. As a result, for many forms of life, humanity is the apocalypse.

There are worldviews that embrace cyclic cosmologies—Hindu eschatology, for instance, lays out a series of multibillion-year periods called kalpas during which the world goes through a cycle of formation, maintenance, and then decline. But in linear eschatologies, the end times for humanity are often referred to as “the end of the world,” even though our departure from Earth will very probably not be the end of the world, nor will it be the end of life in the world.