Nature was once a “separate and wild province” from human civilization, as Bill McKibben wrote in his famous 1989 call-to-arms, The End of Nature: It was “a world apart from man to which he adapted and under whose rules he was born and died.”

But, claimed McKibben, we have effectively killed off this independent sphere—that wondrous, self-sustaining, life-generating realm which existed for eons before us.

“There’s still something out there,” he said, but “in the place of the old nature rears up a new ‘nature’ of our own devising”—a construct where “each cubic yard of air, each square foot of soil is stamped indelibly with our crude imprint, our X.”

Some now call this evolved world (or new layer of the planet) the “technosphere,” a term coined by Duke University geologist Peter Haff. And it is filled to the brim with stuff. Indeed, there is so much of this human-made stuff—machinery, skyscrapers, packaging, waste, Ikea furnishings—that it’s almost impossible to fathom, let alone measure. And yet—gotta love science!—that is precisely what a team of researchers has tried to do in a recent academic paper.

Their conclusion? Our stuff weighs approximately 30 trillion metric tons. (Yes, the authors used the word “approximately.”) That works out to a mass of over 50 kilos per every square meter of earth’s surface, and one that’s an order of five magnitudes larger than that of the human beings who created it. Or so they estimate.

The diversity of stuff—the manufactured flotsam and jetsam of our daily lives—may even exceed the total diversity of biology throughout Earth’s history, the same research team asserts. This endless assembly of things and devices, moreover, interacts and evolves in its own dynamic, emergent way: “In this sense,” writes Haff (in another paper) “one might say that technology is the next biology.”

It’s a thought-provoking thought.

On the one hand, says Haff, we can no longer live without the “support structure and the services provided by technology”—the communication, transportation, energy, and other networks that developed to make human life on an increasingly crowded planet function in the first place.

On the other hand, we are positively drowning in it. Our days are consumed by consumption, our calendars an endless parade of Presidents’ Day sales, Black Fridays and Cyber Mondays. And each trip to the garage bin gets more laden than the last.

What this stuff-to-trash-to-stuff cycle does to our collective well-being is anybody’s guess. Our so-called e-waste alone has dark, if still imprecise implications for human health, say lots and lots of scientists and public institutions.

As I said, it’s too early to know what the effects of all of this will be. But as we head deeper into a realm of digital health technology, we should perhaps consider that the new whiz-bang thingamajigs we create today will surely end up atop the piles of thingamajigs we created yesterday.

Hmm. It does sound biological, after all. Call it the reproductive cycle of stuff.