People make up about 0.01% of all living matter on Earth, a sliver next to the planet’s plants, bacteria, fungi and animals. By that measure we are a very small species.

And yet the stuff we make now weighs more than all of it put together.

In December 2020, Nature published a study by Emily Elhacham and colleagues at the Weizmann Institute of Science. They found that the weight of everything humans have built crossed the weight of everything alive in 2020.

So we have two figures to hold together: we are a fraction of a percent of life, and our concrete, steel and asphalt now outweigh all of it.

The two numbers side by side

A 2018 count put total living matter at around 546 billion tonnes of carbon, with plants making up about 82% of it. Humans come to about 0.06 billion tonnes of carbon. That’s where the 0.01% comes from. Ranked by sheer weight, we barely register.

The built side is what changed the picture. The Weizmann team gathered global data on what humans have produced going back to 1900 and tracked the total weight of human-made things still in use. Measured against a living total they put at roughly 1.1 terratonnes, the built total drew level in 2020.

The comparison isn’t really people versus nature. It’s everything we make versus the entire living world, and in 2020, the two reached a tie.

We are not ecologists, geologists, or climate scientists, and nothing here is a verdict on how you should live. This is a reading of one study and the coverage around it. The figures are estimates with real uncertainty attached, and a planet-scale average is not a statement about any one place.

How the crossover got pinned to 2020

The human-made total covers the concrete, gravel, bricks, asphalt, metals and plastics that make up our buildings and infrastructure, weighed and counted while still in use. The team estimated the world makes around 30 billion tonnes of new material a year, and that this amount has been doubling roughly every 20 years. .

They put the meeting point at 2020, though with a wide margin of give or take six years. Co-author Ron Milo called the result a sort of “big picture” snapshot of the planet in 2020, which is worth taking at face value. It is one team’s estimate of when two huge, hard-to-measure totals crossed, not a date stamped on a receipt. 

Why concrete carries the built side

If you’re picturing all this as a mountain of gadgets, think again. It’s mostly buildings and roads.

Concrete alone makes up about half of all human-made mass, with bricks, asphalt, metals, plastic and everything else accounting for roughly 19 percent between them. The crossover, then, is mostly a story about gravel and cement, the least glamorous things we produce.

Plastic is the smaller figure that tends to stick in the mind. By the study’s reckoning, the world’s plastics now weigh about twice as much as all the planet’s land and sea animals combined. A small slice next to concrete, but it makes a point concrete doesn’t: even the stuff we treat as throwaway now outweighs the animal kingdom.

The living side isn’t standing still

The lines also met because one of them has been falling. The built total climbed, but the living total dropped over the long run.

Plant life has roughly halved since farming began about 12,000 years ago, mostly through clearing forests. The crossover isn’t only about us building more. There’s also less life left to outweigh than there once was.

How much to read into a crossing point

It’s tempting to treat a number like this as a verdict but lead author Elhacham framed the work as adding perspective rather than passing judgment. By contrasting human-made mass and biomass over the last century, she said, “we bring into focus an additional dimension of the growing impact of human activity on our planet.” More a way of seeing, than a scorecard.

There’s also honest disagreement about where the line falls. Geologist Colin Waters has noted that if you also count the rock and soil moved to reach the materials, the crossover shifts back to around 1977. Change what you count and the date moves by decades, a good reminder that 2020 is a choice about accounting as much as a fact about the world.

The study estimates that “for each person on the globe, anthropogenic mass equal to more than his or her bodyweight is produced every week”. Fridolin Krausmann, who reviewed the paper, expects that “in the next 20 years, we will get as much waste as from the last 110 years together.” 

The 0.01% figure lets us think of ourselves as small, and biologically we are. The output figure says the smallness stops at our bodies. Milo’s own framing is the one we keep returning to: “We cannot hide behind the feeling that we’re just a small species, one out of many,” he argues, noting that “we have become a dominant force.”