Nature, we learn, seeks to establish and maintain equilibrium. According to a study published late last year in Nature, Earth did just that, though not by design. It just so happens that the year 2020 marked the point at which anthropogenic mass (the mass of manmade inanimate objects) equaled Earth’s total biomass (the total mass of all living taxa, including the mass of humans and our livestock). Part of the reason our artifacts outweigh the biomass is that we’ve chipped away at the difference in the process of their creation, consuming a significant portion of what Earth has to offer along the way. For example, while the collective weight of humanity comprises only a fraction of a percent of the planet’s total biomass, we have cut global plant mass in half through farming and other human activities such as deforestation.
What’s more, the pace at which the amount of anthropogenic mass has caught up with Earth’s total biomass has accelerated to a startling degree over the last 120 years. During that period, anthropogenic mass doubled approximately every twenty years. Put another way, this is the equivalent of each human being generating mass in excess of his or her own body weight every week. Anthropogenic mass accounted for 3 percent of total biomass in 1900; now it’s on the cusp of overtaking it.
What exactly do we have to show for all this manmade stuff? The materials that contribute to anthropogenic mass function almost as time capsules, different epochs defined by certain tools, products, and activity: construction materials from the advent of the twentieth-century metropolis, or e-waste from our current consumer culture. Indeed, major global events such as economic depressions and wars all have left marks in the form of their contributions to the amount of manmade mass.
All of this culminates this year, when the weight of our labors will now exceed the total global biomass. The trend brings with it a stark warning: According to the Nature study, at this rate, by 2040 anthropogenic mass (including our trash—the authors note that the mass of plastics currently outweighs all terrestrial and marine animals combined) will triple the amount of dry biomass on Earth. How to slow down this trend is far from clear, but it begs for deeper reflection on our individual and collective actions, the aggregate effect of which, on a daily basis, we never notice.