Humanity has reached a new milestone in its dominance of the planet: human-made objects may now outweigh all of the living beings on Earth.
Roads, houses, shopping malls, fishing vessels, printer paper, coffee mugs, smartphones and all the other infrastructure of daily life now weigh in at approximately 1.1 trillion metric tons—equal to the combined dry weight of all plants, animals, fungi, bacteria, archaea and protists on the planet. The
creation of this human-made mass has rapidly accelerated over the past 120 years: Artificial objects have gone from just 3 percent of the world’s biomass in 1900 to on par with it today. And the amount of new stuff being produced every week is equivalent to the average body weight of all 7.7 billion people.
The implications of these findings, published on Wednesday in
Nature, are staggering. The world’s plastics alone now weigh twice as much as the planet’s marine and terrestrial animals. Buildings and infrastructure outweigh trees and shrubs. “We cannot hide behind the feeling that we’re just a small species, one out of many,” says study co-author Ron Milo, who researches plant and environmental sciences at the Weizmann Institute of Science in Israel. These numbers should be a wake-up call, he adds. They tell us “something about the responsibility that we have, given that we have become a dominant force,” Milo says.