Have you ever felt weighed down by your material possessions? The boundless variety of stuff that humans manufacture — tractors, buildings, ballpoint pens, Hello Kitty backpacks — has serious heft: 30 trillion metric tons, a new study estimates. That’s about 50 kilograms for every square meter of Earth’s surface.
The human-made “technosphere,” all the manufactured goods around today, surpasses the natural biosphere in mass and variety, geologist Jan Zalasiewicz of the University of Leicester in England and colleagues report online November 28 in The Anthropocene Review. Books alone, at about 130 million titles, surpass the estimated 8.7 million eukaryotic species on Earth. The technosphere is one measure of how humankind is reshaping the planet (SN: 10/15/16, p. 14), the researchers note.