Human civilisation is made of a number of man-made materials and objects, but just how much of these things have we made and produced at this point? And in this process, how much of the natural world have we destroyed?
A new analysis has found that we have produced so many man-made things that they will soon outweigh all the living things on earth.
It is currently estimated that humans have produced 1.1-teratonnes or 1 100 000 000 000 tonnes of made-made mass. At the start of the 20th century, human-produced objects were equal to just 3% of global biomass.
The analysis was published on Wednesday, December 10 in the scientific journal Nature, and was conducted by a group of researchers from Israel’s Weizmann Institute of Science.
The researchers divided human-made objects into six categories, including concrete, aggregates (including materials like gravel), bricks, asphalt, metals and “other” materials, which includes plastic, wood used for construction, as well as paper and glass.
The man-made mass is dominated by concrete, aggregates, asphalt and bricks as these are the foundations of modern buildings and roads. Pollution, however, was not factored into the calculations, but if this were added, the year that man-made mass outweighed that of the natural world would have shifted to 2013 instead of 2020.
Looking at biomass, the authors found that plants represent the overwhelming majority of living things – approximately 90% – followed by bacteria, fungi, single-celled archaea, protists, and animals. This also includes humans themselves, as well as crops and livestock raised for food.
Since the first agricultural revolution began approximately 12 000 years ago, humans have cut global biomass nearly in half, from 2-terratonnes to just 1.1-terratonnes.
Although a large part of the Earth’s land is used for the growing of crops, this total mass is still dwarfed by human-caused losses in the biosphere. Activities such as fishing, hunting and the rearing of farm animals have also greatly cut into the overall natural biomass.
On average, materials outweighing the bodyweight of every single person on the planet is produced on a weekly basis. If this pace continues, the man-made mass will increase to 3-terratonnes by 2040.
“The study provides a symbolic and mass-based quantitative characterization of the Anthropocene – the geological age of ‘the era of humanity,” two of the study’s authors, Emily Elhacham and Ron Milo, said in response to questions via email.
“Given the empirical evidence on the accumulated mass of human artifacts, we can no longer deny our central role in the natural world. We are already a major player and with that comes a shared responsibility.”