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Geosynthetics can help preventing further steep increase in use of anthropogenic mass materials.

Human-made materials now equal weight of all life on Earth. The amount of concrete, asphalt, metal, and plastic on Earth is growing fast. This year may mark the point when artificial stuff outweighs living things.

While the mass of Earth’s life forms stands at about 1.1 trillion metric tons (1.2 trillion U.S. tons) and has not changed much in recent years, the so-called “anthropogenic mass” of artificial materials is growing exponentially. The mass of everything people have built and made, from concrete pavements and glass-and-metal skyscrapers to plastic bottles, clothes, and computers, is now roughly equal to the mass of living things on Earth and could surpass that this year, according to research published today in Nature.

The finding may bolster the argument that Earth has entered the Anthropocene, a proposed geologic epoch in which humans are the dominant force shaping the planet. As senior study author Ron Milo of the Weizmann Institute of Science in Rehovot, Israel puts it, the world is undergoing a material transition that “happens not just once in a lifetime, but once in an era.”

The use of geosynthetic products can, in many applications, prevent or reduce the use of materials such as gravel, fill, concrete or, in road applications, asphalt. This has a positive effect on energy demand and carbon footprint (see LCA studies on this website), but also prevents a steep increase of artificial material used in construction and building industry.

While that insight is more symbolic than scientifically meaningful, the material scale of the human enterprise helps explain how we’ve managed to transform global nutrient cycles, alter the climate, and drive myriad species to the brink of extinction.

This isn’t the first attempt to weigh humanity’s impact on the planet. In 2016, a team of scientists estimated the weight of the “technosphere”—including not just wholly artificial buildings and products, but also the approximate weight of the land and seafloor that we’ve excavated, modified or trawled to build cities, plant crops, raise livestock, and catch fish. They came up with a figure of 30 trillion tons. Other recent studies have tracked changes just in the biological world, such as the amount of carbon stored in plants or the number of chickens on the planet.

But to the authors’ knowledge, there hasn't been a comprehensive analysis looking at changes in the weight of the artificial and biological worlds simultaneously but separately. That has made it difficult for scientists to draw an apples to apples—or apples to iPhones—comparison.

At the start of the 20th century, the mass of human-created stuff weighed in at 35 billion tons, or roughly 3 percent of global biomass. Since then, anthropogenic mass has grown exponentially to approximately 1.1 trillion tons today. It’s now accumulating at a rate of 30 billion tons a year, which corresponds to each person on Earth generating more than his or her own weight in manufactured stuff every week.

Most of that stuff is concrete—humanity’s favorite building material—followed by gravel, bricks, asphalt, and metals. If current trends continue, these manufactured materials will weigh more than twice as much as all life on Earth by 2040, or about 2.2 trillion tons.

Roughly 90 percent of the living world by weight, meanwhile, is composed of plants, mostly trees and shrubs. But while humans manufacture ever more materials each year, the weight of Earth’s plants has held relatively steady, due to what the authors describe as a “complex interplay” of deforestation, forest regrowth, and vegetation growth stimulated by rising atmospheric carbon dioxide levels.