Anthropocene: Immediately, man-made supplies weigh as a lot as all dwelling biomass, say scientists


Jan Zalasiewicz, University of Leicester and Mark Williams, University of Leicester

Our shortcomings have always driven us back even among our distant ancestors during the last Ice Age. We didn’t have the speed and strength to hunt down large prey, sharp teeth and claws to tear flesh, and improvised spears, flint knives and scrapers. Since we didn’t have thick fur, we took other animals’ fur. As the ice receded, we developed more means of survival and comfort – stone dwellings, plows, wheeled vehicles. All these inventions made it possible to wrest small oases of civilization from a natural wilderness that seemed endless.

The idea of ​​a natural world dwarfing humanity and its creations has long persisted in modern times – only to have recently met with concerns that the climate is changing and species are dying as a result of our actions. How could that be when we are so small and nature is so big?

A new nature study by a team of scientists at the Weizman Institute in Israel confirms this perspective. Our constructions have now – creepy indeed, just this year – attained the same mass as those of all living organisms on earth. Human enterprise is also growing rapidly, while nature continues to shrink. The science fiction scenario of a technical planet is already there.

It seems like an easy comparison, yet it is devilishly difficult in practice. However, this team is experienced in dealing with such impossible challenges. A few years ago they worked out the first part of the equation, the mass of all life on earth – including all fish in the ocean, microbes in the ground, trees on land, birds in the air, and more. The earth’s biosphere now weighs a little less than 1.2 trillion tons (dry matter, excluding water), with trees on land making up the majority of it. It was about twice as much before people started clearing forests – and it’s still falling.

Old General Sherman Tree in Sequoia National Park, California. This tree is the largest known living single family tree on earth.

Now the team has dealt with the statistics of industrial production and mass flows of all kinds and has reconstructed the growth of the so-called “anthropogenic mass” since the beginning of the 20th century. These are all things we build – houses, cars, roads, planes, and countless other things. The pattern they found was strikingly different. The material we build amounted to about 35 billion tons in 1900 and increased to about double by the middle of the 20th century. Then, that post-World War II prosperity surge, known as the Great Acceleration, our material rose many times over to just over half a trillion tons by the end of the century. In the last 20 years it has doubled again to correspond to the mass of all living things this year. In the years to come, the living world will far outweigh it – tripling by 2040 if current trends persist.

Most of the weight is in concrete.

What kind of stuff is that we make? It is now of an extraordinary and exploding variety. The number of “technospecies” far exceeds the estimated 9 million biological species on earth, and their count even exceeds the vast computing power of this team. But our stuff can be broken down into ingredients, of which concrete and aggregates make up a gigantic proportion – about four fifths. Then there are bricks, asphalt and metals. On this scale, plastics are a minor ingredient – and yet their mass is still greater than that of all animals on earth.

It is an insightful, careful study and it is clear what the measurements include and exclude. This includes, for example, neither the rock leveled and landscaped as the foundation for our constructions and the earth, nor all the waste rock that is produced when the constituents are broken down: Currently, almost a third of a trillion tons of this material is moved every year. Add material to the earth that we otherwise use and abuse to plow farmland and build up sediment behind dams, and people have cumulatively used and discarded about 30 trillion tons of the earth’s various resources.

Regardless of how you cut the pie, the team’s final point in their groundbreaking study holds true and matches that of another recent analysis we both worked on. Since the mid-20th century, the earth has been on a new, human-powered path that abandons the stable conditions of the Holocene and enters the uncertain and rapidly changing new world of the Anthropocene. The weight of the evidence here seems indisputable.

Jan Zalasiewicz, Professor of Paleobiology, University of Leicester and Mark Williams, Professor of Paleobiology, University of Leicester

This article is republished by The Conversation under a Creative Commons license. Read the original article.

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