In a recent post on the Earthbound Report, Jeremy Williams says that 2020 may have “marked a strange symbolic moment: when the weight of the human world overtook the weight of the natural living world.” [*] The post begins:
“A paper in the Nature journal [*] has attempted to quantify and compare these two measurements. On one side is the weight of all the world’s living things, the forests and the plants and animals, which they call global living biomass. This has been calculated as around 1.1 teratonnes, which is a hefty word that I don’t get to use often enough. On the other side is the ‘anthropogenic mass’, which is the stuff created by human activity. The biggest component is concrete, and then aggregates such as sand and gravel. Metals, wood, glass and plastic are also included. The total weight of human resources has been doubling every twenty years, and 2020 is the year that they weigh the same as the natural living world.”
Williams says that this is more symbolic than consequential “this doesn’t represent a tipping point of consequence”. What it does do, he says, is “reinforce the impact that humanity – especially the overdeveloped wealthy countries of the global North – are having on the planet. Nature is being reshaped according to human priorities.” A commentator adds: “To me this graph is highly significant in bringing home what exponential growth implies in this area”.
If you look at the paper itself, the research throws up stark comparisons; eg,
– total mass of all the world’s animals = 4 gigatonnes – total mass of all the plastic in the world = 8 gigatonnes.
– total mass of all the world’s trees and shrubs = 900 gigatonnes – total mass of all the world’s buildings and infrastructure = 1100 gigatonnes
And there is useful detail on humanities’ effects on the natural world. For example:
“While the mass of humans is only about 0.01% of global biomass, our civilization had already had a substantial and diverse impact on it by 3,000 years ago. Since the first agricultural revolution, humanity has roughly halved the mass of plants, from approximately two teratonnes (Tt, units of 1012 tonne; where estimates are on a dry-mass basis) down to the current value of approximately 1 Tt. While modern agriculture utilizes an increasing land area for growing crops, the total mass of domesticated crops (about 0.01 Tt) is vastly outweighed by the loss of plant mass resulting from deforestation, forest management and other land-use changes. These trends in global biomass have affected the carbon cycle and human health. Additional human actions, including livestock husbandry, hunting and overfishing, have also strongly affected the masses of various other taxa. A recent survey of Earth’s remaining living biomass has found that, on a mass basis, plants constitute the vast majority (about 90%), followed by bacteria, fungi, archaea, protists, and animals.”
Elhacham, E., Ben-Uri, L., Grozovski, J. et al. Global human-made mass exceeds all living biomass. Nature 588, 442–444 (2020). https://doi.org/10.1038/s41586-020-3010-5
Williams uses “weight” throughout his post whereas the Nature paper properly uses “mass”. The use of weight by Williams, however, is clearly intentional in the (equally correct) sense that we are exerting weight (a force) on the non-human part of the world. His blog won the Green and Eco category at the UK Blog Awards in 2016. Veulio named it the leading green blog in Britain in 2018.