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January 23, 2011

Technomass and Biomass

By Joseph Friedlander

One of my great interests for many years has been the quantities and ratio of the natural biological world (excepting geology) to the works of Man. In other words, how much Biomass vs Technomass. I recently read a paper by Richard Cathcart that piqued my old curiosity so here are the results...

To use the phrase Biomass vs Technomass begs definitions of each. Regarding biomass estimates, the deep biosphere hypothesized by Dr. Thomas Gold almost certainly exists at some scale, but because it by definition is unknown it is not counted. Only known life is included.



Technomass could be defined on several levels-- the most obvious is manufactured technomass (including cement, concrete) but excluding structural fill, bermed earth, and things that are just moved natural substances rather than processed. An even more general meaning of moved natural substances might be the amount of plowed earth thrown aside a few inches or decimeters in the course of routine farming. (There are many other even more classes of being 'touched' by man but not especially of interest to the technomass question, for example sewage etc that are simply part of natural flows in the biosphere.)

If we Google the search term “yearly biological productivity of earth billion tons”
on biomass - the results suggest 140 gigatons of biological growth including bacteria yearly--- and a living stockpile of 560 billion tons of carbon

The composition of the human body is about ~18% carbon for a human, which could be applied as an estimate to other biological material

so that implies about 3100 billion tons of living stuff (140 gigatons grown annually) for an average 'lifespan' (inventory turnover time of living to dead) of 22 years which is surprising, but I suppose that includes trees and theoretically undying single cell populations too...

We lose around 75 billion tons of eroded soil a year--(not only from farming) and move perhaps 20-100 times that in plowing.

(1.5-2 billion hectares (15-20 million square kilometers), moving the top 10 centimeters of 1 billion hectares at a soil density of 1.33 is 1.33 trillion tons of dirt moved a few centimeters yearly.

This is an astonishing mass of soil moved-- each decade about the mass of Phobos, moon of Mars--10 trillion tons. As Phobos constitutes a volume of about 5600 cubic kilometers, it is sobering to realize that the life-giving topsoil that grows our crops is so thin and so small in volume.

Moving from the merely moved topsoil to actively dug substances, we almost certainly move more than 35 billion tons of rock and ore per year (and assuming a third of that is rock and not loose breakable material, using the rule of 1:1000 for explosives to break the rock we probably use about 10 million tons of industrial explosives http://en.wikipedia.org/wiki/ANFO yearly worldwide. We mine 7 billion tons of coal, two billion tons of iron ore, (over a billion tons of iron yearly) over 2.2 billion tons of cement (at a 4:1 mixture ratio with fine and coarse aggregate , making ~9 billion tons of concrete to get which would be four cubic kilometers of concrete!), probably a hundred million tons of dimension stone for facing, and probably around 20 billion tons of sand, gravel, fill of all kinds, and rock for use in construction.

About that concrete-- since that is the primary material of which the modern world is made, if we say that in the sum total of history we have produced perhaps the equivalent of 17 years current production

(Far less in reality over far more years, but if you go back further than the 1920s production is very low) ~150 gigatons of concrete (actual structure -- this is plausible because of the embankments you see on the highway, hundreds of tons of dirt held back by tens of tons of concrete-- the same on a larger scale for dams---)

We can estimate the maximum area that could have been paved over if all 150 billion tons of concrete had been used 10 cm deep. Each year's production nowadays, if 1/10th meter thick, 4 cubic kilometers can pave over 40000 km2 as a simple parking lot, or if in buildings wall to wall --say 10-15000 km2 (assuming floor, ceiling, walls use equal amounts. Multiplying these numbers by 17 years production which in our assumption is the equivalent of all the concrete ever made, we see that a total of 680000 square kilometers could have been paved over 1/10th meter thick, or 255000 square kilometers of buildings made. (Remember, these are the actual road surfaces or house areas, not the green spaces separating them. Even in a fairly dense city expanse as much as ¾ the area can be non-paved.)

In conclusion, we have moved around dirt and rock about like the biomass of the Earth! (3100 billion tons of living stuff ) Average biological productivity is around 140 billion tons of new growth, about 4 times what we mine as ore or directly usable materials (as opposed to mere embankments and landscaping and plowing). With a few more economic doublings, the next hundred years should see technomass finally eclipse biomass-- not through lessening of the latter, but through growth of the former.


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