Homo sapiens – 287 million tonnes
Domesticated Livestock – 700 million tonnes
Wild animals –
around 200,000 wolves vs 400 million domesticated dogs
250,000 chimps vs 7 billion humans
Vaclav Smil website
. . . where he estimates that there was 620 Mt of domesticated zoomass on the planet in 2000, and “wild terrestrial mammals” are below 40 Mt.
The notion of homo sapiens somehow being marginalised by concern for nature is not supported by the science – human beings have colonised every available niche on the planet we possibly can. Research by Professor Vaclav Smil from the University of Manitoba in Canada shows that as a percentage of mammalian zoomass, human beings and our domesticated mammalian animals (for food, beasts of burden and as pets) have gone from <0.1% 10,000 years ago, to 10-12% at the start of the industrial revolution to between 96-98% today. Human beings can and will expand to fill every available ecological niche within reach, and has done so at the expense of other species.
At some time in recent pre-history, there were fewer than 100,000 humans, hunter gatherers all, while the rest of mammal diversity was wild. Then humans domesticated plants and animals, and together they came to dominate the landscape in a very short time.
Background to the calculations: Canadian economist and mathematician Vaclav Smil has calculated the best estimates for the biomass of terrestrial mammals on planet earth, dividing them into human, livestock and remaining wild mammals, and the picture is pretty stark.
Sarah C Walpole, David Prieto-Merino, Phil Edwards, John Cleland, Gretchen Stevens and Ian Roberts
The energy requirement of species at each trophic level in an ecological pyramid is a function of the number of organisms and their average mass. Regarding human populations, although considerable attention is given to estimating the number of people, much less is given to estimating average mass, despite evidence that average body mass is increasing. We estimate global human biomass, its distribution by region and the proportion of biomass due to overweight and obesity.
For each country we used data on body mass index (BMI) and height distribution to estimate average adult body mass. We calculated total biomass as the product of population size and average body mass. We estimated the percentage of the population that is overweight (BMI > 25) and obese (BMI > 30) and the biomass due to overweight and obesity.
In 2005, global adult human biomass was approximately 287 million tonnes, of which 15 million tonnes were due to overweight (BMI > 25), a mass equivalent to that of 242 million people of average body mass (5% of global human biomass). Biomass due to obesity was 3.5 million tonnes, the mass equivalent of 56 million people of average body mass (1.2% of human biomass). North America has 6% of the world population but 34% of biomass due to obesity. Asia has 61% of the world population but 13% of biomass due to obesity. One tonne of human biomass corresponds to approximately 12 adults in North America and 17 adults in Asia. If all countries had the BMI distribution of the USA, the increase in human biomass of 58 million tonnes would be equivalent in mass to an extra 935 million people of average body mass, and have energy requirements equivalent to that of 473 million adults.
Increasing population fatness could have the same implications for world food energy demands as an extra half a billion people living on the earth.
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