A quantitative prespective
on the biosphere in the Anthropocene
By measuring the mass of living things (i.e. biomass) at the global scale, we can uncover profound shifts in the balance of nature, with humanity becoming an increasingly dominant force shaping the natural world around us and highlight the growing urgency of conservation efforts.
Publications
The Biomass Distribution on Earth
Bar-On et al., PNAS, 2018
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The composition of the biosphere is a fundamental question in biology, yet a global quantitative account of the biomass of each taxon is still lacking. We assembled a census of the biomass of all kingdoms of life.
Global human-made mass
exceeds all living biomass
Elhacham et al., Nature, 2020
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​We find that Earth is exactly at a crossover point; in the year 2020 (± 6), the anthropogenic mass, which has recently doubled roughly every 20 years, will surpass all global living biomass.
The global biomass of
wild mammals
Greenspoon et al., PNAS, 2023
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We quantified absolute mammalian biomass and its distribution across different groups, and found that wild mammals comprise only 5% of mammalian biomass globally.
The global biomass and number
of terrestrial arthropods
Rosenberg et al., Science Advances, 2023
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Insects and other arthropods are central to terrestrial ecosystems. We estimate the combined dry biomass of all terrestrial arthropods at ≈300 Mt, similar to the mass of humanity and its livestock.
The global biomass of mammals
since 1850
Greenspoon et al., Nature Communications, 2025
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Since 1850, the combined biomass of wild land and marine mammals has plummeted by about 70 percent – from about 200 million tonnes to about 60 million tonnes.
Human biomass movement
exceeds the biomass movement
of all land animals combined
Rosenberg et al., Nature Ecology & Evolution, 2025
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The combined biomass movement of all wild birds, land arthropods and wild land mammals is about 40 times smaller than all the biomass movement of humans.
Click the images to view the published paper.
See full list of publications by the Milo Lab here
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Biomass units
Biomass, defined as the weight of living organisms, serves as a metric that allows comparison between groups of species differing in mass by many orders of magnitude (e.g. elephants compared to viruses).
Biomass can also be applied at different geographical scales and regionally integrated to give an overall estimate at the global level, helping to visualize the holistic state of wildlife. Biomass is correlated with energy and mass flows in food webs, shows the amount of carbon stored in different organisms, and can hint at the scale by which a species can affect its surrounding ecosystem.
Biomass can be used as a metric to complement other biodiversity metrics, such as species richness (i.e. number of species).
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Within biomass, there are different units commonly used:​​​​​​​​
​Wet mass refers to the mass of all components in an organism, including the water present, which typically dominates total mass. Wet mass is an intuitive metric, especially for humans and other animals. ​
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Dry mass refers to the mass of all components in an organism, after dehydration. and can be a more appropriate metric in some cases. For example, in some groups of species, such as plants, water content fluctuates over time depending on the season and levels of precipitation. ​
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Carbon mass refers to the total weight of organic carbon stored within the living matter.