Exploring the distribution of biomass across our planet and humanity's profound impact on Earth's living matter
Imagine if we could gather every living thing on Earth—every elephant, every tree, every microscopic bacterium—and place them on a gigantic scale. Then, imagine placing all the concrete, plastic, and other materials humans have created on another scale. Astonishingly, in 2020, the human-made scale outweighed all living matter on our planet2 . This startling fact reveals the profound impact humanity has had on Earth's natural composition.
Understanding how biomass is distributed across our planet is not merely an academic exercise—it provides crucial insights into the structure and dynamics of the biosphere that sustains us all. Through groundbreaking scientific research, we can now quantify this distribution, uncovering patterns that highlight both nature's incredible diversity and humanity's growing influence.
Scientists define biomass as the total mass of living organisms, typically measured by their carbon content because carbon is the fundamental building block of all biological molecules2 . This approach allows for meaningful comparisons between vastly different life forms, from massive whales to microscopic bacteria.
Recent scientific efforts have culminated in the first comprehensive census of Earth's biomass, revealing a planet dominated by unexpected organisms and full of surprising imbalances. This article will explore how scientists calculate the weight of life, what these calculations reveal about our planet, and how human activity is reshaping Earth's living landscape.
How does one actually go about weighing all life on Earth? The team led by Dr. Yinon Bar-On and Professor Ron Milo from the Weizmann Institute of Science approached this monumental task with a systematic strategy that combined thousands of local studies with global environmental data4 . Their methodology, conducted in 2018, represents the most comprehensive attempt to quantify global biomass to date.
Researchers conducted an extensive review of scientific literature to gather local biomass measurements from around the world.
They correlated these local measurements with environmental parameters known at a global scale, such as temperature and primary productivity.
Using these correlations, they extrapolated biomass estimates across the entire planet.
Finally, they integrated data for each taxonomic group to arrive at a global total.
This approach inevitably comes with uncertainties, particularly for organisms that are difficult to measure, such as deep-sea bacteria or tree roots in tropical forests2 4 .
For bacteria, the estimate may be off by a factor of ten, meaning the actual biomass could be anywhere from 7 to 700 gigatons of carbon4 . Nevertheless, by transparently acknowledging these limitations and using consistent methodology, the research provides our clearest picture yet of Earth's biomass distribution.
The results of the global biomass census reveal a planet dominated by the plant kingdom, which accounts for approximately 450 gigatons of carbon—roughly 80% of all biomass6 . This plant predominance is visually evident in regions like the Amazon rainforest, but the data reveals surprising patterns across all kingdoms of life.
The animal kingdom, despite its incredible diversity and central place in human perception of nature, represents just 0.4% of Earth's biomass6 . Within this already small slice, humans and their livestock dominate even further.
The distribution of biomass across different environments reveals another striking pattern: terrestrial biomass is about two orders of magnitude higher than marine biomass6 . This is particularly surprising given that oceans cover approximately 70% of Earth's surface.
The total marine biomass is estimated at only 6 gigatons of carbon6 . Within this marine environment, the biomass pyramid appears inverted in some cases, with more consumers than producers, challenging conventional ecological models6 .
The influence of humanity on Earth's biomass extends far beyond our direct physical presence. In a follow-up study to their original biomass census, the same research group calculated the mass of all anthropogenic material—everything humans have produced or processed2 . Their findings revealed a tectonic shift in the composition of Earth's surface: by 2020, the mass of human-made materials had surpassed the total mass of all living biomass2 .
This human-made mass consists largely of construction materials, with concrete alone accounting for over 40% of the total, followed by bricks, asphalt, and metals like steel2 .
The accumulation of anthropogenic mass is not only substantial but accelerating. The total reached approximately 1,400 gigatons in 2024, with this mass doubling roughly every 20 years2 .
This transformation comes at a cost to natural biomass. As the researchers note, "Often, human development does not coexist with nature, but rather comes at its expense"2 . The conversion of natural ecosystems to agriculture, industry, and infrastructure represents both a direct reduction of biomass and a threat to the ecosystem services—clean water, breathable air, flood protection—that make Earth habitable.
The groundbreaking study behind these revelations, led by Dr. Yinon Bar-On and Professor Ron Milo at the Weizmann Institute of Science, employed a meticulous methodology that combined local sampling with global modeling to estimate the biomass of all major taxonomic groups4 .
Exhaustive survey of scientific articles with local biomass measurements
Identifying key environmental factors influencing biomass distribution
Creating global distribution maps for each taxonomic group
Quantifying uncertainties and integrating data across the planet
This methodology was particularly robust for plants, where researchers could draw on multiple independent data sources including the Forest Resources Assessment by the United Nations Food and Agriculture Organization and remote sensing data that provides high coverage of plant biomass measurements4 .
For other groups, like terrestrial arthropods or deep-sea microbes, the estimates necessarily came with greater uncertainty due to sampling limitations.
The results revealed not just the total biomass but striking patterns in its distribution. Perhaps most surprisingly, terrestrial biomass was found to be about two orders of magnitude higher than marine biomass, with plants dominating the global picture at approximately 450 gigatons of carbon6 .
Understanding how scientists measure global biomass helps appreciate both the power and limitations of these estimates. Researchers employ a diverse array of tools and methods, each suited to different components of Earth's biomass.
Application: Large-scale vegetation mapping
Provides high-resolution, global data on plant biomass
Application: Terrestrial plant assessment
Uses standardized methodology across countries
Application: Microbial biomass estimation
Allows differentiation between autotrophic and heterotrophic organisms
Application: Biomass valorization
Reduces mineral content for more accurate energy content measurement
Application: Process optimization
Statistically determines optimal experimental conditions
Application: Forest biomass measurement
Measures tree mass even in dense forests
Recent technological advances are rapidly improving our ability to measure biomass accurately. The European Space Agency's Biomass mission, launched in April 2025, uses penetrating radar to measure tree mass even in dense forests that were previously difficult to survey1 2 . This satellite, along with other systems like GEDI (mounted on the International Space Station) and JAXA's ALOS-2, provides increasingly high-resolution three-dimensional data that enhances traditional ground-based measurements2 .
The census of Earth's biomass is not a static picture but a dynamic field of research. As measurement technologies improve, our understanding becomes more refined. The recent launch of specialized biomass monitoring satellites promises to substantially improve terrestrial biomass models, particularly in hard-to-survey regions like tropical forests2 .
These technological advances are complemented by machine-learning methods that can estimate tree mass at virtually every point on Earth2 .
This research carries profound implications for addressing global environmental challenges. As we better understand the distribution of biomass, we can more accurately model carbon cycles and climate change impacts.
The European Space Agency's Climate Change Initiative has already developed increasingly sophisticated above-ground biomass maps that track how forest carbon stocks have changed over the past two decades1 .
Perhaps most importantly, this research provides a crucial baseline against which to measure future changes, both natural and human-driven. As we continue to reshape our planet's living landscape, understanding the fundamental distribution of biomass becomes essential for making informed decisions that balance human needs with the preservation of the ecological systems that sustain us.
The story of Earth's biomass is still being written, and humanity has increasingly become its author. The choices we make today—about how we use resources, manage ecosystems, and value nature—will determine the next chapter in this ongoing planetary saga.