What you are seeing

Every sphere on this page answers the same simple question: if you gathered every gram of something on Earth into a single ball, how big would that ball be? The answers are drawn at true scale, so that water, biomass, and every human-made object can be compared at a glance.

Here in the Local view, those spheres hover above a real patch of Earth's surface instead of next to the whole planet. That way the small ones — a city's worth of humans, all wild land mammals, a year's worth of plastic — stop being invisible specks and become tangible objects. For the planet-scale comparisons (oceans, atmosphere, all ice), open the Global view.

The geometry of volume

A sphere's volume grows with the cube of its radius: V = ⁴⁄₃ π r³, and the radius grows with the cube root of the volume: r = ³√(3V ∕ 4π). The consequence is striking: a sphere with 1,000× more volume is only 10× wider. Doubling the size of a ball means containing eight times more — our eyes do not naturally think this way, and that is part of why these spheres surprise.

• Total water ≈ Ocean — oceans are 96.5% of all water; a 3.5% surplus barely widens the sphere.
• Freshwater (all) ≈ Ice — about 69% of fresh water is frozen in ice and snow.
• Water vapor is tiny — just 0.001% of all water — yet it drives every storm, cloud and rainfall on Earth.

The "Air" sphere

The atmosphere is surprisingly heavy — about 5.15 × 10¹⁸ kg of air. But most of that mass is extremely thin: at 30 km up, the air is already less than one percent of its sea-level density. If every molecule were squeezed down to the density you breathe right now (about 1.225 kg/m³), all that air would collapse into a sphere of radius ≈1,000 km — bigger than the sphere of Total Water, yet still smaller than Earth's Moon.

Dry vs. wet biomass

Scientists measure life in several different units, so we convert everything through one shared chain:

• Carbon (Gt C) — the gold-standard metric from Bar-On et al. (2018, PNAS). Every kingdom of life is first reported by its carbon content. Carbon is about half of dry plant matter, a little less than half for microbes and animals.
• Dry mass = Carbon × 2.25 — the weight of a living thing with every drop of tissue water removed. Global ≈ 1.1 Tt.
• Wet (fresh) mass = Dry × tissue-water factor (plants ×2, microbes ×3.3, animals ×3) — what a living organism actually weighs, water and all. Global ≈ 2.2 Tt.

At water density one gigatonne of biomass becomes one cubic kilometre, so spheres are directly size-comparable across kingdoms. Use the Dry / Wet toggle in the sphere panel to switch between the two.

The Anthropocene crossover

Around 2020 — give or take six years — the total mass of all human-made things still in use (concrete, aggregates, bricks, asphalt, metals, plastic, wood, glass) equalled the dry mass of every living thing on Earth. Our built world now rivals the weight of the biosphere itself. The stock is doubling roughly every twenty years, a pace no natural biological process can match. On a wet-biomass basis the crossover came earlier, around 2013.

Each anthromass sphere is sized by the real-world bulk density of the material — how tightly it packs in the world. Concrete (2.4 t/m³) and metals (7.8 t/m³) pack small; aggregates (1.6 t/m³) and wood (0.6 t/m³) spread wide.

Scale and the invisible

Humanity in total is about 420 million tonnes of wet mass — a sphere just 0.31 km across, next to Earth's 6,371 km radius. Wild land mammals form an even smaller droplet, roughly 170 m in radius. At planet scale these are imperceptible. Here in the Local view, that 0.31 km sphere becomes a tangible object — a beach ball suspended above a Himalayan ridge, or a boulder next to a city block — where the scale of our presence on Earth finally comes into view.

Annual flows & Cumulative impact

Two groups extend the comparison beyond standing stocks — what exists right now — to what moves, and what accumulates. Annual flows compress one year of CO₂, methane, fixed nitrogen, concrete, steel, plastic, sediment, fish and water withdrawal into a single sphere. Gases are shown at their liquid or solid density (CO₂ as dry ice, methane as liquefied natural gas, ammonia as liquid ammonia) so they are directly comparable to the solid materials.

Cumulative impact does the same for all-time totals: every gram of CO₂ emitted since 1750, every grain of topsoil mobilised by agriculture since the Neolithic, every cubic kilometre of polar ice lost since NASA's GRACE satellites began weighing the caps in 2002, every plastic pellet produced between 1950 and 2015, every whale caught by 20th-century industrial whaling. Together, the two groups translate humanity's footprint into the same visual grammar as oceans and air.

The Local view

This view renders a 3D slab of Earth's surface — typically 30–60 km across. Satellite imagery from Esri World Imagery (Maxar, Earthstar Geographics) is draped onto a real digital elevation model from AWS Open Data Terrain Tiles (Mapzen/Terrarium): a grid of height readings that turns flat pixels into genuine topography. Vertical relief is exaggerated by a factor of two so that mountain ranges feel like mountain ranges. The layered wall behind the slab is a stylised stratigraphic profile — decorative, not a specific local geology.

Limitations

These spheres are illustrative scale comparisons, not geographic distributions. The "Air" sphere is a thought experiment: the real atmosphere is highly rarefied, with three-quarters of its mass sitting within the lowest 11 km, and could never actually collapse to sea-level density. Biomass is an instantaneous standing stock, not a flux — it measures how much life is alive right now, not how fast carbon and nutrients move through it. Human-made mass is the in-use stock around 2020, not cumulative historical extraction; demolished buildings and industrial waste are tracked separately in the Cumulative-impact group. Annual-flow spheres compress gases to solid or liquid form (CO₂ as dry ice, CH₄ as LNG, N₂O as liquid, NH₃ as liquid ammonia); real atmospheric CO₂ at normal pressure would be around 800 times larger than the sphere shown. Several large spheres (water, air, freshwater, cumulative erosion, cumulative ice loss) exceed the Local slab and are hidden here — open the Global view to see them at planetary scale.

Sources & provenance

• Water inventory — USGS Water Science School / Gleick 1996. USGS page.
• Atmosphere mass — Trenberth & Smith (2005). J. Climate 18, 864–875. doi:10.1175/JCLI-3299.1
• Biomass (all kingdoms) — Bar-On, Phillips, Milo (2018). PNAS 115(25): 6506–6511. doi:10.1073/pnas.1711842115
• Wild mammals (present-day) — Greenspoon et al. (2023). PNAS 120(10): e2204892120. doi:10.1073/pnas.2204892120
• Mammals since 1850 + human biomass update — Greenspoon et al. (2025). Nature Communications 16:8338. doi:10.1038/s41467-025-63888-5
• Human-made mass (2020 stock) — Elhacham et al. (2020). Nature 588, 442–444. doi:10.1038/s41586-020-3010-5
• Material stocks & flows — Krausmann et al. (2017). PNAS 114:1880–1885. doi:10.1073/pnas.1613773114
• CO₂ emissions — Friedlingstein et al. (2019). ESSD 11:1783. doi:10.5194/essd-11-1783-2019
• Methane budget — Saunois et al. (2020). ESSD 12:1561. doi:10.5194/essd-12-1561-2020
• N₂O budget — Tian et al. (2020). Nature 586:248. doi:10.1038/s41586-020-2780-0
• Anthropogenic sediment — Cooper et al. (2018). Anthropocene Review 5:222. doi:10.1177/2053019618800234
• Cumulative soil erosion — Wang, Van Oost & Govers (2019). The Holocene. doi:10.1177/0959683618810401
• Water withdrawal — Qin et al. (2019). Nature Sustainability 2:515. doi:10.1038/s41893-019-0294-2
• Plastic — Geyer, Jambeck & Law (2017). Science Advances 3:e1700782. doi:10.1126/sciadv.1700782
• Dam-fragmented rivers — Grill et al. (2019). Nature 569:215. doi:10.1038/s41586-019-1111-9
• Reservoir capacity — FAO AQUASTAT. aquastat.fao.org
• Polar ice loss — Wiese et al. (2019). NASA JPL GRACE/GRACE-FO mascons. PO.DAAC
• Industrial whaling — Rocha, Clapham & Ivashchenko (2014). Marine Fisheries Review 76(4):37. spo.nmfs.noaa.gov
• Database / anthology — Chure et al. (2022). Patterns 3:100552. doi:10.1016/j.patter.2022.100552 · anthroponumbers.org

Educational purpose

Sfera is a non-commercial educational project by GLOBAÏA, a non-profit working to make planetary-scale scientific knowledge accessible to a general audience. Every value on this page is drawn from peer-reviewed literature or open-access databases, all of which are listed above. The visualisation and its captions are intended for science communication and education — they are not a primary research source, and should not be cited in place of the underlying papers.

Credits

Designed, built and maintained by GLOBAÏA. Source code and data in the repo; corrections and contributions welcome.

Suggested citation

GLOBAÏA (2026). Sfera: Planetary-scale comparison spheres [interactive visualisation]. globaia.org/sfera/. Accessed .