[{"id":"population","label":"World population","unit":"","format":"compact","interpolation":"linear","accent":"#5ad1a5","note":"Humans and their ancestors only - zero for most of Earth history.","anchors":[{"year":-540000000,"value":0},{"year":-3000000,"value":0},{"year":-300000,"value":500000},{"year":-70000,"value":50000},{"year":-12000,"value":4000000},{"year":-10000,"value":4500000},{"year":-9000,"value":5690000},{"year":-8000,"value":7310000},{"year":-7000,"value":9650000},{"year":-6000,"value":13300000},{"year":-5000,"value":19200000},{"year":-4000,"value":28900000},{"year":-3000,"value":44600000},{"year":-2000,"value":72700000},{"year":-1000,"value":111000000},{"year":1,"value":232000000},{"year":100,"value":237000000},{"year":200,"value":241000000},{"year":300,"value":228000000},{"year":400,"value":242000000},{"year":500,"value":253000000},{"year":600,"value":272000000},{"year":700,"value":278000000},{"year":800,"value":286000000},{"year":900,"value":311000000},{"year":1000,"value":323000000},{"year":1100,"value":398000000},{"year":1200,"value":445000000},{"year":1300,"value":456000000},{"year":1400,"value":442000000},{"year":1500,"value":503000000},{"year":1600,"value":516000000},{"year":1700,"value":595000000},{"year":1710,"value":618000000},{"year":1720,"value":648000000},{"year":1730,"value":671000000},{"year":1740,"value":702000000},{"year":1750,"value":753000000},{"year":1760,"value":788000000},{"year":1770,"value":828000000},{"year":1780,"value":901000000},{"year":1790,"value":942000000},{"year":1800,"value":990000000},{"year":1850,"value":1260000000},{"year":1900,"value":1650000000},{"year":1901,"value":1659000000},{"year":1902,"value":1668000000},{"year":1903,"value":1678000000},{"year":1904,"value":1688000000},{"year":1905,"value":1698000000},{"year":1906,"value":1709000000},{"year":1907,"value":1719000000},{"year":1908,"value":1729000000},{"year":1909,"value":1740000000},{"year":1910,"value":1750000000},{"year":1927,"value":2000000000},{"year":1950,"value":2536000000},{"year":1975,"value":4070000000},{"year":1987,"value":5000000000},{"year":2000,"value":6143000000},{"year":2011,"value":7000000000},{"year":2022,"value":7950000000},{"year":2024,"value":8120000000}],"sources":[{"label":"Our World in Data; HYDE 3.3","url":"https://ourworldindata.org/grapher/population"},{"label":"Klein Goldewijk, K., Beusen, A., Doelman, J. & Stehfest, E. (2017), 'Anthropogenic land use estimates for the Holocene - HYDE 3.2', Earth System Science Data 9, 927-953 - the methodology and native time-step design behind the HYDE series","url":"https://essd.copernicus.org/articles/9/927/2017/"},{"label":"U.S. Census Bureau, 'Historical Estimates of World Population' - the standard side-by-side compilation of Biraben (1980), Durand, Haub, McEvedy & Jones (1978), Thomlinson, Clark and the UN; used here only to establish the spread between scholars, not to source any anchor value","url":"https://www.census.gov/data/tables/time-series/demo/international-programs/historical-est-worldpop.html"}],"group":"Humanity","order":10,"inSnapshot":true,"headline":1,"chipLabel":"Population","maxHonestGap":250,"minMeaningful":1},{"id":"gdp","label":"Gross world product","unit":"$tn","format":"decimal1","interpolation":"smooth","accent":"#d9a441","note":"Total world economic output, trillions of 2011 int-$. Flat for most of history; it explodes after 1800.","naBefore":-10000,"anchors":[{"year":-10000,"value":0},{"year":1,"value":0.2},{"year":1000,"value":0.2},{"year":1500,"value":0.4},{"year":1700,"value":0.6},{"year":1820,"value":1.2},{"year":1870,"value":2},{"year":1900,"value":3.4},{"year":1901,"value":3.5},{"year":1902,"value":3.6},{"year":1903,"value":3.6},{"year":1904,"value":3.7},{"year":1905,"value":3.8},{"year":1906,"value":3.9},{"year":1907,"value":3.9},{"year":1908,"value":3.9},{"year":1909,"value":4},{"year":1910,"value":4.1},{"year":1940,"value":7.8},{"year":1950,"value":9.3},{"year":1970,"value":22.5},{"year":1990,"value":50.9},{"year":2000,"value":63},{"year":2010,"value":95},{"year":2018,"value":121},{"year":2024,"value":130}],"sources":[{"label":"Our World in Data — Global GDP over the long run","url":"https://ourworldindata.org/grapher/global-gdp-over-the-long-run"},{"label":"Maddison Project Database 2020","url":"https://www.rug.nl/ggdc/historicaldevelopment/maddison/releases/maddison-project-database-2020"}],"group":"Humanity","order":12,"tileLabel":"World product"},{"id":"emissions","label":"Human CO₂ emissions","unit":"Gt/yr","format":"decimal1","interpolation":"smooth","accent":"#c65b3a","note":"Fossil-fuel and industry CO₂ released each year (land-use change not included). Essentially zero before ~1750; about 38.6 Gt in 2024.","naBefore":1700,"anchors":[{"year":1750,"value":0},{"year":1800,"value":0},{"year":1850,"value":0.2},{"year":1875,"value":0.7},{"year":1900,"value":2},{"year":1925,"value":3.7},{"year":1950,"value":5.9},{"year":1960,"value":9.4},{"year":1970,"value":14.9},{"year":1980,"value":19.4},{"year":1990,"value":22.7},{"year":2000,"value":25.5},{"year":2010,"value":33.3},{"year":2019,"value":37.1},{"year":2024,"value":38.6}],"sources":[{"label":"Our World in Data — CO₂ emissions","url":"https://ourworldindata.org/co2-emissions"},{"label":"Our World in Data — Annual CO₂ emissions, World (Global Carbon Budget 2025)","url":"https://ourworldindata.org/grapher/annual-co2-emissions-per-country"}],"group":"Humanity","order":15,"tileLabel":"CO₂ emissions"},{"id":"urbanization","label":"Urbanization","unit":"%","format":"integer","interpolation":"smooth","accent":"#c98b5a","note":"Share of humans living in towns and cities. Under ~10% for all of history until the 1800s; the world passed 50% urban around 2008.","naBefore":-3500,"anchors":[{"year":-3000,"value":0.3},{"year":-1000,"value":0.7},{"year":1,"value":2.4},{"year":1000,"value":5},{"year":1500,"value":6},{"year":1700,"value":7.1},{"year":1800,"value":8.4},{"year":1900,"value":16.2},{"year":1950,"value":29.1},{"year":2000,"value":46.8},{"year":2010,"value":50.8},{"year":2024,"value":57}],"sources":[{"label":"Our World in Data — Urbanization (population share in urban areas, last 500 years)","url":"https://ourworldindata.org/grapher/urbanization-last-500-years"}],"group":"Humanity","order":13},{"id":"literacy","label":"Literacy","unit":"%","format":"integer","interpolation":"smooth","accent":"#7fa6d0","note":"Share of adults able to read and write. A tiny elite for millennia; mass literacy is barely two centuries old.","naBefore":-3500,"anchors":[{"year":-3000,"value":0},{"year":-500,"value":1},{"year":1,"value":1},{"year":1000,"value":1},{"year":1500,"value":6},{"year":1700,"value":8},{"year":1800,"value":12},{"year":1900,"value":21},{"year":1950,"value":36},{"year":2000,"value":82},{"year":2024,"value":87}],"sources":[{"label":"Our World in Data — Literacy","url":"https://ourworldindata.org/literacy"}],"group":"Humanity","order":14},{"id":"temperature","label":"Avg. global temperature","unit":"°C","format":"decimal1","interpolation":"smooth","accent":"#e8925a","note":"Estimated global mean surface temperature.","anchors":[{"year":-4000000000,"value":30},{"year":-3350000000,"value":30.5},{"year":-2500000000,"value":20},{"year":-2300000000,"value":-50},{"year":-2000000000,"value":15},{"year":-1400000000,"value":15},{"year":-700000000,"value":-50},{"year":-600000000,"value":12},{"year":-540000000,"value":22},{"year":-445000000,"value":13},{"year":-400000000,"value":20},{"year":-340000000,"value":14},{"year":-300000000,"value":13},{"year":-252000000,"value":25},{"year":-200000000,"value":22},{"year":-158000000,"value":23.9},{"year":-120000000,"value":26},{"year":-90000000,"value":28},{"year":-66000000,"value":25},{"year":-50000000,"value":27},{"year":-34000000,"value":18},{"year":-28000000,"value":18.6},{"year":-22000000,"value":19.3},{"year":-15000000,"value":20.7},{"year":-10500000,"value":17.8},{"year":-7000000,"value":17.6},{"year":-4700000,"value":15.2},{"year":-3200000,"value":16.3},{"year":-2600000,"value":14},{"year":-1998000,"value":13.2},{"year":-1348000,"value":12.6},{"year":-918000,"value":7.7},{"year":-780000,"value":12},{"year":-754000,"value":8.1},{"year":-704000,"value":12.9},{"year":-660000,"value":9.1},{"year":-578000,"value":13.2},{"year":-540000,"value":8.7},{"year":-492000,"value":12},{"year":-458000,"value":7.5},{"year":-406000,"value":14.4},{"year":-364000,"value":7.8},{"year":-330000,"value":14.3},{"year":-270000,"value":8.6},{"year":-214000,"value":13.4},{"year":-146000,"value":8.1},{"year":-124000,"value":15.1},{"year":-98000,"value":12.4},{"year":-80000,"value":11.6},{"year":-62000,"value":7.8},{"year":-44000,"value":8.6},{"year":-30000,"value":8.3},{"year":-20000,"value":7.6},{"year":-15000,"value":8.6},{"year":-10050,"value":12.6},{"year":-9550,"value":13},{"year":-9050,"value":13.4},{"year":-8550,"value":13.7},{"year":-8050,"value":13.8},{"year":-7550,"value":13.9},{"year":-7050,"value":13.9},{"year":-6550,"value":14},{"year":-6050,"value":14},{"year":-5550,"value":14.1},{"year":-5050,"value":14.2},{"year":-4550,"value":14.2},{"year":-4050,"value":14.2},{"year":-3550,"value":14.1},{"year":-3050,"value":14.1},{"year":-2550,"value":14},{"year":-2050,"value":14},{"year":-1550,"value":14},{"year":-1050,"value":13.9},{"year":-550,"value":13.9},{"year":-50,"value":13.8},{"year":100,"value":13.7},{"year":200,"value":13.7},{"year":300,"value":13.8},{"year":500,"value":13.8},{"year":540,"value":13.7},{"year":700,"value":13.7},{"year":900,"value":13.7},{"year":1000,"value":13.7},{"year":1100,"value":13.6},{"year":1200,"value":13.6},{"year":1300,"value":13.6},{"year":1400,"value":13.6},{"year":1450,"value":13.5},{"year":1500,"value":13.6},{"year":1550,"value":13.6},{"year":1600,"value":13.5},{"year":1650,"value":13.5},{"year":1700,"value":13.5},{"year":1750,"value":13.5},{"year":1800,"value":13.6},{"year":1900,"value":13.7},{"year":1901,"value":13.6},{"year":1902,"value":13.5},{"year":1903,"value":13.4},{"year":1904,"value":13.3},{"year":1905,"value":13.5},{"year":1906,"value":13.6},{"year":1907,"value":13.4},{"year":1908,"value":13.4},{"year":1909,"value":13.3},{"year":1910,"value":13.4},{"year":1950,"value":13.9},{"year":1990,"value":14.2},{"year":2000,"value":14.4},{"year":2015,"value":14.8},{"year":2024,"value":15.1}],"sources":[{"label":"NASA GISS GISTEMP v4 (annual global anomaly, 1951–1980 base; offset so 1900 = 13.7 °C)","url":"https://data.giss.nasa.gov/gistemp/"},{"label":"Kaufman et al. 2020, Holocene global mean surface temperature, a multi-method reconstruction approach (Sci. Data 7:201) — NOAA temp12k_allmethods_percentiles.csv, 'global_median' column","url":"https://www.ncei.noaa.gov/pub/data/paleo/reconstructions/kaufman2020/temp12k_allmethods_percentiles.csv"},{"label":"PAGES 2k Consortium 2019, Consistent multidecadal variability in global temperature reconstructions and simulations over the Common Era (Nat. Geosci. 12:643) — NOAA Full_ensemble_median_and_95pct_range.txt, '31-year filtered full ensemble median' column","url":"https://www.ncei.noaa.gov/pub/data/paleo/pages2k/neukom2019temp/recons/Full_ensemble_median_and_95pct_range.txt"},{"label":"Tierney et al. 2020, Glacial cooling and climate sensitivity revisited (Nature 584:569) — LGM cooling 6.1 °C (95% CI 6.5–5.7) vs late pre-industrial","url":"https://pubmed.ncbi.nlm.nih.gov/32848226/"},{"label":"Kaufman & Broadman 2023, Revisiting the Holocene global temperature conundrum (Nature 614:425)","url":"https://www.nature.com/articles/s41586-022-05536-w"},{"label":"IPCC AR6 WGI Cross-Chapter Box 2.1 Fig. 1 data (GMST vs 1850–1900, 60 Ma–present), used as '13.7 °C + anomaly': 'Snyder' column for 17 ka–920 ka (glacial maxima and interglacial peaks), 'Hansen' column averaged over ±20–50 kyr for 1.35 Ma–28 Ma","url":"https://dap.ceda.ac.uk/badc/ar6_wg1/data/ch_02/ch2_ccb2_1_1/v20221114/FinalData_CCB2_1_Fig1_DMS.csv"},{"label":"Snyder 2016, Evolution of global temperature over the past two million years (Nature 538:226)","url":"https://www.nature.com/articles/nature19798"},{"label":"Hansen, Sato, Russell & Kharecha 2013, Climate sensitivity, sea level and atmospheric carbon dioxide (Phil. Trans. R. Soc. A 371:20120294)","url":"https://royalsocietypublishing.org/doi/10.1098/rsta.2012.0294"},{"label":"Judd et al. 2024, A 485-million-year history of Earth's surface temperature (Science 385:eadk3705) — PhanDA stage medians (Oxfordian 23.9 °C)","url":"https://github.com/EJJudd/PhanDA/blob/main/5_Outputs/PhanDA_GMSTandCO2_percentiles.csv"},{"label":"Park et al. 2025, Breathing life into the boring billion: 1.4 Ga fluid inclusions reveal a fair climate and oxygenated atmosphere (PNAS 122:e2513030122) — global temperature ~15 °C","url":"https://www.pnas.org/doi/10.1073/pnas.2513030122"},{"label":"Blake, Chang & Lepland 2010, Phosphate oxygen isotopic evidence for a temperate and biologically active Archaean ocean (Nature 464:1029) — 26–35 °C seawater, 3.2–3.5 Ga","url":"https://doi.org/10.1038/nature08952"},{"label":"Catling & Zahnle 2020, The Archean atmosphere (Sci. Adv.)","url":"https://doi.org/10.1126/sciadv.aax1420"},{"label":"Hoffman et al. 2017, Snowball Earth climate dynamics and Cryogenian geology-geobiology (Sci. Adv.)","url":"https://doi.org/10.1126/sciadv.1600983"},{"label":"Nance 2022, The supercontinent cycle and Earth's long-term climate (Ann. N.Y. Acad. Sci. 1515:33) — Huronian, Sturtian and Marinoan Snowball Earths: an ice-covered planet 'with a global mean temperature estimated at c. −50°C'","url":"https://doi.org/10.1111/nyas.14849"}],"group":"Climate","order":30,"inSnapshot":true,"tileLabel":"Avg. temperature","headline":2,"chipLabel":"Temperature","maxHonestGap":5000,"kids":{"order":1,"short":"Warmth","question":"How warm is Earth?","lo":8,"hi":27,"sub":"{v}°C","stops":[{"max":11,"word":"Freezing","emoji":"🥶"},{"max":14,"word":"Chilly","emoji":"🧊"},{"max":17,"word":"Just right","emoji":"😊"},{"max":21,"word":"Warm","emoji":"😎"},{"max":999,"word":"Hot!","emoji":"🥵"}]}},{"id":"co2","label":"Atmospheric CO₂","unit":"ppm","format":"integer","interpolation":"smooth","accent":"#a0d468","note":"Greenhouse gas. ~4500 ppm in the Cambrian; ~280 pre-industrial; climbing fast now.","anchors":[{"year":-4000000000,"value":100000},{"year":-2500000000,"value":30000},{"year":-1000000000,"value":8000},{"year":-540000000,"value":4500},{"year":-500000000,"value":4000},{"year":-445000000,"value":3800},{"year":-400000000,"value":2000},{"year":-340000000,"value":800},{"year":-300000000,"value":300},{"year":-252000000,"value":900},{"year":-200000000,"value":2000},{"year":-150000000,"value":1100},{"year":-100000000,"value":1000},{"year":-66000000,"value":600},{"year":-50000000,"value":850},{"year":-34000000,"value":500},{"year":-15000000,"value":400},{"year":-2600000,"value":300},{"year":-20000,"value":190},{"year":-10050,"value":253},{"year":-9800,"value":256},{"year":-9550,"value":266},{"year":-9050,"value":266},{"year":-8050,"value":264},{"year":-7050,"value":261},{"year":-6050,"value":260},{"year":-5050,"value":260},{"year":-4050,"value":265},{"year":-3050,"value":270},{"year":-2050,"value":273},{"year":-1050,"value":275},{"year":-50,"value":278},{"year":500,"value":278},{"year":750,"value":279},{"year":1000,"value":280},{"year":1250,"value":282},{"year":1500,"value":283},{"year":1650,"value":276},{"year":1750,"value":278},{"year":1800,"value":280},{"year":1900,"value":296},{"year":1901,"value":296},{"year":1902,"value":296},{"year":1903,"value":296},{"year":1904,"value":297},{"year":1905,"value":297},{"year":1906,"value":297},{"year":1907,"value":298},{"year":1908,"value":298},{"year":1909,"value":298},{"year":1910,"value":299},{"year":1960,"value":317},{"year":2000,"value":369},{"year":2024,"value":423}],"sources":[{"label":"Foster et al. 2017, Future climate forcing potentially without precedent in the last 420 million years (Nat. Commun.)","url":"https://doi.org/10.1038/ncomms14845"},{"label":"NOAA GML, Mauna Loa annual mean CO₂ (modern)","url":"https://gml.noaa.gov/webdata/ccgg/trends/co2/co2_annmean_mlo.txt"},{"label":"NOAA GML, global annual mean CO₂ (marine surface sites; 2024 = 422.79 ppm)","url":"https://gml.noaa.gov/webdata/ccgg/trends/co2/co2_annmean_gl.txt"},{"label":"Law Dome ice core, MacFarling Meure et al. 2006 (GRL)","url":"https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2006GL026152"},{"label":"Catling & Zahnle 2020, The Archean atmosphere (Sci. Adv.)","url":"https://doi.org/10.1126/sciadv.aax1420"},{"label":"Bereiter et al. 2015, Revision of the EPICA Dome C CO2 record from 800 to 600 kyr before present (GRL 42:542) — NOAA Antarctic ice-core CO2 composite (antarctica2015co2composite.txt); the Holocene/Common Era section of the composite is built from EPICA Dome C (Monnin et al.), Law Dome and WAIS Divide","url":"https://www.ncei.noaa.gov/pub/data/paleo/icecore/antarctica/antarctica2015co2composite.txt"}],"group":"Atmosphere","order":20,"inSnapshot":true,"tileLabel":"CO₂","headline":3,"chipLabel":"CO₂","maxHonestGap":5000},{"id":"methane","label":"Atmospheric CH₄","unit":"ppb","format":"integer","interpolation":"smooth","accent":"#e6b800","note":"Potent greenhouse gas. Archean values are estimates: xenon isotopes imply >0.5% (>5000 ppmv) about 3.5 billion years ago and Archean biogenic levels of ~10³ ppmv (Catling & Zahnle 2020); others argue Archean methane was relatively low, 1–50 ppmv (as reported by Kasting & Ji 2025). Later deep-time values are model estimates (Beerling et al. 2009: very high in the Permo-Carboniferous coal swamps, very low in the Triassic coal gap); ~700 ppb pre-industrial in ice cores; now near 1930 ppb and rising.","anchors":[{"year":-3500000000,"value":5000000},{"year":-2500000000,"value":1000000},{"year":-2300000000,"value":500},{"year":-1000000000,"value":800},{"year":-300000000,"value":12000},{"year":-250000000,"value":100},{"year":-150000000,"value":3000},{"year":-20000,"value":355},{"year":1750,"value":705},{"year":1900,"value":876},{"year":1960,"value":1220},{"year":2000,"value":1770},{"year":2024,"value":1930}],"sources":[{"label":"NOAA GML, global annual mean CH₄ (modern)","url":"https://gml.noaa.gov/webdata/ccgg/trends/ch4/ch4_annmean_gl.txt"},{"label":"Catling & Zahnle 2020, The Archean atmosphere (Sci. Adv.)","url":"https://doi.org/10.1126/sciadv.aax1420"},{"label":"Kasting & Ji 2025, Atmospheric oxygen and methane on the early Earth (Phil. Trans. R. Soc. B)","url":"https://doi.org/10.1098/rstb.2024.0093"},{"label":"Beerling, Berner, Mackenzie, Harfoot & Pyle 2009, Methane and the CH4-related greenhouse effect over the past 400 million years (Am. J. Sci. 309:97) — modelled ∼12,000 ppb in the Permo-Carboniferous, ∼100 ppb in the Triassic 'coal gap', 2000–4000 ppb Mesozoic average, <1000 ppb Cenozoic","url":"https://doi.org/10.2475/02.2009.01"},{"label":"Wikipedia — Permian–Triassic extinction event (coal gap: no coal deposits known from the Early Triassic)","url":"https://en.wikipedia.org/wiki/Permian%E2%80%93Triassic_extinction_event"},{"label":"Wikipedia — Early Triassic (251.902–247 Ma)","url":"https://en.wikipedia.org/wiki/Early_Triassic"},{"label":"Loulergue et al. 2008, Orbital and millennial-scale features of atmospheric CH4 over the past 800,000 years (Nature 453:383) — NOAA EPICA Dome C CH4 (edc-ch4-2008.txt): 355 ppbv at gas age 21,986 yr BP","url":"https://www.ncei.noaa.gov/pub/data/paleo/icecore/antarctica/epica_domec/edc-ch4-2008.txt"},{"label":"Law Dome ice core CH4 spline, NOAA04 scale (Etheridge et al. 1998; MacFarling Meure et al. 2006) — NOAA law2006.txt: 1750 = 705.3, 1900 = 875.6, 1960 = 1220.3 ppb","url":"https://www.ncei.noaa.gov/pub/data/paleo/icecore/antarctica/law/law2006.txt"}],"group":"Atmosphere","order":21,"tileLabel":"Methane"},{"id":"oxygen","label":"Atmospheric oxygen","unit":"%","format":"decimal2","interpolation":"smooth","accent":"#6cc5ff","note":"Peaked near 30% in the Carboniferous; flat for all of human history.","anchors":[{"year":-4600000000,"value":0.00002},{"year":-3500000000,"value":0.00002},{"year":-2450000000,"value":0.00002},{"year":-2300000000,"value":2},{"year":-1800000000,"value":2},{"year":-1400000000,"value":0.78},{"year":-800000000,"value":4},{"year":-600000000,"value":9},{"year":-440000000,"value":13},{"year":-393000000,"value":14.5},{"year":-323000000,"value":20},{"year":-300000000,"value":30},{"year":-252000000,"value":15},{"year":-242000000,"value":18.5},{"year":-66000000,"value":25},{"year":-800000,"value":21.1},{"year":1800,"value":20.95},{"year":2024,"value":20.95}],"sources":[{"label":"Krause et al. 2018, Stepwise oxygenation of the Paleozoic atmosphere (Nat. Commun.)","url":"https://doi.org/10.1038/s41467-018-06383-y"},{"label":"Beerling & Berner 2000, Impact of a Permo-Carboniferous high O2 event on the terrestrial carbon cycle (PNAS)","url":"https://doi.org/10.1073/pnas.220280097"},{"label":"Lyons, Reinhard & Planavsky 2014, The rise of oxygen in Earth's early ocean and atmosphere (Nature 506:307)","url":"https://doi.org/10.1038/nature13068"},{"label":"Kasting & Ji 2025, Atmospheric oxygen and methane on the early Earth (Phil. Trans. R. Soc. B)","url":"https://doi.org/10.1098/rstb.2024.0093"},{"label":"Pavlov & Kasting 2002, Mass-independent fractionation of sulfur isotopes in Archean sediments: strong evidence for an anoxic Archean atmosphere (Astrobiology 2:27) — O2 < 10⁻⁵ PAL before 2.3 Ga","url":"https://pubmed.ncbi.nlm.nih.gov/12449853/"},{"label":"Park et al. 2025, Breathing life into the boring billion (PNAS 122:e2513030122) — 1.4 Ga fluid inclusions: pO2 7.84 ± 3.05 mbar = 3.7 ± 1.5 % PAL (≈0.78 % of the air)","url":"https://www.pnas.org/doi/10.1073/pnas.2513030122"},{"label":"Catling & Zahnle 2020, The Archean atmosphere (Sci. Adv. 6:eaax1420) — surface O2 <10⁻⁶ times present (≈0.00002 % of the air)","url":"https://doi.org/10.1126/sciadv.aax1420"},{"label":"Wikipedia — Geological history of oxygen (O2 around 13 % in the early Silurian; falls from 30 % to below 15 % around 252 Ma)","url":"https://en.wikipedia.org/wiki/Geological_history_of_oxygen"},{"label":"Wikipedia — Middle Triassic (247–237 Ma)","url":"https://en.wikipedia.org/wiki/Middle_Triassic"},{"label":"Belcher et al. 2021, The rise of angiosperms strengthened fire feedbacks and improved the regulation of atmospheric oxygen (Nat. Commun. 12:503) — COPSE: O2 lowered from ~30 % to ~25 % by the end of the Cretaceous","url":"https://doi.org/10.1038/s41467-020-20772-2"},{"label":"Stolper et al. 2016, A Pleistocene ice core record of atmospheric O2 concentrations (Science 353:1427) — PO2 declined by 7 per mil (0.7 %) over the past 800,000 years (20.95 × 1.007 ≈ 21.1 %)","url":"https://doi.org/10.1126/science.aaf5445"}],"group":"Atmosphere","order":22,"tileLabel":"Oxygen","headline":7,"chipLabel":"Oxygen","maxHonestGap":50000000,"kids":{"order":3,"short":"Air","question":"How much air?","lo":12,"hi":32,"sub":"{v}% oxygen","stops":[{"max":15,"word":"Thin","emoji":"😦"},{"max":19,"word":"Okay","emoji":"🙂"},{"max":23,"word":"Fresh!","emoji":"😃"},{"max":999,"word":"Super rich","emoji":"🤩"}]}},{"id":"ice-cover","label":"Land Ice Cover","unit":"%","format":"decimal1","interpolation":"smooth","accent":"#7ec8e3","note":"Share of land under ice sheets & glaciers. Near-zero in the dinosaur hothouse; peaked at the last Ice Age.","anchors":[{"year":-2400000000,"value":5},{"year":-2300000000,"value":60},{"year":-2200000000,"value":5},{"year":-1600000000,"value":0},{"year":-1100000000,"value":0},{"year":-750000000,"value":5},{"year":-700000000,"value":85},{"year":-650000000,"value":30},{"year":-635000000,"value":80},{"year":-600000000,"value":8},{"year":-540000000,"value":4},{"year":-500000000,"value":3},{"year":-445000000,"value":22},{"year":-430000000,"value":5},{"year":-360000000,"value":4},{"year":-330000000,"value":20},{"year":-300000000,"value":25},{"year":-280000000,"value":12},{"year":-250000000,"value":1},{"year":-200000000,"value":0},{"year":-150000000,"value":0.5},{"year":-135000000,"value":2.4},{"year":-90000000,"value":0.2},{"year":-66000000,"value":0.5},{"year":-50000000,"value":0.3},{"year":-34000000,"value":6},{"year":-28000000,"value":8.9},{"year":-22000000,"value":8.9},{"year":-15000000,"value":8},{"year":-10500000,"value":10},{"year":-7000000,"value":10},{"year":-4700000,"value":10},{"year":-3200000,"value":10},{"year":-2600000,"value":10},{"year":-1738050,"value":12.8},{"year":-1158050,"value":13.2},{"year":-794050,"value":21.5},{"year":-772050,"value":10.8},{"year":-747050,"value":18.9},{"year":-694050,"value":11.2},{"year":-625050,"value":23.8},{"year":-570050,"value":10.8},{"year":-535050,"value":18.1},{"year":-490050,"value":11.3},{"year":-427050,"value":24.9},{"year":-402050,"value":7.7},{"year":-344050,"value":21.7},{"year":-321050,"value":10.1},{"year":-268050,"value":21.2},{"year":-204050,"value":10.7},{"year":-136050,"value":25},{"year":-119050,"value":10},{"year":-98050,"value":12},{"year":-81050,"value":12.9},{"year":-64050,"value":19.7},{"year":-44050,"value":18.4},{"year":-30050,"value":21.5},{"year":-20000,"value":25},{"year":-11700,"value":14},{"year":-6000,"value":10.5},{"year":1800,"value":10.5},{"year":1950,"value":10.3},{"year":2024,"value":10}],"sources":[{"label":"Wikipedia — Late Paleozoic icehouse","url":"https://en.wikipedia.org/wiki/Late_Paleozoic_icehouse"},{"label":"Wikipedia — Cryosphere","url":"https://en.wikipedia.org/wiki/Cryosphere"},{"label":"Hoffman et al. 2017, Snowball Earth climate dynamics and Cryogenian geology-geobiology (Sci. Adv. 3:e1600983) — 'virtually no ice sheets' in the 1.5-Gyr Proterozoic glacial gap before the Cryogenian","url":"https://doi.org/10.1126/sciadv.1600983"},{"label":"Olsen et al. 2022, Arctic ice and the ecological rise of the dinosaurs (Sci. Adv. 8:eabo6342) — no evidence of polar ice sheets in the Late Triassic–earliest Jurassic","url":"https://www.science.org/doi/10.1126/sciadv.abo6342"},{"label":"Wang et al. 2023, Ice sheet expansion in the Cretaceous greenhouse world (Fundamental Research) — Valanginian (~135 Ma) ice 0–53 % of present Antarctica; 26 % × Antarctica's ~8.9 % share of land = 2.4 %","url":"https://pmc.ncbi.nlm.nih.gov/articles/PMC11670679/"},{"label":"O'Brien et al. 2020, The enigma of Oligocene climate and global surface temperature evolution (PNAS 117:25302) — Antarctic ice sheets near modern size through the Oligocene (no Greenland ice sheet → Antarctica's share, 8.9 %)","url":"https://doi.org/10.1073/pnas.2003914117"},{"label":"Miller et al. 2020, Cenozoic sea-level and cryospheric evolution (Sci. Adv. 6:eaaz1346) — smoothed sea level (NOAA miller2020rsl-sm): −0.4 to −6.5 m at 10.5–3.2 Ma (ice ≈ modern, held at 10 %); −26.6 m at 1.16 Ma and −23.2 m at 1.74 Ma, converted as below","url":"https://www.ncei.noaa.gov/pub/data/paleo/contributions_by_author/miller2020/miller2020rsl-sm-noaa.txt"},{"label":"Spratt & Lisiecki 2016, A Late Pleistocene sea level stack (Clim. Past 12) — long PC1 at each glacial low / interglacial high, 32–796 ka; ice % = 10 − 0.12 × sea level (m), which maps today (0 m) to 10 % and the USGS LGM pairing (sea level about 125 m lower, 25 % of land under ice) to 25 %","url":"https://www.ncei.noaa.gov/pub/data/paleo/contributions_by_author/spratt2016/spratt2016.txt"},{"label":"Wikipedia — Last Glacial Maximum (USGS: permanent summer ice covered around 8 % of Earth's surface and 25 % of the land area at the LGM; sea level about 125 m lower)","url":"https://en.wikipedia.org/wiki/Last_Glacial_Maximum"}],"group":"Climate","order":31,"inSnapshot":true,"tileLabel":"Land ice cover","headline":6,"chipLabel":"Ice cover","maxHonestGap":10000,"kids":{"order":4,"short":"Ice","question":"How much ice?","lo":0,"hi":30,"sub":"{v}% of land","stops":[{"max":3,"word":"Almost none","emoji":"🏝️"},{"max":8,"word":"A little","emoji":"💧"},{"max":15,"word":"Some ice","emoji":"❄️"},{"max":999,"word":"Frozen!","emoji":"🧊"}]}},{"id":"sea-level","label":"Sea level","unit":"m","format":"signed2","interpolation":"smooth","accent":"#4fb0e0","note":"Relative to today. High in warm ice-free ages; low during glaciations.","anchors":[{"year":-540000000,"value":60},{"year":-340000000,"value":-30},{"year":-300000000,"value":-20},{"year":-252000000,"value":20},{"year":-200000000,"value":60},{"year":-90000000,"value":100},{"year":-66000000,"value":120},{"year":-34000000,"value":40},{"year":-15000000,"value":20},{"year":-2600000,"value":5},{"year":-20000,"value":-120},{"year":1800,"value":-0.02},{"year":1900,"value":0},{"year":1950,"value":0.05},{"year":1990,"value":0.13},{"year":2010,"value":0.19},{"year":2024,"value":0.23}],"sources":[{"label":"Haq & Schutter 2008, A Chronology of Paleozoic Sea-Level Changes (Science)","url":"https://doi.org/10.1126/science.1161648"},{"label":"Miller et al. 2005, The Phanerozoic Record of Global Sea-Level Change (Science)","url":"https://doi.org/10.1126/science.1116412"},{"label":"Wikipedia — Sea level rise","url":"https://en.wikipedia.org/wiki/Sea_level_rise"},{"label":"Kominz et al. 2008, Late Cretaceous to Miocene sea-level estimates from the New Jersey and Delaware coastal plain coreholes (Basin Research 20:211) — abstract in the NOAA Miller et al. 2005 dataset: long-term sea level 'about 75–110 m in the Late Cretaceous'","url":"https://www.ncei.noaa.gov/pub/data/paleo/contributions_by_author/miller2005/miller2005-backstrip-noaa.txt"}],"group":"Climate","order":32,"inSnapshot":true,"headline":5,"chipLabel":"Sea level","maxHonestGap":2000,"drivesShoreline":true},{"id":"ocean-ph","label":"Ocean Surface pH","unit":"","format":"decimal2","interpolation":"smooth","accent":"#c07cd6","note":"Acidity of surface seawater (lower = more acidic). Between 1950 and 2020 the average surface pH fell from about 8.15 to 8.05 as the ocean took up CO₂. Values before 1950 are not shown because no reconstruction was read; past drops (e.g. ~0.3 units at the PETM) are told by moments and connections.","anchors":[{"year":1950,"value":8.15},{"year":2020,"value":8.05}],"sources":[{"label":"Wikipedia — Ocean acidification","url":"https://en.wikipedia.org/wiki/Ocean_acidification"}],"group":"Climate","order":33,"tileLabel":"Ocean pH","naBefore":1950},{"id":"vegetation","label":"Forest Cover","unit":"%","format":"integer","interpolation":"smooth","accent":"#5cb85c","note":"Share of the world's habitable land (14.9 billion ha of land, 71% habitable, per Our World in Data) covered by forest. 8000 BCE: 57% (6 billion ha). 3000 BCE: 10% of the total loss gone (5.8 billion ha). 1700: still more than half. 1900: half the total loss gone (5 billion ha). 2020: 4 billion ha left — one-third lost. Percentages after 8000 BCE are those hectares divided by habitable land. Not shown before 8000 BCE: no read source gives a global figure earlier.","anchors":[{"year":-8000,"value":57},{"year":-3000,"value":55},{"year":1700,"value":50},{"year":1900,"value":47},{"year":2020,"value":38}],"sources":[{"label":"Ritchie 2021, The world has lost one-third of its forests, but an end to deforestation is possible (Our World in Data) — 57% of habitable land forested 10,000 years ago (6 billion ha); 10% of the loss by 5,000 years ago; more than half still forested in 1700; half the loss by 1900; 4 billion ha today; 14.9 billion ha of land, 71% habitable","url":"https://ourworldindata.org/world-lost-one-third-forests"},{"label":"Our World in Data — Deforestation and forest loss (19 million ha cleared per decade 1700–1850, Williams 2006)","url":"https://ourworldindata.org/deforestation"},{"label":"Wikipedia — Deforestation (about 31% of Earth's land is forest; one-third less than before agriculture, half of that loss in the last century)","url":"https://en.wikipedia.org/wiki/Deforestation"}],"group":"Life","order":40,"inSnapshot":true,"tileLabel":"Forest cover","naBefore":-8000},{"id":"biodiversity","label":"Marine biodiversity","unit":"genera","format":"integer","interpolation":"linear","accent":"#7fd8c8","note":"Known marine animal genera. The Great Dying and the dinosaur extinction show as sharp drops.","anchors":[{"year":-4000000000,"value":0},{"year":-3000000000,"value":0},{"year":-2000000000,"value":0},{"year":-1350000000,"value":0},{"year":-900000000,"value":0},{"year":-600000000,"value":5},{"year":-560000000,"value":30},{"year":-540000000,"value":300},{"year":-500000000,"value":900},{"year":-450000000,"value":1700},{"year":-445000000,"value":1150},{"year":-400000000,"value":1450},{"year":-359000000,"value":1200},{"year":-320000000,"value":1600},{"year":-300000000,"value":1900},{"year":-260000000,"value":1950},{"year":-253000000,"value":1850},{"year":-252000000,"value":520},{"year":-250000000,"value":540},{"year":-230000000,"value":850},{"year":-201000000,"value":1050},{"year":-199000000,"value":980},{"year":-150000000,"value":1700},{"year":-100000000,"value":2600},{"year":-67000000,"value":2850},{"year":-65000000,"value":2450},{"year":-50000000,"value":3400},{"year":-34500000,"value":3810},{"year":-33000000,"value":3590},{"year":-23000000,"value":4320},{"year":-15000000,"value":4400},{"year":2024,"value":5000}],"sources":[{"label":"Rohde & Muller 2005, Cycles in fossil diversity (Nature)","url":"https://doi.org/10.1038/nature03339"},{"label":"Sepkoski's Online Genus Database (S. Peters, UW-Madison) — the 34.5, 33 and 23 Ma values count every genus ranging through that time, scaled onto this curve between the 50 and 15 Ma anchors","url":"https://strata.geology.wisc.edu/jack/"}],"group":"Life","order":41,"inSnapshot":true,"tileLabel":"Marine life","maxHonestGap":15100000,"kids":{"order":2,"short":"Life","question":"How much life?","lo":0,"hi":5000,"sub":"in the sea","stops":[{"max":800,"word":"Just starting","emoji":"🌱"},{"max":2000,"word":"Growing","emoji":"🐟"},{"max":3500,"word":"Lots of life","emoji":"🐠"},{"max":1000000000,"word":"Teeming!","emoji":"🐋"}]}},{"id":"life-expectancy","label":"Life expectancy","unit":"yrs","format":"decimal1","interpolation":"linear","accent":"#c79bf2","naBefore":-12000,"note":"At birth, global average. Early figures are skewed low by infant mortality; the Roman-era value is a model life table for the Roman population, not a world figure.","anchors":[{"year":-12000,"value":24},{"year":-10000,"value":24.6},{"year":-7000,"value":25.5},{"year":1,"value":25},{"year":200,"value":25},{"year":1800,"value":28.5},{"year":1820,"value":29},{"year":1850,"value":29.3},{"year":1870,"value":29.7},{"year":1900,"value":32},{"year":1913,"value":34.1},{"year":1950,"value":46.4},{"year":1973,"value":57.7},{"year":2000,"value":66.4},{"year":2019,"value":72.6},{"year":2021,"value":70.9},{"year":2023,"value":73.2}],"sources":[{"label":"Our World in Data (life expectancy)","url":"https://ourworldindata.org/life-expectancy"},{"label":"Eshed, V., Gopher, A., Gage, T. B. & Hershkovitz, I. (2004), 'Has the transition to agriculture reshaped the demographic structure of prehistoric populations? New evidence from the Levant', American Journal of Physical Anthropology 124(4), 315-329 - life expectancy at birth of 24.6 years for the Natufian (217 skeletons, 7 sites) and 25.5 years for the Neolithic (262 skeletons, 14 sites)","url":"https://onlinelibrary.wiley.com/doi/10.1002/ajpa.10332"},{"label":"Gurven, M. & Kaplan, H. (2007), 'Longevity Among Hunter-Gatherers: A Cross-Cultural Examination', Population and Development Review 33(2), 321-365 - ethnographic hunter-gatherer life expectancy at birth of 21-37 years, averaging about 30, with modal adult age at death of 68-78 for those surviving childhood","url":"https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1728-4457.2007.00171.x"},{"label":"Riley, J. C. (2005), 'Estimates of Regional and Global Life Expectancy, 1800-2001', Population and Development Review 31(3), 537-543 - the source of the existing 1800 anchor; Riley's reconstruction BEGINS at 1800 and does not extend earlier","url":"https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1728-4457.2005.00083.x"},{"label":"University of Texas, Department of Classics — Roman Life Expectancy (life table approximating the Roman population, e(0) = 25, after Coale-Demeny Model South Level 3 via Parkin; notes several scholars think 25 too optimistic)","url":"https://web.archive.org/web/20120427061404/http://www.utexas.edu/depts/classics/documents/Life.html"},{"label":"Our World in Data — Life expectancy at birth, World (grapher data)","url":"https://ourworldindata.org/grapher/life-expectancy"}],"group":"Humanity","order":11,"inSnapshot":true,"headline":4,"chipLabel":"Life expectancy","maxHonestGap":250},{"id":"day-length","label":"Length of day","unit":"h","format":"decimal1","interpolation":"linear","accent":"#c0b0e8","note":"Earth spins slower over time as tides brake it and the Moon drifts away - deep-time days were shorter. The day seems to have stalled near 19 hours from about 2 to 1 billion years ago.","anchors":[{"year":-4500000000,"value":5},{"year":-2650000000,"value":17.3},{"year":-2460000000,"value":16.9},{"year":-2000000000,"value":19},{"year":-1000000000,"value":19},{"year":-620000000,"value":21.9},{"year":-70000000,"value":23.5},{"year":2024,"value":24}],"sources":[{"label":"Wikipedia — Tidal acceleration","url":"https://en.wikipedia.org/wiki/Tidal_acceleration"},{"label":"Wikipedia — Earth's rotation","url":"https://en.wikipedia.org/wiki/Earth's_rotation"},{"label":"Mitchell, R. N. & Kirscher, U. (2023), Mid-Proterozoic day length stalled by tidal resonance (Nature Geoscience 16, 567-569; Extended Data Table 1)","url":"https://www.nature.com/articles/s41561-023-01202-6"}],"group":"Planet","order":50},{"id":"solar-luminosity","label":"Solar luminosity","unit":"%","format":"decimal1","interpolation":"linear","accent":"#ffcc33","note":"The Sun steadily brightens (~7% per billion years). It was ~95.5% as bright at 540 Mya - the \"faint young Sun\".","anchors":[{"year":-4600000000,"value":70},{"year":-3500000000,"value":77},{"year":-2500000000,"value":83},{"year":-1000000000,"value":92},{"year":-540000000,"value":95.5},{"year":-500000000,"value":95.8},{"year":-450000000,"value":96.2},{"year":-400000000,"value":96.6},{"year":-350000000,"value":97},{"year":-300000000,"value":97.4},{"year":-252000000,"value":97.8},{"year":-200000000,"value":98.3},{"year":-150000000,"value":98.7},{"year":-100000000,"value":99.1},{"year":-66000000,"value":99.4},{"year":-34000000,"value":99.7},{"year":-15000000,"value":99.9},{"year":-2600000,"value":100},{"year":2024,"value":100}],"sources":[{"label":"Gough 1981, Solar interior structure and luminosity variations (Solar Physics)","url":"https://link.springer.com/article/10.1007/BF00151270"},{"label":"Bahcall, Pinsonneault & Basu 2001, Solar Models: current epoch and time dependences, neutrinos, and helioseismological properties (Astrophys. J.)","url":"https://arxiv.org/abs/astro-ph/0010346"}],"group":"Planet","order":51}]