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Broadly stable atmospheric CO2 and CH4 levels over the past 3 million years

  • Lüthi, D. et al. High-resolution carbon dioxide concentration record 650,000–800,000 years before present. Nature 453, 379–382 (2008).

    Article 
    ADS 
    PubMed 

    Google Scholar
     

  • Bereiter, B. et al. Revision of the EPICA Dome C CO2 record from 800 to 600 kyr before present. Geophys. Res. Lett. 42, 542–549 (2015).

    Article 
    ADS 

    Google Scholar
     

  • Loulergue, L. et al. Orbital and millennial-scale features of atmospheric CH4 over the past 800,000 years. Nature 453, 383–386 (2008).

    Article 
    ADS 
    CAS 
    PubMed 

    Google Scholar
     

  • Whillans, I. M. & Cassidy, W. A. Catch a falling star: meteorites and old ice. Science 222, 55–57 (1983).

    Article 
    ADS 
    CAS 
    PubMed 

    Google Scholar
     

  • Higgins, J. A. et al. Atmospheric composition 1 million years ago from blue ice in the Allan Hills, Antarctica. Proc. Natl Acad. Sci. USA 112, 6887–6891 (2015).

    Article 
    ADS 
    CAS 
    PubMed 
    PubMed Central 

    Google Scholar
     

  • Yan, Y. et al. Two-million-year-old snapshots of atmospheric gases from Antarctic ice. Nature 574, 663–666 (2019).

    Article 
    ADS 
    CAS 
    PubMed 

    Google Scholar
     

  • Shackleton, S. et al. Miocene and Pliocene ice and air from the Allan Hills blue ice area, East Antarctica. Proc. Natl Acad. Sci. USA 122, e2502681122 (2025).

    Article 
    CAS 
    PubMed 
    PubMed Central 

    Google Scholar
     

  • Clark, P. U., Shakun, J. D., Rosenthal, Y., Köhler, P. & Bartlein, P. J. Global and regional temperature change over the past 4.5 million years. Science 383, 884–890 (2024).

    Article 
    ADS 
    CAS 
    PubMed 

    Google Scholar
     

  • Clark, P. U. et al. Global mean sea level over the past 4.5 million years. Science 390, eadv8389 (2025).

    Article 
    CAS 
    PubMed 

    Google Scholar
     

  • Shackleton, N. J. et al. Oxygen isotope calibration of the onset of ice-rafting and history of glaciation in the North Atlantic region. Nature 307, 620–623 (1984).

    Article 
    ADS 
    CAS 

    Google Scholar
     

  • Clark, P. U. et al. The middle Pleistocene transition: characteristics, mechanisms, and implications for long-term changes in atmospheric pCO2. Quat. Sci. Rev. 25, 3150–3184 (2006).

    Article 
    ADS 

    Google Scholar
     

  • DeConto, R. M. et al. Thresholds for Cenozoic bipolar glaciation. Nature 455, 652–656 (2008).

    Article 
    ADS 
    CAS 
    PubMed 

    Google Scholar
     

  • Vizcaíno, M., Rupper, S. & Chiang, J. C. H. Permanent El Niño and the onset of Northern Hemisphere glaciations: mechanism and comparison with other hypotheses. Paleoceanography 25, PA2205 (2010).

    Article 
    ADS 

    Google Scholar
     

  • Berends, C. J., Köhler, P., Lourens, L. J. & van de Wal, R. S. W. On the cause of the mid-Pleistocene transition. Rev. Geophys. 59, e2020RG000727 (2021).

    Article 
    ADS 

    Google Scholar
     

  • Ridgwell, A. & Zeebe, R. The role of the global carbonate cycle in the regulation and evolution of the Earth system. Earth Planet. Sci. Lett. 234, 299–315 (2005).

    Article 
    ADS 
    CAS 

    Google Scholar
     

  • Zeebe, R. E. & Caldeira, K. Close mass balance of long-term carbon fluxes from ice-core CO2 and ocean chemistry records. Nat. Geosci. 1, 312–315 (2008).

    Article 
    ADS 
    CAS 

    Google Scholar
     

  • Hopcroft, P. O. et al. Polar amplification of Pliocene climate by elevated trace gas radiative forcing. Proc. Natl. Acad. Sci. USA 117, 23401–23407 (2020).

    Article 
    ADS 
    CAS 
    PubMed 
    PubMed Central 

    Google Scholar
     

  • Rae, J. W. B. et al. Atmospheric CO2 over the past 66 million years from marine archives. Annu. Rev. Earth Planet. Sci. 49, 609–641 (2021).

    Article 
    ADS 
    CAS 

    Google Scholar
     

  • The Cenozoic CO2 Proxy Integration Project (CenCO2PIP) Consortium Toward a Cenozoic history of atmospheric CO2. Science 382, eadi5177 (2023)

  • Bender, M. L., Barnett, B., Dreyfus, G., Jouzel, J. & Porcelli, D. The contemporary degassing rate of 40Ar from the solid Earth. Proc. Natl Acad. Sci. USA 105, 8232–8237 (2008).

    Article 
    ADS 
    CAS 
    PubMed 
    PubMed Central 

    Google Scholar
     

  • Yan, Y. et al. Enhanced moisture delivery into Victoria Land, East Antarctica, during the early Last Interglacial: implications for West Antarctic Ice Sheet stability. Clim. Past 17, 1841–1855 (2021).

    Article 

    Google Scholar
     

  • Spaulding, N. E. et al. Climate archives from 90 to 250 ka in horizontal and vertical ice cores from the Allan Hills Blue Ice Area. Antarctica. Quat. Res. 80, 562–574 (2013).

    Article 
    CAS 

    Google Scholar
     

  • Bereiter, B., Schwander, J., Lüthi, D. & Stocker, T. F. Change in CO2 concentration and O2/N2 ratio in ice cores due to molecular diffusion. Geophys. Res. Lett. 36, L05703 (2009).

    Article 
    ADS 

    Google Scholar
     

  • Ikeda, T. et al. Extreme fractionation of gases caused by formation of clathrate hydrates in Vostok Antarctic Ice. Geophys. Res. Lett. 26, 91–94 (1999).

    Article 
    ADS 
    CAS 

    Google Scholar
     

  • Extier, T. et al. On the use of δ18Oatm for ice core dating. Quat. Sci. Rev. 185, 244–257 (2018).

    Article 
    ADS 

    Google Scholar
     

  • Bouchet, M. et al. The Antarctic Ice Core Chronology 2023 (AICC2023) chronological framework and associated timescale for the European Project for Ice Coring in Antarctica (EPICA) Dome C ice core. Clim. Past 19, 2257–2286 (2023).

    Article 

    Google Scholar
     

  • Landais, A. et al. What drives the millennial and orbital variations of δ18Oatm? Quat. Sci. Rev. 29, 235–246 (2010).

    Article 
    ADS 

    Google Scholar
     

  • Berner, W., Stauffer, B. & Oeschger, H. Past atmospheric composition and climate, gas parameters measured on ice cores. Nature 276, 53–55 (1978).

    Article 
    ADS 
    CAS 

    Google Scholar
     

  • Neftel, A., Oeschger, H., Schwander, J. & Stauffer, B. Carbon dioxide concentration in bubbles of natural cold ice. J. Phys. Chem. 87, 4116–4120 (1983).

    Article 
    ADS 
    CAS 

    Google Scholar
     

  • Anklin, M., Barnola, J.-M., Schwander, J., Stauffer, B. & Raynaud, D. Processes affecting the CO2 concentrations measured in Greenland ice. Tellus B 47, 461–470 (1995).

    Article 
    ADS 

    Google Scholar
     

  • Souchez, R., Janssens, L., Lemmens, M. & Stauffer, B. Very low oxygen concentration in basal ice from Summit, central Greenland. Geophys. Res. Lett. 22, 2001–2004 (1995).

    Article 
    ADS 
    CAS 

    Google Scholar
     

  • Smith, H. J., Wahlen, M., Mastroianni, D., Taylor, K. & Mayewski, P. The CO2 concentration of air trapped in Greenland Ice Sheet Project 2 ice formed during periods of rapid climate change. J. Geophys. Res. Oceans 102, 26577–26582 (1997).

    Article 
    ADS 
    CAS 

    Google Scholar
     

  • Eggleston, S., Schmitt, J., Bereiter, B., Schneider, R. & Fischer, H. Evolution of the stable carbon isotope composition of atmospheric CO2 over the last glacial cycle. Paleoceanography 31, 434–452 (2016).

    Article 
    ADS 

    Google Scholar
     

  • Bauska, T. K., Marcott, S. A. & Brook, E. J. Abrupt changes in the global carbon cycle during the last glacial period. Nat. Geosci. 14, 91–96 (2021).

    Article 
    ADS 
    CAS 

    Google Scholar
     

  • Chalk, T. B. et al. Causes of ice age intensification across the Mid-Pleistocene Transition. Proc. Natl Acad. Sci. USA 114, 13114–13119 (2017).

    Article 
    ADS 
    CAS 
    PubMed 
    PubMed Central 

    Google Scholar
     

  • Hönisch, B., Hemming, N. G., Archer, D., Siddall, M. & McManus, J. F. Atmospheric carbon dioxide concentration across the mid-Pleistocene transition. Science 324, 1551–1554 (2009).

    Article 
    ADS 
    PubMed 

    Google Scholar
     

  • Shackleton, S. et al. Global ocean heat content over the past 3 million years. Nature https://doi.org/10.1038/s41586-026-10116-3 (2026).

  • Snyder, C. W. Evolution of global temperature over the past two million years. Nature 538, 226–228 (2016).

    Article 
    ADS 
    CAS 
    PubMed 

    Google Scholar
     

  • Brierley, C. M. & Fedorov, A. V. Relative importance of meridional and zonal sea surface temperature gradients for the onset of the ice ages and Pliocene-Pleistocene climate evolution. Paleoceanography 25, PA2214 (2010).

    Article 
    ADS 

    Google Scholar
     

  • Martínez-Garcia, A., Rosell-Melé, A., McClymont, E. L., Gersonde, R. & Haug, G. H. Subpolar link to the emergence of the modern Equatorial Pacific Cold Tongue. Science 328, 1550–1553 (2010).

    Article 
    ADS 
    PubMed 

    Google Scholar
     

  • Howell, F. W., Haywood, A. M., Dowsett, H. J. & Pickering, S. J. Sensitivity of Pliocene Arctic climate to orbital forcing, atmospheric CO2 and sea ice albedo parameterisation. Earth Planet. Sci. Lett. 441, 133–142 (2016).

    Article 
    ADS 
    CAS 

    Google Scholar
     

  • Feng, R. et al. Amplified Late Pliocene terrestrial warmth in northern high latitudes from greater radiative forcing and closed Arctic Ocean gateways. Earth Planet. Sci. Lett. 466, 129–138 (2017).

    Article 
    ADS 
    CAS 

    Google Scholar
     

  • Burton, L. E. et al. On the climatic influence of CO2 forcing in the Pliocene. Clim. Past 19, 747–764 (2023).

    Article 

    Google Scholar
     

  • Siever, R. Sedimentological consequences of a steady-state ocean-atmosphere. Sedimentology 11, 5–29 (1968).

    Article 
    ADS 
    CAS 

    Google Scholar
     

  • Walker, J. C. G. Carbon dioxide on the early earth. Origins Life Evol. Biosphere 16, 117–127 (1985).

    Article 
    ADS 
    CAS 

    Google Scholar
     

  • Coogan, L. A. & Dosso, S. E. Controls on the evolution of Cenozoic seawater chemistry. Geochim. Cosmochim. Acta 329, 22–37 (2022).

    Article 
    ADS 
    CAS 

    Google Scholar
     

  • Isson, T. T. et al. Evolution of the global carbon cycle and climate regulation on Earth. Global Biogeochem. Cycles 34, e2018GB006061 (2020).

    Article 
    ADS 
    CAS 

    Google Scholar
     

  • Takahashi, T., Olafsson, J., Goddard, J. G., Chipman, D. W. & Sutherland, S. C. Seasonal variation of CO2 and nutrients in the high-latitude surface oceans: a comparative study. Global Biogeochem. Cycles 7, 843–878 (1993).

    Article 
    ADS 
    CAS 

    Google Scholar
     

  • Lisiecki, L. E. & Raymo, M. E. A Pliocene-Pleistocene stack of 57 globally distributed benthic δ18O records. Paleoceanography 20, PA1003 (2005).

    ADS 

    Google Scholar
     

  • Steig, E. J. et al. Calibrated high-precision 17O-excess measurements using cavity ring-down spectroscopy with laser-current-tuned cavity resonance. Atmos. Meas. Tech. 7, 2421–2435 (2014).

    Article 
    CAS 

    Google Scholar
     

  • Ahn, J., Brook, E. J. & Howell, K. A high-precision method for measurement of paleoatmospheric CO2 in small polar ice samples. J. Glaciol. 55, 499–506 (2009).

    Article 
    ADS 
    CAS 

    Google Scholar
     

  • Grachev, A. M., Brook, E. J., Severinghaus, J. P. & Pisias, N. G. Relative timing and variability of atmospheric methane and GISP2 oxygen isotopes between 68 and 86 ka. Glob. Biogeochem. Cycles 23, GB3003 (2009).

    Article 

    Google Scholar
     

  • Lee, J. E. et al. An 83,000-year-old ice core from Roosevelt Island, Ross Sea, Antarctica. Clim. Past 16, 1691–1713 (2020).

    Article 
    ADS 

    Google Scholar
     

  • Epifanio, J. A. et al. Millennial and orbital-scale variability in a 54,000-year record of total air content from the South Pole ice core. Cryosphere 17, 4837–4851 (2023).

    Article 
    ADS 

    Google Scholar
     

  • Bauska, T. K., Brook, E. J., Mix, A. C. & Ross, A. High-precision dual-inlet IRMS measurements of the stable isotopes of CO2 and the N2O/CO2 ratio from polar ice core samples. Atmos. Meas. Tech. 7, 3825–3837 (2014).

    Article 
    CAS 

    Google Scholar
     

  • Assonov, S. S. & Brenninkmeijer, C. A. M. On the N2O correction used for mass spectrometric analysis of atmospheric CO2. Rapid Commun. Mass Spectrom. 20, 1809–1819 (2006).

    Article 
    ADS 
    CAS 
    PubMed 

    Google Scholar
     

  • Schneider, R., Schmitt, J., Köhler, P., Joos, F. & Fischer, H. A reconstruction of atmospheric carbon dioxide and its stable carbon isotopic composition from the penultimate glacial maximum to the last glacial inception. Clim. Past 9, 2507–2523 (2013).

    Article 

    Google Scholar
     

  • Bauska, T. K. et al. Carbon isotopes characterize rapid changes in atmospheric carbon dioxide during the last deglaciation. Proc. Natl Acad. Sci. USA 113, 3465–3470 (2016).

    Article 
    ADS 
    CAS 
    PubMed 
    PubMed Central 

    Google Scholar
     

  • Menking, J. A. et al. Multiple carbon cycle mechanisms associated with the glaciation of Marine Isotope Stage 4. Nat. Commun. 13, 5443 (2022).

    Article 
    ADS 
    CAS 
    PubMed 
    PubMed Central 

    Google Scholar
     

  • Tipple, B. J., Meyers, S. R. & Pagani, M. Carbon isotope ratio of Cenozoic CO2: a comparative evaluation of available geochemical proxies. Paleoceanography 25, PA3202 (2010).

    Article 
    ADS 

    Google Scholar
     

  • Sowers, T., Bender, M. & Raynaud, D. Elemental and isotopic composition of occluded O2 and N2 in polar ice. J. Geophys. Res. Atmos. 94, 5137–5150 (1989).

    Article 
    ADS 
    CAS 

    Google Scholar
     

  • Baggenstos, D. et al. Atmospheric gas records from Taylor Glacier, Antarctica, reveal ancient ice with ages spanning the entire last glacial cycle. Clim. Past 13, 943–958 (2017).

    Article 

    Google Scholar
     

  • Stolper, D. A., Bender, M. L., Dreyfus, G. B., Yan, Y. & Higgins, J. A. A Pleistocene ice core record of atmospheric O2 concentrations. Science 353, 1427–1430 (2016).

    Article 
    ADS 
    CAS 
    PubMed 

    Google Scholar
     

  • Yan, Y., Brook, E., Kurbatov, A., Severinghaus, J. & Higgins, J. Ice core evidence for atmospheric oxygen decline since the Mid-Pleistocene transition. Sci. Adv. 7, eabj9341 (2021).

    Article 
    ADS 
    CAS 
    PubMed 
    PubMed Central 

    Google Scholar
     

  • Durand, G. et al. Change in ice rheology during climate variations – implications for ice flow modelling and dating of the EPICA Dome C core. Clim. Past 3, 155–167 (2007).

    Article 

    Google Scholar
     

  • Krauss, F. Optimisation of a Continuous Sublimation Extraction Technique to Reconstruct Past CO2, CH4, and N2O Concentrations and δ13C-CO2 from Ice Cores. PhD thesis, Univ. Bern (2024).

  • Zhang, J., Quay, P. D. & Wilbur, D. O. Carbon isotope fractionation during gas-water exchange and dissolution of CO2. Geochim. Cosmochim. Acta 59, 107–114 (1995).

    Article 
    ADS 
    CAS 

    Google Scholar
     

  • Montross, S. et al. Debris-rich basal ice as a microbial habitat, Taylor Glacier, Antarctica. Geomicrobiol. J. 31, 76–81 (2014).

    Article 

    Google Scholar
     

  • Orsi, A. J. et al. Differentiating bubble-free layers from melt layers in ice cores using noble gases. J. Glaciol. 61, 585–594 (2015).

    Article 
    ADS 

    Google Scholar
     

  • Faure, G., Hoefs, J., Jones, L. M., Curtis, J. B. & Pride, D. E. Extreme 18O depletion in calcite and chert clasts from the Elephant Moraine on the East Antarctic ice sheet. Nature 332, 352–354 (1988).

    Article 
    ADS 
    CAS 

    Google Scholar
     

  • Barker, J. D., Grottoli, A. G. & Lyons, W. B. Stable isotope evidence for the biogeochemical transformation of ancient organic matter beneath Suess Glacier, Antarctica. Arctic Antarctic Alpine Res. 50, e1448643 (2018).

    Article 
    ADS 

    Google Scholar
     

  • Zhang, Y. G. et al. Refining the alkenone-pCO2 method I: lessons from the Quaternary glacial cycles. Geochim. Cosmochim. Acta 260, 177–191 (2019).

    Article 
    ADS 
    CAS 

    Google Scholar
     

  • Pagani, M., Liu, Z., LaRiviere, J. & Ravelo, A. C. High Earth-system climate sensitivity determined from Pliocene carbon dioxide concentrations. Nat. Geosci. 3, 27–30 (2010).

    Article 
    ADS 
    CAS 

    Google Scholar
     

  • Stoll, H. M. et al. Upregulation of phytoplankton carbon concentrating mechanisms during low CO2 glacial periods and implications for the phytoplankton pCO2 proxy. Quat. Sci. Rev. 208, 1–20 (2019).

    Article 
    ADS 

    Google Scholar
     

  • Badger, M. P. S. et al. Insensitivity of alkenone carbon isotopes to atmospheric CO2 at low to moderate CO2 levels. Clim. Past 15, 539–554 (2019).

    Article 

    Google Scholar
     

  • González-Lanchas, A. et al. Carbon isotopic fractionation of alkenones and gephyrocapsa coccoliths over the Late Quaternary (marine isotope stages 12–9) glacial-interglacial cycles at the Western Tropical Atlantic. Paleoceanogr. Paleoclimatol. 36, e2020PA004175 (2021).

    Article 

    Google Scholar
     

  • Seki, O. et al. Alkenone and boron-based Pliocene pCO2 records. Earth Planet. Sci. Lett. 292, 201–211 (2010).

    Article 
    ADS 
    CAS 

    Google Scholar
     

  • Da, J., Zhang, Y. G., Li, G., Meng, X. & Ji, J. Low CO2 levels of the entire Pleistocene epoch. Nat. Commun. 10, 4342 (2019).

    Article 
    ADS 
    PubMed 
    PubMed Central 

    Google Scholar
     

  • Foster, G. L. Seawater pH, pCO2 and [CO2–3] variations in the Caribbean Sea over the last 130 kyr: a boron isotope and B/Ca study of planktic foraminifera. Earth Planet. Sci. Lett. 271, 254–266 (2008).

    Article 
    ADS 
    CAS 

    Google Scholar
     

  • Martínez-Botí, M. A. et al. Plio-Pleistocene climate sensitivity evaluated using high-resolution CO2 records. Nature 518, 49–54 (2015).

    Article 
    ADS 
    PubMed 

    Google Scholar
     

  • Dyez, K. A., Hönisch, B. & Schmidt, G. A. Early Pleistocene obliquity-scale pCO– variability at ~1.5 million years ago. Paleoceanogr. Paleoclimatol. 33, 1270–1291 (2018).

    Article 
    ADS 
    PubMed 
    PubMed Central 

    Google Scholar
     

  • Sosdian, S. M. et al. Constraining the evolution of Neogene ocean carbonate chemistry using the boron isotope pH proxy. Earth Planet. Sci. Lett. 498, 362–376 (2018).

    Article 
    ADS 
    CAS 

    Google Scholar
     

  • de la Vega, E., Chalk, T. B., Wilson, P. A., Bysani, R. P. & Foster, G. L. Atmospheric CO2 during the mid-Piacenzian warm period and the M2 glaciation. Sci. Rep. 10, 11002 (2020).

    Article 
    ADS 
    PubMed 
    PubMed Central 

    Google Scholar
     

  • Yamamoto, M. et al. Increased interglacial atmospheric CO2 levels followed the mid-Pleistocene Transition. Nat. Geosci. 15, 307–313 (2022).

    Article 
    ADS 
    CAS 

    Google Scholar
     

  • van de Wal, R. S. W., de Boer, B., Lourens, L. J., Köhler, P. & Bintanja, R. Reconstruction of a continuous high-resolution CO2 record over the past 20 million years. Clim. Past 7, 1459–1469 (2011).

    Article 

    Google Scholar
     

  • Stap, L. B. et al. CO2 over the past 5 million years: continuous simulation and new δ11B-based proxy data. Earth Planet. Sci. Lett. 439, 1–10 (2016).

    Article 
    ADS 
    CAS 

    Google Scholar
     

  • Berends, C. J., de Boer, B., Dolan, A. M., Hill, D. J. & van de Wal, R. S. W. Modelling ice sheet evolution and atmospheric CO2 during the Late Pliocene. Clim. Past 15, 1603–1619 (2019).

    Article 

    Google Scholar
     

  • Köhler, P. Atmospheric CO2 concentration based on boron isotopes versus simulations of the global carbon cycle during the Plio-Pleistocene. Paleoceanogr. Paleoclimatol. 38, e2022PA004439 (2023).

    Article 
    ADS 

    Google Scholar
     

  • Willeit, M., Ganopolski, A., Calov, R. & Brovkin, V. Mid-Pleistocene transition in glacial cycles explained by declining CO2 and regolith removal. Sci. Adv. 5, eaav7337 (2019).

    Article 
    ADS 
    CAS 
    PubMed 
    PubMed Central 

    Google Scholar
     

  • Köhler, P. & Munhoven, G. Late Pleistocene carbon cycle revisited by considering solid earth processes. Paleoceanogr. Paleoclimatol. 35, e2020PA004020 (2020).

    Article 
    ADS 

    Google Scholar
     

  • Jouzel, J. et al. Orbital and millennial Antarctic climate variability over the past 800,000 years. Science 317, 793–796 (2007).

    Article 
    ADS 
    CAS 
    PubMed 

    Google Scholar
     

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