Centennial-scale changes in the global carbon cycle during the last deglaciation

Journal name:
Nature
Volume:
514,
Pages:
616–619
Date published:
DOI:
doi:10.1038/nature13799
Received
Accepted
Published online

Global climate and the concentration of atmospheric carbon dioxide (CO2) are correlated over recent glacial cycles1, 2. The combination of processes responsible for a rise in atmospheric CO2 at the last glacial termination1, 3 (23,000 to 9,000 years ago), however, remains uncertain1, 2, 3. Establishing the timing and rate of CO2 changes in the past provides critical insight into the mechanisms that influence the carbon cycle and helps put present and future anthropogenic emissions in context. Here we present CO2 and methane (CH4) records of the last deglaciation from a new high-accumulation West Antarctic ice core with unprecedented temporal resolution and precise chronology. We show that although low-frequency CO2 variations parallel changes in Antarctic temperature, abrupt CO2 changes occur that have a clear relationship with abrupt climate changes in the Northern Hemisphere. A significant proportion of the direct radiative forcing associated with the rise in atmospheric CO2 occurred in three sudden steps, each of 10 to 15 parts per million. Every step took place in less than two centuries and was followed by no notable change in atmospheric CO2 for about 1,000 to 1,500 years. Slow, millennial-scale ventilation of Southern Ocean CO2-rich, deep-ocean water masses is thought to have been fundamental to the rise in atmospheric CO2 associated with the glacial termination4, given the strong covariance of CO2 levels and Antarctic temperatures5. Our data establish a contribution from an abrupt, centennial-scale mode of CO2 variability that is not directly related to Antarctic temperature. We suggest that processes operating on centennial timescales, probably involving the Atlantic meridional overturning circulation, seem to be influencing global carbon-cycle dynamics and are at present not widely considered in Earth system models.

At a glance

Figures

  1. Greenhouse gas and stable water isotope measurements from Antarctica and Greenland.
    Figure 1: Greenhouse gas and stable water isotope measurements from Antarctica and Greenland.

    a, Oxygen isotopes from WDC11 (grey; black line is 11-point weighted average) and water-isotope-derived temperature composite from East Antarctica5 (green). δ18O = (18O/16O)sample/(18O/16O)VSMOW – 1; VSMOW, Vienna Standard Mean Ocean Water. b, Atmospheric CO2 concentrations (this study; black line is 5-point weighted average). c, Direct radiative forcing of CO2, CH4 and N2O (ref. 31) using a simplified expression32. d, Atmospheric CH4 concentrations (this study and ref. 11). e, Oxygen isotope measurements from the North Greenland Ice Project6 (NGRIP). Coloured bands at bottom indicate times when CO2 is stable (blue), slowly increasing (pink) or rapidly increasing (red), as described in the text. LGM, Last Glacial Maximum; HS1, Heinrich stadial 1 (~18.0–14.6 kyr ago); B/A, Bølling–Allerød; YD, Younger Dryas; Hol, Holocene.

  2. WAIS Divide CO2 and CH4 data plotted against multiple environmental proxies.
    Figure 2: WAIS Divide CO2 and CH4 data plotted against multiple environmental proxies.

    a, b, WAIS Divide CH4 (a) and CO2 (b). c, Iceberg discharge indices from the North Atlantic23 (15-record composite; normalized units). IRD, ice-rafted debris. d, e, Biological flux proxies from the Southern Ocean18 (d; TN57-13PC and E27-23) and off New Zealand25 (e; MD97-2120). f, g, Precipitation indices in speleothem records from Borneo26 (f) and Hulu27 (g). h, Carbon isotopes of CO2 (line with 1σ uncertainty band) from a multi-core composite4 placed on an updated chronology5. δ13C = (13C/12C)sample/(13C/12C)VPDB – 1; VPDB, Vienna PeeDee Belemnite. i, An AMOC proxy19 (GGC5). All age models that use radiocarbon dates were recalibrated with IntCal13 and updated (Supplementary Data). Coloured bands at bottom of plot indicate times when CO2 is stable (blue), slowly increasing (pink) or rapidly increasing (red), as described in the text. The grey and brown bands denote the timing of notable climatic transitions (for example LGM to HS1).

  3. Detailed view of greenhouse gas and stable isotope measurements from WDC.
    Figure 3: Detailed view of greenhouse gas and stable isotope measurements from WDC.

    Oxygen isotope measurements from WDC11 (black line is 11-point weighted average), water-isotope-derived temperature composite from East Antarctica5 (green), and atmospheric CH4 (purple) and CO2 concentrations (black line is 5-point weighted average) across the abrupt CO2 transition at 16.3 (a), 14.8 (b) and 11.7 kyr ago (c). Purple bands represent the durations of the abrupt CO2 transition and orange lines show their magnitudes (durations and magnitudes also in parentheses; Extended Data Table 1).

  4. [dgr]15N and the ice-age/gas-age difference for the WDC.
    Extended Data Fig. 1: δ15N and the ice-age/gas-age difference for the WDC.

    a, Borehole calibrated surface temperature reconstruction derived from δ18O measurements from the ice1. b, Accumulation rates reconstructed with the firn-densification inverse model (red curve) and from layer thickness observations (black curve). c, δ15N-N2 data for the upper 2,800 m (black dots) with model fit (green curve). d, Modelled age using firn-densification model (orange curve) and Δage estimate using the depth-difference technique from Parrenin et al.5 (black curve).

  5. CO2 concentrations and elemental data for WDC.
    Extended Data Fig. 2: CO2 concentrations and elemental data for WDC.

    WDC CO2 concentrations (blue) plotted against non-seasalt calcium (nssCa) concentrations (black) and hydrogen peroxide (H2O2, red) at multiple depths in the core where we observe abrupt changes in carbon dioxide. Hydrogen peroxide concentrations have been smoothed (2 m centred average) from original data to improve clarity.

  6. CO2 concentrations for WDC and EDC.
    Extended Data Fig. 3: CO2 concentrations for WDC and EDC.

    WDC CO2 concentrations on layer-counted (blue; 5-point weighted average) timescale and EPICA Dome C (EDC) CO2 concentrations on the Lemieux-Dudon et al.9, 14, 54 (brown), Parrenin et al.5 (red) and Antarctic ice-core chronology58, 59 (AICC2012; green) timescales.

  7. Calculated [Dgr]age offsets across the last deglacial termination for five ice cores from Antarctica and Greenland, compared with WDC.
    Extended Data Fig. 4: Calculated Δage offsets across the last deglacial termination for five ice cores from Antarctica and Greenland, compared with WDC.

    EDML, EPICA Dronning Maud Land; TALDICE, Talos Dome Ice; NGRIP, North Greenland Ice Project. Ice-core data from refs 58, 59.

  8. Firn smoothing functions applied to CO2 data from WDC and EDC.
    Extended Data Fig. 5: Firn smoothing functions applied to CO2 data from WDC and EDC.

    a, The red line is the Green’s function (smoothing function) produced by a firn model using an assumed EDC accumulation rate of 0.015 m yr−1 and a temperature of 209 K. b, CO2 data from WDC (dots) and EDC (dots) plotted against artificially smoothed CO2 data from WDC using the EDC firn smoothing function (red line in both plots). WDC data have been systematically lowered by 4 p.p.m. for direct comparison with EDC.

  9. Simple box model source history and atmospheric CO2 response compared to measured data from WDC.
    Extended Data Fig. 6: Simple box model source history and atmospheric CO2 response compared to measured data from WDC.

    a, Applied source history used in the modelling experiment. b, Atmospheric CO2 record from WDC (5-point weighted average; blue) and the model derived atmospheric history (black). Box model from ref. 55.

  10. CO2 concentrations and temperature reconstructions for the last deglaciation.
    Extended Data Fig. 7: CO2 concentrations and temperature reconstructions for the last deglaciation.

    WDC CO2 concentrations (purple; 5-point weighted average), a global temperature reconstruction2 (black; grey band is 1σ uncertainty envelope), and an Antarctic temperature stack based on stable isotopes from East Antarctic ice cores5 (red).

Tables

  1. Timing of five abrupt transitions in CO2 and CH4 during the last termination
    Extended Data Table 1: Timing of five abrupt transitions in CO2 and CH4 during the last termination

References

  1. Petit, J. R. et al. Climate and atmospheric history of the last 420,000 years from the Vostok ice core, Antarctica. Nature 399, 429436 (1999)
  2. Shakun, J. D. et al. Global warming preceded by increasing carbon dioxide concentrations during the last deglaciation. Nature 484, 4954 (2012)
  3. Sigman, D. M. & Boyle, E. A. Glacial/interglacial variations in atmospheric carbon dioxide. Nature 407, 859869 (2000)
  4. Schmitt, J. et al. Carbon isotope constraints on the deglacial CO2 rise from ice cores. Science 336, 711714 (2012)
  5. Parrenin, F. et al. Synchronous change of atmospheric CO2 and Antarctic temperature during the last deglacial warming. Science 339, 10601063 (2013)
  6. North Greenland Ice Core Project members. High-resolution record of Northern Hemisphere climate extending into the last interglacial period. Nature 431, 147151 (2004)
  7. Grootes, P. M., Stuiver, M., White, J. W. C., Johnsen, S. & Jouzel, J. Comparison of oxygen isotope records from the GISP2 and GRIP Greenland ice cores. Nature 366, 552554 (1993)
  8. 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. 102, 2657726582 (1997)
  9. Monnin, E. et al. Atmospheric CO2 concentrations over the last glacial termination. Science 291, 112114 (2001)
  10. Ahn, J. et al. A record of atmospheric CO2 during the last 40,000 years from the Siple Dome, Antarctica ice core. J. Geophys. Res. 109, D13305 (2004)
  11. WAIS Divide Project Members. Onset of deglacial warming in West Antarctica driven by local orbital forcing. Nature 500, 440444 (2013)
  12. Brook, E. J., Harder, S., Severinghaus, J., Steig, E. J. & Sucher, C. M. On the origin and timing of rapid changes in atmospheric methane during the last glacial period. Glob. Biogeochem. Cycles 14, 559572 (2000)
  13. Khalil, M. A. K. & Rasmussen, R. A. Sources, sinks, and seasonal cycles of atmospheric methane. J. Geophys. Res. 88, 51315144 (1983)
  14. Lourantou, A., Chappellaz, J., Barnola, J. M., Masson-Delmotte, V. & Raynaud, D. Changes in atmospheric CO2 and its carbon isotopic ratio during the penultimate deglaciation. Quat. Sci. Rev. 29, 19831992 (2010)
  15. Broecker, W. S. Glacial to interglacial changes in ocean chemistry. Prog. Oceanogr. 11, 151197 (1982)
  16. Sigman, D. M., de Boer, A. M. & Haug, G. H. in Ocean Circulation: Mechanisms and Impacts (eds Schmittner, A., Chiang, J. C. H. & Hemming, S. R.) 335349 (American Geophysical Union, 2007)
  17. Chiang, J. C. H. & Bitz, C. M. Influence of high latitude ice cover on the marine intertropical convergence zone. Clim. Dyn. 25, 477496 (2005)
  18. Anderson, R. F. et al. Wind-driven upwelling in the Southern Ocean and the deglacial rise in atmospheric CO2. Science 323, 14431448 (2009)
  19. McManus, J. F., Francois, R., Gherardi, J.-M., Keigwin, L. D. & Brown-Leger, S. Collapse and rapid resumption of Atlantic meridional circulation linked to deglacial climate changes. Nature 428, 834837 (2004)
  20. Schmittner, A. & Galbraith, E. D. Glacial greenhouse-gas fluctuations controlled by ocean circulation changes. Nature 456, 373376 (2008)
  21. Köhler, P., Joos, F., Gerber, S. & Knutti, R. Simulated changes in vegetation distribution, land carbon storage, and atmospheric CO2 in response to a collapse of the North Atlantic thermohaline circulation. Clim. Dyn. 25, 689708 (2005)
  22. Köhler, P., Knorr, G., Buiron, D., Lourantou, A. & Chappellaz, J. Abrupt rise in atmospheric CO2 at the onset of the Bølling/Allerød: in-situ ice core data versus true atmospheric signals. Clim. Past 7, 473486 (2011)
  23. Stern, J. V. & Lisiecki, L. E. North Atlantic circulation and reservoir age changes over the past 41,000 years: North Atlantic reservoir age history. Geophys. Res. Lett. 40, 36933697 (2013)
  24. Toggweiler, J. R., Russell, J. L. & Carson, S. R. Midlatitude westerlies, atmospheric CO2, and climate change during the ice ages. Paleoceanography 21, PA2005 (2006)
  25. Sachs, J. P. & Anderson, R. F. Increased productivity in the subantarctic ocean during Heinrich events. Nature 434, 11181121 (2005)
  26. Partin, J. W., Cobb, K. M., Adkins, J. F., Clark, B. & Fernandez, D. P. Millenial-scale trends in west Pacific warm pool hydrology since the Last Glacial Maximum. Nature 449, 452455 (2007)
  27. Wu, J., Wang, Y., Cheng, H. & Edwards, L. R. An exceptionally strengthened East Asian summer monsoon event between 19.9 and 17.1 ka BP recorded in a Hulu stalagmite. Sci. China Ser. Earth Sci. 52, 360368 (2009)
  28. Stager, J. C., Ryves, D. B., Chase, B. M. & Pausata, F. S. R. Catastrophic drought in the Afro-Asian monsoon region during Heinrich event 1. Science 331, 12991302 (2011)
  29. Scholze, M., Knorr, W. & Heimann, M. Modelling terrestrial vegetation dynamics and carbon cycling for an abrupt climatic change event. Holocene 13, 327333 (2003)
  30. Weber, M. E. et al. Millennial-scale variability in Antarctic ice-sheet discharge during the last deglaciation. Nature 510, 134138 (2014)
  31. Schilt, A. et al. Atmospheric nitrous oxide during the last 140,000 years. Earth Planet. Sci. Lett. 300, 3343 (2010)
  32. Ramaswamy, V. et al. Climate Change 2001: The Scientific Basis (eds Houghton, J. T. et al.) 349416 (Cambridge Univ. Press, 2001)
  33. Ahn, J., Brook, E. J. & Howell, K. A high-precision method for measurement of paleoatmospheric CO2 in small polar ice samples. J. Glaciol. 55, 499506 (2009)
  34. Ahn, J. et al. Atmospheric CO2 over the last 1000 years: a high-resolution record from the West Antarctic Ice Sheet (WAIS) Divide ice core. Glob. Biogeochem. Cycles 26, GB2027 (2012)
  35. Mitchell, L. E., Brook, E. J., Sowers, T., McConnell, J. R. & Taylor, K. Mulidecadal variability of atmospheric methane, 1000-1800 C.E. J. Geophys. Res. 116, G02007 (2011)
  36. Schwander, J. & Stauffer, B. Age difference between polar ice and the air trapped in its bubbles. Nature 311, 4547 (1984)
  37. Sowers, T., Bender, M., Raynaud, D. & Korotkevich, Y. S. δ15N of N2 in air trapped in polar ice: a tracer of gas transport in the firn and a possible constraint on ice age-gas age difference. J. Geophys. Res. 97, 1568315697 (1992)
  38. Sowers, T., Bender, M. & Raynaud, D. Elemental and isotopic composition of occluded O2 and N2 in polar ice. J. Geophys. Res. 94, 51375150 (1989)
  39. Petrenko, V. V., Severinghaus, J. P., Brook, E. J., Reeh, N. & Schaefer, H. Gas records from the West Greenland ice margin covering the Last Glacial Termination: a horizontal ice core. Quat. Sci. Rev. 25, 865875 (2006)
  40. Herron, M. M. & Langway, C. C. Firn densification: an empirical model. J. Glaciol. 93, 373383 (1980)
  41. Rasmussen, S. O. et al. A first chronology for the North Greenland Eemian Ice Drilling (NEEM) ice core. Clim. Past 9, 27132730 (2013)
  42. Kaspers, K. A. et al. Model calculations of the age of firn air across the Antarctic continent. Atmos. Chem. Phys. 4, 13651380 (2004)
  43. Battle, M. O. et al. Controls on the movement and composition of firn air at the West Antarctic Ice Sheet Divide. Atmos. Chem. Phys. 11, 1863318675 (2011)
  44. Cuffey, K. M. & Glow, G. D. Temperature, accumulation, and ice sheet elevation in central Greenland through the last deglacial transition. J. Geophys. Res. 102, 2638326396 (1997)
  45. Steig, E. J. et al. Recent climate and ice-sheet change in West Antarctica compared to the past 2000 years. Nature Geosci. 6, 372375 (2013)
  46. Hörhold, M. W. et al. On the impact of impurities on the densification of polar firn. Earth Planet. Sci. Lett. 325–326, 9399 (2012)
  47. Barnola, J. M., Pimienta, P., Raynaud, D. & Korotkevich, Y. S. CO2–climate relationship as deduced from the Vostok ice core: a reexamination based on new measurements and on a reevaluation of the air dating. Tellus B 43, 8390 (1991)
  48. Legrand, M. R. & Delmas, R. J. Soluble impurities in four Antarctic ice cores over the last 30,000 years. Ann. Glaciol. 10, 116120 (1988)
  49. Tschumi, J. & Stauffer, B. Reconstructing past atmospheric CO2 concentration based on ice-core analyses: open questions due to in situ production of CO2 in the ice. J. Glaciol. 46, 4553 (2000)
  50. Sofen, E. D. et al. WAIS Divide ice core suggests sustained changes in the atmospheric formation pathways of sulfate and nitrate since the 19th century in the extratropical Southern Hemisphere. Atmos. Chem. Phys. Discuss. 13, 2308923138 (2013)
  51. Lamarque, J.-F., McConnell, J. R., Shindell, D. T., Orlando, J. J. & Tyndall, G. S. Understanding the drivers for the 20th century change of hydrogen peroxide in Antarctic ice-cores. Geophys. Res. Lett. 38, L04810 (2011)
  52. Siegenthaler, U. et al. Supporting evidence from the EPICA Dronning Maud Land ice core for atmospheric CO2 change during the past millenium. Tellus B 57, 5157 (2005)
  53. Buizert, C. et al. Gas transport in firn: multiple-tracer characterisation and model intercomparison for NEEM, Northern Greenland. Atmos. Chem. Phys. Discuss. 11, 1597516021 (2011)
  54. Lemieux-Dudon, B. et al. Consistent dating of Antarctica and Greenland ice cores. Quat. Sci. Rev. 29, 820 (2010)
  55. Oeschger, H., Siegenthaler, U., Schotterer, U. & Gugelmann, A. A box diffusion model to study the carbon dioxide exchange in nature. Tellus 27, 168192 (1975)
  56. Mudelsee, M. Break function regression: a tool for quantifying trend changes in climate time series. Eur. Phys. J. Spec. Top. 174, 4963 (2009)
  57. Mudelsee, M. Ramp function regression: a tool for quantifying climate transitions. Comput. Geosci. 26, 293307 (2000)
  58. Veres, D. et al. Antarctic ice core chronology (AICC2012): an optimized multi-parameter and multi-site dating approach for the last 120 thousand years. Clim. Past 9, 17331748 (2013)
  59. Bazin, L. et al. An optimized multi-proxies, multi-site Antarctic ice and gas orbital chronology (AICC2012): 120-800 ka. Clim. Past 9, 17151731 (2013)

Download references

Author information

Affiliations

  1. College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, Oregon 97331, USA

    • Shaun A. Marcott,
    • Thomas K. Bauska,
    • Christo Buizert,
    • Julia L. Rosen,
    • Michael L. Kalk &
    • Edward J. Brook
  2. Department of Geoscience, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA

    • Shaun A. Marcott
  3. Department of Earth and Space Sciences, University of Washington, Seattle, Washington 98195, USA

    • Eric J. Steig &
    • T. J. Fudge
  4. Department of Geography, University of California, Berkeley, California 94720, USA

    • Kurt M. Cuffey
  5. Scripps Institution of Oceanography, University of California, San Diego, California 92037, USA

    • Jeffery P. Severinghaus
  6. School of Earth and Environmental Sciences, Seoul National University, Seoul 151-742, South Korea

    • Jinho Ahn
  7. Desert Research Institute, Nevada System of Higher Education, Reno, Nevada 89512, USA

    • Joseph R. McConnell &
    • Kendrick C. Taylor
  8. Earth and Environmental Systems Institute, Pennsylvania State University, University Park, Pennsylvania 16802, USA

    • Todd Sowers
  9. INSTAAR, University of Colorado, Boulder, Colorado 80309, USA

    • James W. C. White

Contributions

S.A.M. and E.J.B. oversaw and contributed to all aspects of the research, and with T.K.B. designed the project and led the writing of the paper. J.A., M.L.K., J.P.S. and T.S. assisted with and contributed WDC gas measurements. E.J.S. contributed the WDC water isotope data. J.R.M. contributed calcium and hydrogen peroxide concentration measurements. C.B. developed the gas chronology. J.L.R. performed the firn modelling experiments and interpretation. K.C.T. led the field effort that collected the samples. K.M.C., T.J.F., J.R.M., E.J.S., K.C.T. and J.W.C.W. developed the ice chronology and interpretation. All authors discussed the results and contributed input to the manuscript.

Competing financial interests

The authors declare no competing financial interests.

Corresponding author

Correspondence to:

Author details

Extended data figures and tables

Extended Data Figures

  1. Extended Data Figure 1: δ15N and the ice-age/gas-age difference for the WDC. (251 KB)

    a, Borehole calibrated surface temperature reconstruction derived from δ18O measurements from the ice1. b, Accumulation rates reconstructed with the firn-densification inverse model (red curve) and from layer thickness observations (black curve). c, δ15N-N2 data for the upper 2,800 m (black dots) with model fit (green curve). d, Modelled age using firn-densification model (orange curve) and Δage estimate using the depth-difference technique from Parrenin et al.5 (black curve).

  2. Extended Data Figure 2: CO2 concentrations and elemental data for WDC. (187 KB)

    WDC CO2 concentrations (blue) plotted against non-seasalt calcium (nssCa) concentrations (black) and hydrogen peroxide (H2O2, red) at multiple depths in the core where we observe abrupt changes in carbon dioxide. Hydrogen peroxide concentrations have been smoothed (2 m centred average) from original data to improve clarity.

  3. Extended Data Figure 3: CO2 concentrations for WDC and EDC. (283 KB)

    WDC CO2 concentrations on layer-counted (blue; 5-point weighted average) timescale and EPICA Dome C (EDC) CO2 concentrations on the Lemieux-Dudon et al.9, 14, 54 (brown), Parrenin et al.5 (red) and Antarctic ice-core chronology58, 59 (AICC2012; green) timescales.

  4. Extended Data Figure 4: Calculated Δage offsets across the last deglacial termination for five ice cores from Antarctica and Greenland, compared with WDC. (114 KB)

    EDML, EPICA Dronning Maud Land; TALDICE, Talos Dome Ice; NGRIP, North Greenland Ice Project. Ice-core data from refs 58, 59.

  5. Extended Data Figure 5: Firn smoothing functions applied to CO2 data from WDC and EDC. (103 KB)

    a, The red line is the Green’s function (smoothing function) produced by a firn model using an assumed EDC accumulation rate of 0.015 m yr−1 and a temperature of 209 K. b, CO2 data from WDC (dots) and EDC (dots) plotted against artificially smoothed CO2 data from WDC using the EDC firn smoothing function (red line in both plots). WDC data have been systematically lowered by 4 p.p.m. for direct comparison with EDC.

  6. Extended Data Figure 6: Simple box model source history and atmospheric CO2 response compared to measured data from WDC. (148 KB)

    a, Applied source history used in the modelling experiment. b, Atmospheric CO2 record from WDC (5-point weighted average; blue) and the model derived atmospheric history (black). Box model from ref. 55.

  7. Extended Data Figure 7: CO2 concentrations and temperature reconstructions for the last deglaciation. (145 KB)

    WDC CO2 concentrations (purple; 5-point weighted average), a global temperature reconstruction2 (black; grey band is 1σ uncertainty envelope), and an Antarctic temperature stack based on stable isotopes from East Antarctic ice cores5 (red).

Extended Data Tables

  1. Extended Data Table 1: Timing of five abrupt transitions in CO2 and CH4 during the last termination (141 KB)

Supplementary information

Excel files

  1. Supplementary Data (684 KB)

    This file contains Supplementary Data, which relates to the main paper.

Additional data