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Abrupt changes in the global carbon cycle during the last glacial period

Abstract

During the last glacial period, atmospheric carbon dioxide (CO2) closely followed Antarctic temperature on millennial timescales. This strong correlation between Antarctic climate and atmospheric CO2 has led to suggestions that reorganizations of Southern Ocean circulation and/or biogeochemistry were the dominant cause of these variations. However, recent work also revealed centennial-scale changes in CO2 that appear unrelated to Antarctic climate and may represent additional modes of carbon cycle variability. Here we present a high-resolution CO2 record from the last glacial period from an ice core drilled in West Antarctica. This reconstruction precisely defines the timing of millennial and centennial CO2 variations with respect to Antarctic temperature and abrupt changes in Northern Hemisphere climate during Heinrich stadials and Dansgaard–Oeschger events. On the millennial scale, CO2 tracks Antarctic climate variability, but peak CO2 levels lag peak Antarctic temperature by more than 500 years. Centennial-scale CO2 increases of up to 10 ppm occurred within some Heinrich stadials, and increases of ~5 ppm occurred at the abrupt warming of most Dansgaard–Oeschger events. Regression analysis suggests that the CO2 variations can be explained by a combination of one mechanism operating on the timescale of Antarctic climate variability and a second responding on the timescale of Dansgaard–Oeschger events. Consistent with our statistical analysis, carbon cycle box-model simulations illustrate a plausible scenario where Southern Hemisphere processes contribute the majority of the CO2 variability during the last glacial period, but Northern Hemisphere processes are the crucial drivers of centennial-scale variability.

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Fig. 1: Ice-core records of polar climate, greenhouse gas variability and lead–lag correlations.
Fig. 2: Box-model experiments illustrating a plausible scenario for last glacial period CO2 variability.
Fig. 3: Centennial-scale greenhouse gas variability within Heinrich stadials.

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Data Availability

The WAIS Divide CO2 data are publicly available at the NOAA NCEI Database (https://www.ncdc.noaa.gov/paleo/study/31772) and US Antarctic Program Data Center (https://www.usap-dc.org/view/dataset/601337).

Code Availability

Model results are summarized in the supplemental material, and the entire suite of Monte Carlo simulations and box-model code is available from T.K.B. upon request.

References

  1. Dansgaard, W. et al. Evidence for general instability of past climate from a 250-kyr ice-core record. Nature 364, 218–220 (1993).

    Article  Google Scholar 

  2. Severinghaus, J. P. Timing of abrupt climate change at the end of the Younger Dryas interval from thermally fractionated gases in polar ice. Nature 391, 141–146 (1998).

    Article  Google Scholar 

  3. Huber, C. et al. Isotope calibrated Greenland temperature record over Marine Isotope Stage 3 and its relation to CH4. Earth Planet. Sci. Lett. 243, 504–509 (2006).

    Article  Google Scholar 

  4. Blunier, T. & Brook, E. J. Timing of millennial-scale climate change in Antarctica and Greenland during the last glacial period. Science 291, 109–112 (2001).

    Article  Google Scholar 

  5. Rhodes, R. H. et al. Enhanced tropical methane production in response to iceberg discharge in the North Atlantic. Science 348, 1016–1019 (2015).

    Article  Google Scholar 

  6. Stocker, T. S., Wright, D. G. & Broecker, W. S. The influence of high-latitude surface forcing on the global thermohaline circulation. Paleoceanography 7, 529–541 (1992).

    Article  Google Scholar 

  7. Crowley, T. J. North Atlantic deep water cools the Southern Hemisphere. Paleoceanography 7, 489–497 (1992).

    Article  Google Scholar 

  8. Broecker, W. S. Paleocean circulation during the last deglaciation: a bipolar seesaw? Paleoceanography 13, 119–121 (1998).

    Article  Google Scholar 

  9. Stocker, T. F. The seesaw effect. Science 282, 61–62 (1998).

    Article  Google Scholar 

  10. Barbante, C. et al. One-to-one coupling of glacial climate variability in Greenland and Antarctica. Nature 444, 195–198 (2006).

    Article  Google Scholar 

  11. WAIS Divide Project Members. Precise interpolar phasing of abrupt climate change during the last ice age. Nature 520, 661–665 (2015).

  12. Indermühle, A., Monnin, E., Stauffer, B., Stocker, T. F. & Wahlen, M. Atmospheric CO2 concentration from 60 to 20 kyr bp from the Taylor Dome ice core, Antarctica. Geophys. Res. Lett. 27, 735–738 (2000).

    Article  Google Scholar 

  13. Noone, D. & Simmonds, I. Sea ice control of water isotope transport to Antarctica and implications for ice core interpretation. J. Geophys. Res. 109, D07105 (2004).

    Google Scholar 

  14. Fischer, H. et al. The role of Southern Ocean processes in orbital and millennial CO2 variations—a synthesis. Quat. Sci. Rev. 29, 193–205 (2010).

    Article  Google Scholar 

  15. Wolff, E. W., Rankin, A. M. & Röthlisberger, R. An ice core indicator of Antarctic sea ice production? Geophys. Res. Lett. 30, 2158 (2003).

    Article  Google Scholar 

  16. Abram, N. J., Wolff, E. W. & Curran, M. A. J. A review of sea ice proxy information from polar ice cores. Quat. Sci. Rev. 79, 168–183 (2013).

    Article  Google Scholar 

  17. Stephens, B. B. & Keeling, R. F. The influence of Antarctic sea ice on glacial–interglacial CO2 variations. Nature 404, 171–174 (2001).

    Article  Google Scholar 

  18. Baumgartner, M. et al. High-resolution interpolar difference of atmospheric methane around the Last Glacial Maximum. Biogeosciences 9, 3961–3977 (2012).

    Article  Google Scholar 

  19. Ahn, J. & Brook, E. J. Atmospheric CO2 and climate on millennial time scales during the Last Glacial Period. Science 322, 83–85 (2008).

    Article  Google Scholar 

  20. Bereiter, B. et al. Mode change of millennial CO2 variability during the last glacial cycle associated with a bipolar marine carbon seesaw. Proc. Natl Acad. Sci. USA 109, 9755–9760 (2012).

    Article  Google Scholar 

  21. Anderson, R. F. et al. Wind-driven upwelling in the Southern Ocean and the deglacial rise in atmospheric CO2. Science 323, 1443–1448 (2009).

    Article  Google Scholar 

  22. Skinner, L. C., Fallon, S., Waelbroeck, C., Michel, E. & Barker, S. Ventilation of the deep Southern Ocean and deglacial CO2 rise. Science 328, 1147–1151 (2010).

    Article  Google Scholar 

  23. Bauska, T. K. et al. Controls on millennial-scale atmospheric CO2 variability during the last glacial period. Geophys. Res. Lett. 45, 7731–7740 (2018).

    Article  Google Scholar 

  24. Ahn, J. & Brook, E. J. Siple Dome ice reveals two modes of millennial CO2 change during the last ice age. Nat. Commun. 5, 3723 (2014).

    Article  Google Scholar 

  25. Marcott, S. A. et al. Centennial-scale changes in the global carbon cycle during the last deglaciation. Nature 514, 616–619 (2014).

    Article  Google Scholar 

  26. Ahn, J., Brook, E. J., Schmittner, A. & Kreutz, K. Abrupt change in atmospheric CO2 during the last ice age. Geophys. Res. Lett. 39, L18711 (2012).

    Article  Google Scholar 

  27. Gottschalk, J. et al. Mechanisms of millennial-scale atmospheric CO2 change in numerical model simulations. Quat. Sci. Rev. 220, 30–74 (2019).

    Article  Google Scholar 

  28. Marchal, O. et al. Modelling the concentration of atmospheric CO2 during the Younger Dryas climate event. Clim. Dyn. 15, 341–354 (1999).

    Article  Google Scholar 

  29. 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, 689–708 (2005).

    Article  Google Scholar 

  30. Menviel, L., Spence, P. & England, M. H. Contribution of enhanced Antarctic Bottom Water formation to Antarctic warm events and millennial-scale atmospheric CO2 increase. Earth Planet. Sci. Lett. 413, 37–50 (2015).

    Article  Google Scholar 

  31. 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  Google Scholar 

  32. Sigl, M. et al. The WAIS Divide deep ice core WD2014 chronology—Part 2: annual-layer counting (0–31 ka bp). Clim. Past 12, 769–786 (2016).

    Article  Google Scholar 

  33. Buizert, C. et al. The WAIS Divide deep ice core WD2014 chronology—Part 1: methane synchronization (68–31 ka bp) and the gas age–ice age difference. Clim. Past 11, 153–173 (2015).

    Article  Google Scholar 

  34. North Greenland Ice Core Project members. High-resolution record of Northern Hemisphere climate extending into the last interglacial period. Nature 431, 147–151 (2004).

  35. McConnell, J. R. et al. Synchronous volcanic eruptions and abrupt climate change 17.7 ka plausibly linked by stratospheric ozone depletion. Proc. Natl. Acad. Sci. USA https://doi.org/10.1073/pnas.1705595114 (2017).

  36. Markle, B. R., Steig, E. J., Roe, G. H., Winckler, G. & McConnell, J. R. Concomitant variability in high-latitude aerosols, water isotopes and the hydrologic cycle. Nat. Geosci. 11, 853–859 (2018).

    Article  Google Scholar 

  37. Bender, M. et al. Climate correlations between Greenland and Antarctica during the past 100,000 years. Nature 372, 663–666 (1994).

    Article  Google Scholar 

  38. 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  Google Scholar 

  39. Marcott, S. A., Shakun, J. D., Clark, P. U. & Mix, A. C. A reconstruction of regional and global temperature for the past 11,300 years. Science 339, 1198–1201 (2013).

    Article  Google Scholar 

  40. Shakun, J. D. et al. Global warming preceded by increasing carbon dioxide concentrations during the last deglaciation. Nature 484, 49–54 (2012).

    Article  Google Scholar 

  41. WAIS Divide Project Members. Onset of deglacial warming in West Antarctica driven by local orbital forcing. Nature 500, 440–444 (2013).

  42. Henry, L. G. et al. North Atlantic ocean circulation and abrupt climate change during the last glaciation. Science 353, 470–474 (2016).

  43. 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, 834–837 (2004).

    Article  Google Scholar 

  44. Elsig, J. et al. Stable isotope constraints on Holocene carbon cycle changes from an Antarctic ice core. Nature 461, 507–510 (2009).

    Article  Google Scholar 

  45. Bereiter, B., Shackleton, S., Baggenstos, D., Kawamura, K. & Severinghaus, J. Mean global ocean temperatures during the last glacial transition. Nature 553, 39–44 (2018).

    Article  Google Scholar 

  46. Winterfeld, M. et al. Deglacial mobilization of pre-aged terrestrial carbon from degrading permafrost. Nat. Commun. 9, 3666 (2018).

    Article  Google Scholar 

  47. Chen, T. et al. Synchronous centennial abrupt events in the ocean and atmosphere during the last deglaciation. Science 349, 1537 (2015).

    Article  Google Scholar 

  48. Rae, J. W. B. et al. CO2 storage and release in the deep Southern Ocean on millennial to centennial timescales. Nature 562, 569–573 (2018).

    Article  Google Scholar 

  49. Menviel, L. et al. Southern Hemisphere westerlies as a driver of the early deglacial atmospheric CO2 rise. Nat. Commun. 9, 2503 (2018).

    Article  Google Scholar 

  50. Severinghaus, J. P. Low-res δ15N and δ18O of O2 in the WAIS Divide 06A Deep Core (USAP, 2015); https://doi.org/10.7265/N5S46PWD

  51. 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).

    Article  Google Scholar 

  52. Anderson, R. F. et al. Biological response to millennial variability of dust and nutrient supply in the Subantarctic South Atlantic Ocean. Philos. Trans. A 372, 20130054 (2014).

    Article  Google Scholar 

  53. Lamy, F. et al. Increased dust deposition in the Pacific Southern Ocean during glacial periods. Science 343, 403–407 (2014).

    Article  Google Scholar 

  54. Jaccard, S. L., Galbraith, E. D., Martínez-García, A. & Anderson, R. F. Covariation of deep Southern Ocean oxygenation and atmospheric CO2 through the last ice age. Nature 530, 207–210 (2016).

    Article  Google Scholar 

  55. Levine, J. G., Yang, X., Jones, A. E. & Wolff, E. W. Sea salt as an ice core proxy for past sea ice extent: a process-based model study. J. Geophys. Res. Atmos. 119, 5737–5756 (2014).

    Article  Google Scholar 

  56. Stocker, T. F. & Johnsen, S. J. A minimum thermodynamic model for the bipolar seesaw. Paleoceanography 18, 4 (2003).

    Article  Google Scholar 

  57. Bauska, T. K. et al. Links between atmospheric carbon dioxide, the land carbon reservoir and climate over the past millennium. Nat. Geosci. 8, 383–387 (2015).

    Article  Google Scholar 

  58. Monnin, E. et al. Atmospheric CO2 concentrations over the last glacial termination. Science 291, 112–114 (2001).

    Article  Google Scholar 

  59. Schmitt, J. et al. Carbon isotope constraints on the deglacial CO2 rise from ice cores. Science 336, 711–714 (2012).

    Article  Google Scholar 

  60. 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  Google Scholar 

  61. Neff, P. D. A review of the brittle ice zone in polar ice cores. Ann. Glaciol. 55, 72–82 (2014).

    Article  Google Scholar 

Download references

Acknowledgements

This work was funded by NSF grant 0944764 to E.J.B. and Royal Society University Research Fellowship (grant URF\R1\180366) to T.K.B. We thank M. Kalk and T. Alig for assistance in measuring the CO2 data. We appreciate the support of the WAIS Divide Science Coordination Office at the Desert Research Institute (DRI) of Reno, Nevada, and the University of New Hampshire for the collection and distribution of the WAIS Divide ice core and related tasks (NSF grants 0230396, 0440817, 0944348 and 0944266). Additional support for this research came from the NSF Office of Polar Programs through their support of the Ice Drilling Program Office and the Ice Drilling Design and Operations group; the US National Ice Core Laboratory, for curation of the core; and the 109th New York Air National Guard, for airlift to Antarctica.

Author information

Authors and Affiliations

Authors

Contributions

T.K.B. and S.A.M. contributed equally. E.J.B. and S.A.M. designed the study. S.A.M. measured the CO2 data and performed the preliminary analysis. T.K.B. performed time series and modelling analyses and led the writing of the paper with input from S.A.M. and E.J.B.

Corresponding authors

Correspondence to Thomas K. Bauska or Shaun A. Marcott.

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The authors declare no competing interests.

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Peer review information Nature Geoscience thanks Julia Gottschalk and the other, anonymous, reviewer(s) for their contribution to the peer review of this work. Primary Handling Editor: James Super.

Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Extended data

Extended Data Fig. 1 A comparison of the WD to other ice core records of atmospheric CO2.

A comparison of ice core CO2 records including WD (this study), Byrd19, Taylor Glacier23,38, Talos Dome20, EDC (mechanical crushing58 and sublimation data59), Siple Dome24,26 and EDML20. All the ice core records have been smoothed with splines to preserve the millennial-scale variability and then subtracted from the WD record to show any offsets. Note that millennial-scale differences in the CO2 offset are susceptible to small errors in the various ice core chronologies (AICC2012) relative to the WD2014. Sub-panels show the raw data for each individual core record.

Extended Data Fig. 2 Mean differences in ice core CO2 relative to the WD Record.

*Note only plateaus in CO2 used for comparison **Original Taylor Dome12 timescale is too uncertain to quantify millennial-scale offsets. See Neff, 2014 for details on site data61.

Extended Data Fig. 3 Lead-lag correlation analysis of ice core data with percentile ranges.

Median and confidence intervals reported in years.

Extended Data Fig. 4 Alternative lead-lag analysis using one-box models with variable e-folding timescales.

The results of correlation of the various ice core proxy time-series against atmospheric CO2 after being passed through a series of one-box models. The x-axis shows the variable e-folding timescales of each run. Shading shows the uncertainty introduced from Monte Carlo error estimates in the delta-age history (90% CI) as in Fig. 1b (main text). The maximum reached in each curve indicates the apparent lead-lag with the horizontal bars indicate the range in maximum R2 values from the delta-age histories.

Extended Data Fig. 5 T-test and correlation analysis of CO2 response at onset of DO interstadials.

Individual interstadials are indicated with black marker and are labeled such that interstadials after an H-event are in blue and all others are labeled in grey. Grey shading shows the 95% confidence interval for the fits of the linear regressions.

Extended Data Fig. 6 Objective construction of the model ensemble solution.

Left panel. The forcings that enter the model with variable scaling (AABW formation scaled to WD-δ18O Antarctic sea-ice extent scaled to the log of WD Na, Subantarctic PO4 scaled to WD-Ca, and NADW formation scaled to Bermuda Rise Pa/Th, not shown Antarctic PO4 scaled to a combination of WD-Ca and sea ice extent). The maximum possible forcing is shown with the dotted red line along with the associated model response of atmospheric CO2 (black line). The red shading shows the range of forcings (mean and 1-sigma) that produce model predictions consistent with the ice core data (that is the ‘combined scenario’). The middle panel shows the same 1-sigma range for temperature forcings in the ‘combined scenario’. The right panel shows various model predictions including those that are used to select the ‘combined scenario’ constraint: atmospheric CO2, atmospheric δ13C-CO2 (including spline-smoothed data from refs. 44,59,60) and mean ocean temperature (MOT). All model results are slightly offset to match interglacial values in the data. Blue bars show the temporal range used in for each data constraint.

Extended Data Fig. 7 Maximum Proxy-to-Forcing Scaling Parameters and Maximum Predicted Changes in CO2.

*SST forcing is applied in the surface boxes but for convenience we report the predicted changes in mean ocean temperature (MOT).

Extended Data Fig. 8 Maximum effect of the major forcings in the full model ensemble.

The upper limit of forcings that enter the model prior to RMSE fitting are plotted on the left axes with the exception of temperature which is shown as the predicted change in MOT for the mean changes in temperature. The colours of the axes correspond to the colour of the trace (AABW = blue; Southern Ocean phosphate = orange; NADW = purple; temperature = grey). The corresponding predicted changes in CO2 to are plotted against the shown on the right axes in black. The figure is divided between the last glacial period on the left and the deglaciation on the right with larger ranges for all vertical axes during the deglaciation.

Extended Data Fig. 9 Lead-lag correlation analysis of model forcing and predicted CO2.

Lead-lag correlations for all model factorial experiments in which CO2 is driven soley by one forcing and lead-lag analysis of the combined scenario with forcings inputs from WD δ18O and NGRIP δ18O combined scenario.

Extended Data Fig. 10 Lead-lag analysis of model forcing and predictions with comparison to observations.

Left panel. Lead-lag correlation of factorial model experiments between proxy forcing and simulated CO2. Factorial experiments include: AABW formation (dark blue); ‘Iron Fertilization’/nutrient utilization (yellow); Antarctic sea ice extent (light blue); NADW formation (red); North Atlantic temperature (purple). Right panel. Lead-lag correlation of the WD-δ18O (dash dark blue) and NGRIP- δ18O (dashed purple) that enter the model as forcings against simulated CO2 in the ‘combined scenario’. This mimics the lead-lag correlation performed on the real ice core data and presented in the main body of the text between WD-CO2 and WD- δ18O (shaded blue envelope) and WD-δ18O and NGRIP-δ18O (shaded purple envelope).

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Summary of box-model results.

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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). https://doi.org/10.1038/s41561-020-00680-2

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