1. Broecker, W. S. Glacial to interglacial changes in ocean chemistry. Prog. Oceanogr. 11, 151–197 (1982).

2. Sarmiento, J. L. & Toggweiler, J. R. A new model for the role of the oceans in determining atmospheric pCO 2 . Nature 308, 621–624 (1984).

3. Sigman, D. M., Hain, M. P. & Haug, G. H. The polar ocean and glacial cycles in atmospheric CO 2 concentration. Nature 466, 47–55 (2010).

4. Burke, A. & Robinson, L. F. The Southern Ocean’s role in carbon exchange during the last deglaciation. Science 335, 557–561 (2012).

5. Roberts, J. et al. Evolution of South Atlantic density and chemical stratification across the last deglaciation. Proc. Natl Acad. Sci. USA 113, 514–519 (2016).

6. Martinez-Garcia, A. et al. Iron fertilization of the Subantarctic Ocean during the last ice age. Science 343, 1347–1350 (2014).

7. Yu, J. et al. Deep South Atlantic carbonate chemistry and increased interocean deep water exchange during last deglaciation. Quat. Sci. Rev. 90, 80–89 (2014).

8. Rae, J. W. B. et al. Deep water formation in the North Pacific and deglacial CO2 rise. Paleoceanography 29, 645–667 (2014).

9. Yu, J. et al. Responses of the deep ocean carbonate system to carbon reorganization during the last glacial–interglacial cycle. Quat. Sci. Rev. 76, 39–52 (2013).

10. Rickaby, R. E. M., Elderfield, H., Roberts, N., Hillenbrand, C. D. & Mackensen, A. Evidence for elevated alkalinity in the glacial Southern Ocean. Paleoceanography 25, PA1209 (2010).

11. Ferrari, R. et al. Antarctic sea ice control on ocean circulation in present and glacial climates. Proc. Natl Acad. Sci. USA 111, 8753–8758 (2014).

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

13. Adkins, J. F., McIntyre, K. & Schrag, D. P. The salinity, temperature, and δ18O of the glacial deep ocean. Science 298, 1769–1773 (2002).

14. Burke, A., Stewart, A. L., Adkins, J. F. & Ferrari, R. The glacial mid-depth radiocarbon bulge and its implications for the overturning circulation. Paleoceanography 30, 1021–1039 (2015).

15. Charles, C. D. et al. Millennial scale evolution of the Southern Ocean chemical divide. Quat. Sci. Rev. 29, 399–409 (2010).

16. Jaccard, S. L., Galbraith, E. D., Martinez-Garcia, A. & Anderson, R. F. Covariation of deep Southern Ocean oxygenation and atmospheric CO 2 through the last ice age. Nature 530, 207–210 (2016).

17. Stephens, B. B. & Keeling, R. F. The influence of Antarctic sea ice on glacial-interglacial CO 2 variations. Nature 404, 171–174 (2000).

18. Wolff, E. W. et al. Southern Ocean sea-ice extent, productivity and iron flux over the past eight glacial cycles. Nature 440, 491–496 (2006).

19. 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).

20. Galbraith, E. & de Lavergne, C. Response of a comprehensive climate model to a broad range of external forcings: relevance for deep ocean ventilation and the development of late Cenozoic ice ages. Clim. Dyn. https://doi.org/10.1007/s00382-018-4157-8 (2018).

21. Ahn, J. & Brook, E. J. Atmospheric CO 2 and climate on millennial time scales during the last glacial period. Science 322, 83–85 (2008).

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

23. Anderson, R. F. et al. Wind-driven upwelling in the Southern Ocean and the deglacial rise in atmospheric CO 2 . Science 323, 1443–1448 (2009).

24. Abernathey, R. & Ferreira, D. Southern Ocean isopycnal mixing and ventilation changes driven by winds. Geophys. Res. Lett. 42, 10,357–10,365 (2015).

25. Chen, T. et al. Synchronous centennial abrupt events in the ocean and atmosphere during the last deglaciation. Science 349, 1537–1541 (2015).

26. Martínez-Botí, M. A. et al. Boron isotope evidence for oceanic carbon dioxide leakage during the last deglaciation. Nature 518, 219–222 (2015).

27. Broecker, W. S., Bond, G., Klas, M., Bonani, G. & Wolfli, W. A salt oscillator in the glacial Atlantic? 1. The concept. Paleoceanography 5, 469–477 (1990).

28. Members, W. D. P. et al. Precise interpolar phasing of abrupt climate change during the last ice age. Nature 520, 661–665 (2015).

29. Markle, B. R. et al. Global atmospheric teleconnections during Dansgaard-Oeschger events. Nat. Geosci. 10, 36–40 (2017).

30. Köhler, P., Knorr, G. & Bard, E. Permafrost thawing as a possible source of abrupt carbon release at the onset of the Bølling/Allerød. Nat. Commun. 5, 5520 (2014).

31. Galbraith, E. D. & Eggleston, S. A lower limit to atmospheric CO 2 concentrations over the past 800,000 years. Nat. Geosci. 10, 295–298 (2017).

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

33. Keeling, R. F. & Stephens, B. B. Antarctic sea ice and the control of Pleistocene climate instability. Paleoceanography 16, 112–131 (2001).

34. Key, R. M. et al. Global Ocean Data Analysis Project, Version 2 (GLODAPv2). http://doi.org/10.3334/CDIAC/OTG.NDP093_GLODAPv2 (2015).

35. Olsen, A. et al. The Global Ocean Data Analysis Project version 2 (GLODAPv2)—an internally consistent data product for the world ocean. Earth Syst. Sci. Data 8, 297–323 (2016).

36. Bereiter, B. et al. Revision of the EPICA Dome C CO 2 record from 800 to 600 kyr before present. Geophys. Res. Lett. 42, 542–549 (2015).

37. Burke, A. et al. Reconnaissance dating: A new radiocarbon method applied to assessing the temporal distribution of Southern Ocean deep-sea corals. Deep Sea Res. Part I Oceanogr. Res. Pap. 57, 1510–1520 (2010).

38. Margolin, A. R. et al. Temporal and spatial distributions of cold-water corals in the Drake Passage: Insights from the last 35,000 years. Deep Sea Res. Part II Top. Stud. Oceanogr. 99, 237–248 (2014).

39. Spooner, P. T., Chen, T., Robinson, L. F. & Coath, C. Rapid uranium-series age screening of carbonates by laser ablation mass spectrometry. Quat. Geochronol. 31, 28–39 (2016).

40. Sinclair, D. J., Kinsley, L. P. & McCulloch, M. T. High resolution analysis of trace elements in corals by laser ablation ICP-MS. Geochim. Cosmochim. Acta 62, 1889–1901 (1998).

41. Robinson, L. F. et al. Primary U distribution in scleractinian corals and its implications for U series dating. Geochem. Geophys. Geosyst. 7, Q05022 (2006).

42. Gagnon, A. C., Adkins, J. F., Fernandez, D. P. & Robinson, L. F. Sr/Ca and Mg/Ca vital effects correlated with skeletal architecture in a scleractinian deep-sea coral and the role of Rayleigh fractionation. Earth Planet. Sci. Lett. 261, 280–295 (2007).

43. Rollion-Bard, C., Chaussidon, M. & France-Lanord, C. Biological control of internal pH in scleractinian corals: Implications on paleo-pH and paleo-temperature reconstructions. C. R. Geosci. 343, 397–405 (2011).

44. Stewart, J. A., Anagnostou, E. & Foster, G. L. An improved boron isotope pH proxy calibration for the deep-sea coral Desmophyllum dianthus through sub-sampling of fibrous aragonite. Chem. Geol. 447, 148–160 (2016).

45. Boyle, E. A. Cadmium, zinc, copper, and barium in foraminifera tests. Earth Planet. Sci. Lett. 53, 11–35 (1981).

46. Barker, S., Greaves, M. & Elderfield, H. A study of cleaning procedures used for foraminiferal Mg/Ca paleothermometry. Geochem. Geophys. Geosyst. 4, 8407 (2003).

47. Rae, J. W. B., Foster, G. L., Schmidt, D. N. & Elliott, T. Boron isotopes and B/Ca in benthic foraminifera: Proxies for the deep ocean carbonate system. Earth Planet. Sci. Lett. 302, 403–413 (2011).

48. Foster, G. L. et al. Interlaboratory comparison of boron isotope analyses of boric acid, seawater and marine CaCO 3 by MC-ICPMS and NTIMS. Chem. Geol. 358, 1–14 (2013).

49. Kiss, E. Ion-exchange separation and spectrophotometric determination of boron in geological materials. Anal. Chim. Acta 211, 243–256 (1988).

50. Lemarchand, D., Gaillardet, J., Göpel, C. & Manhès, G. An optimized procedure for boron separation and mass spectrometry analysis for river samples. Chem. Geol. 182, 323–334 (2002).

51. Foster, G. L. Seawater pH, pCO 2 and [CO 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).

52. Al-Ammar, A. S., Gupta, R. K. & Barnes, R. M. Elimination of boron memory effect in inductively coupled plasma-mass spectrometry by ammonia gas injection into the spray chamber during analysis. Spectrochim. Acta B At. Spectrosc. 55, 629–635 (2000).

53. Misra, S., Owen, R., Kerr, J. & Greaves, M. Determination of δ11B by HR-ICP-MS from mass limited samples: application to natural carbonates and water samples. Geochim. Cosmochim. Acta 140, 531–552 (2014).

54. Rae, J. W. B. in Boron Isotopes 107–143 (Springer, 2018).

55. McCulloch, M. T. et al. in Boron Isotopes 145–162 (Springer, 2018).

56. Anagnostou, E., Huang, K. F., You, C. F., Sikes, E. L. & Sherrell, R. M. Evaluation of boron isotope ratio as a pH proxy in the deep sea coral Desmophyllum dianthus: evidence of physiological pH adjustment. Earth Planet. Sci. Lett. 349-350, 251–260 (2012).

57. Trotter, J. et al. Quantifying the pH ‘vital effect’ in the temperate zooxanthellate coral Cladocora caespitosa: validation of the boron seawater pH proxy. Earth Planet. Sci. Lett. 303, 163–173 (2011).

58. Venn, A. A. et al. Impact of seawater acidification on pH at the tissue-skeleton interface and calcification in reef corals. Proc. Natl Acad. Sci. USA 110, 1634–1639 (2013).

59. Allison, N., Cohen, I., Finch, A. A., Erez, J. & Tudhope, A. W. Corals concentrate dissolved inorganic carbon to facilitate calcification. Nat. Commun. 5, 5741 (2014).

60. McCulloch, M. et al. Resilience of cold-water scleractinian corals to ocean acidification: Boron isotopic systematics of pH and saturation state up-regulation. Geochim. Cosmochim. Acta 87, 21–34 (2012).

61. Gagnon, A. C., Adkins, J. F., Erez, J. & Eiler, J. M. Sr/Ca sensitivity to aragonite saturation state in cultured subsamples from a single colony of coral: mechanism of biomineralization during ocean acidification. Geochim. Cosmochim. Acta 105, 240–254 (2013).