Abstract

The past two million years of eastern African climate variability is currently poorly constrained, despite interest in understanding its assumed role in early human evolution1,2,3,4. Rare palaeoclimate records from northeastern Africa suggest progressively drier conditions2,5 or a stable hydroclimate6. By contrast, records from Lake Malawi in tropical southeastern Africa reveal a trend of a progressively wetter climate over the past 1.3 million years7,8. The climatic forcings that controlled these past hydrological changes are also a matter of debate. Some studies suggest a dominant local insolation forcing on hydrological changes9,10,11, whereas others infer a potential influence of sea surface temperature changes in the Indian Ocean8,12,13. Here we show that the hydroclimate in southeastern Africa (20–25° S) is controlled by interplay between low-latitude insolation forcing (precession and eccentricity) and changes in ice volume at high latitudes. Our results are based on a multiple-proxy reconstruction of hydrological changes in the Limpopo River catchment, combined with a reconstruction of sea surface temperature in the southwestern Indian Ocean for the past 2.14 million years. We find a long-term aridification in the Limpopo catchment between around 1 and 0.6 million years ago, opposite to the hydroclimatic evolution suggested by records from Lake Malawi. Our results, together with evidence of wetting at Lake Malawi, imply that the rainbelt contracted toward the Equator in response to increased ice volume at high latitudes. By reducing the extent of woodland or wetlands in terrestrial ecosystems, the observed changes in the hydroclimate of southeastern Africa—both in terms of its long-term state and marked precessional variability—could have had a role in the evolution of early hominins, particularly in the extinction of Paranthropus robustus.

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References

  1. 1.

    Vrba, E. S. Environment and evolution: alternative causes of the temporal distribution of evolutionary events. S. Afr. J. Sci. 81, 229–236 (1985).

  2. 2.

    deMenocal, P. B. Plio-Pleistocene African climate. Science 270, 53–59 (1995).

  3. 3.

    Potts, R. Environmental hypotheses of hominin evolution. Yearb. Phys. Anthropol. 41, 93–136 (1998).

  4. 4.

    Maslin, M. A. & Trauth, M. H. in The First Humans: Origin and Early Evolution of the Genus Homo (eds Grine, F. E. et al.) 151–158 (Springer, New York, 2009).

  5. 5.

    Cerling, T. E. et al. Woody cover and hominin environments in the past 6 million years. Nature 476, 51–56 (2011).

  6. 6.

    Blumenthal, S. A. et al. Aridity and hominin environments. Proc. Natl Acad. Sci. USA 114, 7331–7336 (2017).

  7. 7.

    Lyons, R. P. et al. Continuous 1.3-million-year record of East African hydroclimate, and implications for patterns of evolution and biodiversity. Proc. Natl Acad. Sci. USA 112, 15568–15573 (2015).

  8. 8.

    Johnson, T. C. et al. A progressively wetter climate in southern East Africa over the past 1.3 million years. Nature 537, 220–224 (2016).

  9. 9.

    Partridge, T. C., Demenocal, P. B., Lorentz, S. A., Paiker, M. J. & Vogel, J. C. Orbital forcing of climate over South Africa: a 200,000-year rainfall record from the Pretoria saltpan. Quat. Sci. Rev. 16, 1125–1133 (1997).

  10. 10.

    Schefuß, E., Kuhlmann, H., Mollenhauer, G., Prange, M. & Pätzold, J. Forcing of wet phases in southeast Africa over the past 17,000 years. Nature 480, 509–512 (2011).

  11. 11.

    Simon, M. H. et al. Eastern South African hydroclimate over the past 270,000 years. Sci. Rep. 5, 18153 (2015).

  12. 12.

    Tierney, J. E. et al. Northern Hemisphere controls on tropical southeast African climate during the past 60,000 years. Science 322, 252–255 (2008).

  13. 13.

    Dupont, L. M. et al. Glacial–interglacial vegetation dynamics in South Eastern Africa coupled to sea surface temperature variations in the Western Indian Ocean. Clim. Past 7, 1209–1224 (2011).

  14. 14.

    Schefuß, E., Schouten, S. & Schneider, R. R. Climatic controls on central African hydrology during the past 20,000 years. Nature 437, 1003–1006 (2005).

  15. 15.

    Caley, T. et al. High-latitude obliquity as a dominant forcing in the Agulhas current system. Clim. Past 7, 1285–1296 (2011).

  16. 16.

    Castañeda, I. S. et al. Middle to Late Pleistocene vegetation and climate change in subtropical southern East Africa. Earth Planet. Sci. Lett. 450, 306–316 (2016).

  17. 17.

    Tyson, P. D. & Preston-Whyte, R. A. The Weather and Climate of Southern Africa (Oxford Univ. Press, Oxford, 2000).

  18. 18.

    Kutzbach, J. E., Liu, X., Liu, Z. & Chen, G. Simulation of the evolutionary response of global summer monsoons to orbital forcing over the past 280,000 years. Clim. Dyn. 30, 567–579 (2008).

  19. 19.

    Reason, C. J. C. Subtropical Indian Ocean SST dipole events and southern African rainfall. Geophys. Res. Lett. 28, 2225–2227 (2001).

  20. 20.

    McClymont, E. L., Sosdian, S. M., Rosell-Melé, A. & Rosenthal, Y. Pleistocene sea-surface temperature evolution: early cooling, delayed glacial intensification, and implications for the mid-Pleistocene climate transition. Earth Sci. Rev. 123, 173–193 (2013).

  21. 21.

    Elderfield, H. et al. Evolution of ocean temperature and ice volume through the mid-Pleistocene climate transition. Science 337, 704–709 (2012).

  22. 22.

    Pollard, D. & DeConto, R. M. Modelling West Antarctic ice sheet growth and collapse through the past five million years. Nature 458, 329–332 (2009).

  23. 23.

    Tierney, J. E., Smerdon, J. E., Anchukaitis, K. J. & Seager, R. Multidecadal variability in East African hydroclimate controlled by the Indian Ocean. Nature 493, 389–392 (2013).

  24. 24.

    Balter, V., Braga, J., Télouk, P. & Thackeray, J. F. Evidence for dietary change but not landscape use in South African early hominins. Nature 489, 558–560 (2012).

  25. 25.

    Henry, A. G. et al. The diet of Australopithecus sediba. Nature 487, 90–93 (2012).

  26. 26.

    Žliobaitė, I., Fortelius, M. & Stenseth, N. C. Reconciling taxon senescence with the Red Queen’s hypothesis. Nature 552, 92–95 (2017).

  27. 27.

    Foley, R. in African Biogeography, Climate Change, and Human Evolution (eds Bromage, T. G. & Schrenk, F.) 328–348 (Oxford Univ. Press, Oxford, 1999).

  28. 28.

    Xie, P. & Arkin, P. A. Global precipitation: a 17-year monthly analysis based on gauge observations, satellite estimates and numerical model outputs. Bull. Am. Meteorol. Soc. 78, 2539–2558 (1997).

  29. 29.

    Locarnini, R. A. et al. World Ocean Atlas 2009. Volume 1: Temperature (NOAA Atlas NESDIS 68, U.S. Government Printing Office, Washington, D.C., 2010).

  30. 30.

    Still, C. J. & Powell, R. L. in Isoscapes: Understanding Movement, Pattern, and Process on Earth through Isotope Mapping (eds West, J. B. et al.) 179–194 (Springer, Dordrecht, 2010).

  31. 31.

    Laskar, J. et al. A long-term numerical solution for the insolation quantities of the Earth. Astron. Astrophys. 428, 261–285 (2004).

  32. 32.

    Page, E. S. Continuous inspection schemes. Biometrika 41, 100–115 (1954).

  33. 33.

    García-Comas, C. et al. Zooplankton long-term changes in the NW Mediterranean Sea: decadal periodicity forced by winter hydrographic conditions related to large-scale atmospheric changes? J. Mar. Syst. 87, 216–226 (2011).

  34. 34.

    Ibanez, F., Fromentin, J. M. & Castel, J. Application of the cumulated function to the processing of chronological data in oceanography. C. R. Acad. Sci. III 316, 745–748 (1993).

  35. 35.

    Maher, L. J. Jr. Nomograms for computing 0.95 confidence limits of pollen data. Rev. Palaeobot. Palynol. 13, 85–93 (1972).

  36. 36.

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

  37. 37.

    Paillard, D., Labeyrie, L. D. & Yiou, P. AnalySeries 1.0: Macintosh program performs time-series analysis. Eos 77, 379 (1996).

  38. 38.

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

  39. 39.

    de Villiers, S., Greaves, M. & Elderfield, H. An intensity ratio calibration method for the accurate determination of Mg/Ca and Sr/Ca of marine carbonates by ICP-AES. Geochem. Geophys. Geosyst. 3, 2001GC000169 (2002).

  40. 40.

    Anand, P., Elderfield, H. & Conte, M. H. Calibration of Mg/Ca thermometry in planktonic foraminifera from a sediment trap time series. Paleoceanography 18, 1050 (2003).

  41. 41.

    Hemleben, C., Spindler, M. & Erson, O. R. Modern Planktonic Foraminifera (Springer, New York, 1989).

  42. 42.

    Kennett, J. P. & Srinivasan, M. S. Neogene Planktonic Foraminifera: A Phylogenetic Atlas (Hutchinson Ross, Stroudsburg, 1983).

  43. 43.

    Guiot, J. & de Vernal, A. in Proxies in Late Cenozoic Paleoceanography (eds Hillaire-Marcel, C. & de Vernal, A.) 523–563 (Elsevier, Amsterdam, 2007).

  44. 44.

    Kucera, M. in Proxies in Late Cenozoic Paleoceanography (eds Hillaire-Marcel, C. & de Vernal, A.) 213–262 (Elsevier, Amsterdam, 2007).

  45. 45.

    Barrows, T. T. & Juggins, S. Sea-surface temperatures around the Australian margin and Indian Ocean during the Last Glacial Maximum. Quat. Sci. Rev. 24, 1017–1047 (2005).

  46. 46.

    Kucera, M. et al. Reconstruction of sea-surface temperatures from assemblages of planktonic foraminifera: multi-technique approach based on geographically constrained calibration data sets and its application to glacial Atlantic and Pacific Oceans. Quat. Sci. Rev. 24, 951–998 (2005).

  47. 47.

    Von Storch, H. & Zwiers, F. W. Statistical Analysis in Climate Research (Cambridge Univ. Press, Cambridge, 1999).

  48. 48.

    Roche, D. M. δ18O water isotope in the iLOVECLIM model (version 1.0)–part 1: implementation and verification. Geosci. Model Dev. 6, 1481–1491 (2013).

  49. 49.

    Roche, D. M. & Caley, T. δ18O water isotope in the iLOVECLIM model (version 1.0)–part 2: evaluation of model results against observed δ18O in water samples. Geosci. Model Dev. 6, 1493–1504 (2013).

  50. 50.

    Caley, T. & Roche, D. M. δ18O water isotope in the iLOVECLIM model (version 1.0)–part 3: a palaeo-perspective based on present-day data–model comparison for oxygen stable isotopes in carbonates. Geosci. Model Dev. 6, 1505–1516 (2013).

  51. 51.

    Caley, T., Roche, D. M. & Renssen, H. Orbital Asian summer monsoon dynamics revealed using an isotope-enabled global climate model. Nat. Commun. 5, 5371 (2014).

  52. 52.

    Collins, J. A. et al. Rapid termination of the African Humid Period triggered by northern high-latitude cooling. Nat. Commun. 8, 1372 (2017).

  53. 53.

    Grine, F. E. & Daegling, D. J. Functional morphology, biomechanics and the retrodiction of early hominin diets. C. R. Palevol 16, 613–631 (2017).

  54. 54.

    Wood, B. & Schroer, K. in Human Paleontology and Prehistory. Contributions in Honor of Yoel Rak (eds Marom, A. & Hovers, E.) 95–107 (Springer, Cham, 2017).

  55. 55.

    Patterson, D. B., Faith, J. T., Bobe, R. & Wood, B. Regional diversity patterns in African bovids, hyaenids, and felids during the past 3 million years: the role of taphonomic bias and implications for the evolution of Paranthropus. Quat. Sci. Rev. 96, 9–22 (2014).

  56. 56.

    Grine, F. E. (ed). Evolutionary History of the “Robust” Australopithecines (Aldine de Gruyter, New York, 1988).

  57. 57.

    Strait, D. S. et al. Viewpoints: diet and dietary adaptations in early hominins: the hard food perspective. Am. J. Phys. Anthropol. 151, 339–355 (2013).

  58. 58.

    Smith, A. L. et al. The feeding biomechanics and dietary ecology of Paranthropus boisei. Anat. Rec. (Hoboken) 298, 145–167 (2015).

  59. 59.

    Rabenold, D. & Pearson, O. M. Abrasive, silica phytoliths and the evolution of thick molar enamel in primates, with implications for the diet of Paranthropus boisei. PLoS ONE 6, e28379 (2011).

  60. 60.

    Scott, J. E., McAbee, K. R., Eastman, M. M. & Ravosa, M. J. Experimental perspective on fallback foods and dietary adaptations in early hominins. Biol. Lett. 10, 20130789 (2014).

  61. 61.

    Ungar, P. S., Grine, F. E. & Teaford, M. F. Dental microwear and diet of the Plio-Pleistocene hominin Paranthropus boisei. PLoS ONE 3, e2044 (2008).

  62. 62.

    Cerling, T. E. et al. Diet of Paranthropus boisei in the early Pleistocene of East Africa. Proc. Natl Acad. Sci. USA 108, 9337–9341 (2011).

  63. 63.

    King, R. A. Using Ailuropoda melanoleuca as a Model Species for Studying the Ecomorphology of Paranthropus. MSc. thesis, Marshall Univ. (2014).

  64. 64.

    Weng, Z. Y. et al. Giant panda’s tooth enamel: structure, mechanical behavior and toughening mechanisms under indentation. J. Mech. Behav. Biomed. Mater. 64, 125–138 (2016).

  65. 65.

    Ungar, P. S. & Hlusko, L. J. The evolutionary path of least resistance. Science 353, 29–30 (2016).

  66. 66.

    Lucas, P. W. Dental Functional Morphology: How Teeth Work (Cambridge Univ. Press, Cambridge, 2004).

  67. 67.

    Souron, A. in Ecology, Conservation and Management of Wild Pigs and Peccaries (eds Melletti, M. & Meijaard, E.) 29–38 (Cambridge Univ. Press, Cambridge, 2017).

  68. 68.

    Ledogar, J. A. et al. Mechanical evidence that Australopithecus sediba was limited in its ability to eat hard foods. Nat. Commun. 7, 10596 (2016).

  69. 69.

    Daegling, D. J., Carlson, K. J., Tafforeau, P., de Ruiter, D. J. & Berger, L. R. Comparative biomechanics of Australopithecus sediba mandibles. J. Hum. Evol. 100, 73–86 (2016).

  70. 70.

    Grine, F. E. & Susman, R. L. Radius of Paranthropus robustus from member 1, Swartkrans formation, South Africa. Am. J. Phys. Anthropol. 84, 229–248 (1991).

  71. 71.

    Patel, B. A. The hominoid proximal radius: re-interpreting locomotor behaviors in early hominins. J. Hum. Evol. 48, 415–432 (2005).

  72. 72.

    Susman, R. L. Hand of Paranthropus robustus from Member 1, Swartkrans: fossil evidence for tool behavior. Science 240, 781–784 (1988).

  73. 73.

    Backwell, L. R. & d’Errico, F. Additional evidence on the early hominid bone tools from Swartkrans with reference to spatial distribution of lithic and organic artefacts. S. Afr. J. Sci. 99, 259–267 (2003).

  74. 74.

    Backwell, L. R. & d’Errico, F. Early hominid bone tools from Drimolen, South Africa. J. Archaeol. Sci. 35, 2880–2894 (2008).

  75. 75.

    d’Errico, F. & Backwell, L. R. Assessing the function of early hominin bone tools. J. Archaeol. Sci. 36, 1764–1773 (2009).

  76. 76.

    Churchill, S. E. et al. The upper limb of Australopithecus sediba. Science 340, 1233477 (2013).

  77. 77.

    Rein, T. R., Harrison, T., Carlson, K. J. & Harvati, K. Adaptation to suspensory locomotion in Australopithecus sediba. J. Hum. Evol. 104, 1–12 (2017).

  78. 78.

    Macho, G. in Trends in Biological Anthropology Vol. 1 (eds Gerdau-Radonić, K. & McSweeney, K.) 1–10 (Oxbow, Oxford, 2015).

  79. 79.

    Tseng, Z. J. Connecting Hunter–Schreger Band microstructure to enamel microwear features: new insights from durophagous carnivores. Acta Palaeontol. Pol. 57, 473–484 (2012).

  80. 80.

    Alloing-Séguier, L. et al. Enamel microstructure evolution in anthracotheres (Mammalia, Cetartiodactyla) and new insights on hippopotamoid phylogeny. Zool. J. Linn. Soc. 171, 668–695 (2014).

  81. 81.

    Constantino, P. J., Borrero-Lopez, O., Pajares, A. & Lawn, B. R. Simulation of enamel wear for reconstruction of diet and feeding behavior in fossil animals: a micromechanics approach. BioEssays 38, 89–99 (2016).

  82. 82.

    Towle, I., Irish, J. D. & De Groote, I. Behavioral inferences from the high levels of dental chipping in Homo naledi. Am. J. Phys. Anthropol. 164, 184–192 (2017).

  83. 83.

    Sponheimer, M. et al. Isotopic evidence for dietary variability in the early hominin Paranthropus robustus. Science 314, 980–982 (2006).

  84. 84.

    Sponheimer, M. et al. Hominins, sedges, and termites: new carbon isotope data from the Sterkfontein valley and Kruger National Park. J. Hum. Evol. 48, 301–312 (2005).

  85. 85.

    Sponheimer, M. & Lee-Thorp, J. A. Differential resource utilization by extant great apes and australopithecines: towards solving the C4 conundrum. Comp. Biochem. Physiol. A 136, 27–34 (2003).

  86. 86.

    Sponheimer, M. in The Paleobiology of Australopithecus (eds Reed, K. E., Fleagle, J. G. & Leakey, R. E.) 225–233 (Springer, Dordrecht, 2013).

  87. 87.

    Dominy, N. J., Vogel, E. R., Yeakel, J. D., Constantino, P. & Lucas, P. W. Mechanical properties of plant underground storage organs and implications for dietary models of early hominins. Evol. Biol. 35, 159–175 (2008).

  88. 88.

    Yeakel, J. D., Dominy, N. J., Koch, P. L. & Mangel, M. Functional morphology, stable isotopes, and human evolution: a model of consilience. Evolution 68, 190–203 (2014).

  89. 89.

    Sponheimer, M. & Lee-Thorp, J. A. Oxygen isotopes in enamel carbonate and their ecological significance. J. Archaeol. Sci. 26, 723–728 (1999).

  90. 90.

    Levin, N. E., Cerling, T. E., Passey, B. H., Harris, J. M. & Ehleringer, J. R. A stable isotope aridity index for terrestrial environments. Proc. Natl Acad. Sci. USA 103, 11201–11205 (2006).

  91. 91.

    Faith, J. T. Paleodietary change and its implications for aridity indices derived from δ18O of herbivore tooth enamel. Palaeogeogr. Palaeoclimatol. Palaeoecol. 490, 571–578 (2018).

  92. 92.

    Lee-Thorp, J. A., Sponheimer, M., Passey, B. H., de Ruiter, D. J. & Cerling, T. E. Stable isotopes in fossil hominin tooth enamel suggest a fundamental dietary shift in the Pliocene. Philos. Trans. R. Soc. Lond. B 365, 3389–3396 (2010).

  93. 93.

    Souron, A., Balasse, M. & Boisserie, J.-R. Intra-tooth isotopic profiles of canines from extant Hippopotamus amphibius and late Pliocene hippopotamids (Shungura Formation, Ethiopia): insights into the seasonality of diet and climate. Palaeogeogr. Palaeoclimatol. Palaeoecol. 342–343, 97–110 (2012).

  94. 94.

    Sponheimer, M., de Ruiter, D., Lee-Thorp, J. & Späth, A. Sr/Ca and early hominin diets revisited: new data from modern and fossil tooth enamel. J. Hum. Evol. 48, 147–156 (2005).

  95. 95.

    Ungar, P. S. & Sponheimer, M. The diets of early hominins. Science 334, 190–193 (2011).

  96. 96.

    Grine, F. E., Sponheimer, M., Ungar, P. S., Lee-Thorp, J. & Teaford, M. F. Dental microwear and stable isotopes inform the paleoecology of extinct hominins. Am. J. Phys. Anthropol. 148, 285–317 (2012).

  97. 97.

    Ungar, P. S., Scott, J. R. & Steininger, C. M. Dental microwear differences between eastern and southern African fossil bovids and hominins. S. Afr. J. Sci. 112, 2015-0393 (2016).

  98. 98.

    Peterson, A. S., Abella, E. F., Grine, F. E., Teaford, M. F. & Ungar, P. S. Microwear textures of Australopithecus africanus and Paranthropus robustus molars in relation to environment and diet. J. Hum. Evol. 119, 42–63 (2018).

  99. 99.

    Lee-Thorp, J. A., van der Merwe, N. J. & Brain, C. K. Diet of Australopithecus robustus at Swartkrans from stable carbon isotopic analysis. J. Hum. Evol. 27, 361–372 (1994).

  100. 100.

    Lee-Thorp, J., Thackeray, J. F. & van der Merwe, N. The hunters and the hunted revisited. J. Hum. Evol. 39, 565–576 (2000).

  101. 101.

    Steininger, C. M. The Dietary Behaviour of Early Pleistocene Bovids from Cooper’s Cave and Swartkrans, South Africa. PhD thesis, Univ. of the Witwatersrand (2011).

  102. 102.

    Adams, J. W. Stable carbon isotope analysis of fauna from the Gondolin GD 2 fossil assemblage, South Africa. Ann. Ditsong Natl. Mus. Nat. Hist. 2, 1–5 (2012).

  103. 103.

    Reed, K. E. Early hominid evolution and ecological change through the African Plio-Pleistocene. J. Hum. Evol. 32, 289–322 (1997).

  104. 104.

    de Ruiter, D. J., Sponheimer, M. & Lee-Thorp, J. A. Indications of habitat association of Australopithecus robustus in the Bloubank Valley, South Africa. J. Hum. Evol. 55, 1015–1030 (2008).

  105. 106.

    Kuman, K. & Clarke, R. J. Stratigraphy, artefact industries and hominid associations for Sterkfontein, member 5. J. Hum. Evol. 38, 827–847 (2000).

  106. 107.

    Fashing, P. J., Nguyen, N., Venkataraman, V. V. & Kerby, J. T. Gelada feeding ecology in an intact ecosystem at Guassa, Ethiopia: variability over time and implications for theropith and hominin dietary evolution. Am. J. Phys. Anthropol. 155, 1–16 (2014).

  107. 108.

    d’Huart, J.-P. in Pigs, Peccaries, and Hippos: Status Survey and Conservation Action Plan (ed. Oliver, W. L. R.) 84–92 (IUCN, Gland, 1993).

  108. 109.

    Quinn, R. L. et al. Pedogenic carbonate stable isotopic evidence for wooded habitat preference of early Pleistocene tool makers in the Turkana Basin. J. Hum. Evol. 65, 65–78 (2013).

  109. 110.

    Robinson, J. R., Rowan, J., Campisano, C. J., Wynn, J. G. & Reed, K. E. Late Pliocene environmental change during the transition from Australopithecus to Homo. Nat. Ecol. Evol. 1, 0159 (2017).

  110. 111.

    Signor, P. W. III & Lipps, J. H. in Geological Implications of Impacts of Large Asteroids and Comets on the Earth (eds Silver, L. T. & Schultz, P. H.) 291–296 (The Geological Society of America, Boulder, 1982).

  111. 112.

    White, T. D. in Paleoclimate and Evolution, with Emphasis on Human Origins (eds Vrba, E. S. et al.) 369–384 (Yale Univ. Press, New Haven, 1995).

  112. 113.

    Codron, D., Brink, J. S., Rossouw, L. & Clauss, M. The evolution of ecological specialization in southern African ungulates: competition- or physical environmental turnover? Oikos 117, 344–353 (2008).

  113. 114.

    Wood, B. & Strait, D. Patterns of resource use in early Homo and Paranthropus. J. Hum. Evol. 46, 119–162 (2004).

  114. 115.

    Moggi-Cecchi, J., Menter, C., Boccone, S. & Keyser, A. Early hominin dental remains from the Plio-Pleistocene site of Drimolen, South Africa. J. Hum. Evol. 58, 374–405 (2010).

  115. 116.

    Klein, R. G., Avery, G., Cruz-Uribe, K. & Steele, T. E. The mammalian fauna associated with an archaic hominin skullcap and later Acheulean artifacts at Elandsfontein, Western Cape Province, South Africa. J. Hum. Evol. 52, 164–186 (2007).

  116. 117.

    Brink, J. S. et al. First hominine remains from a ~1.0 million year old bone bed at Cornelia-Uitzoek, Free State Province, South Africa. J. Hum. Evol. 63, 527–535 (2012).

  117. 118.

    Asfaw, B. et al. Remains of Homo erectus from Bouri, Middle Awash, Ethiopia. Nature 416, 317–320 (2002).

  118. 119.

    Abbate, E. et al. A one-million-year-old Homo cranium from the Danakil (Afar) Depression of Eritrea. Nature 393, 458–460 (1998).

  119. 120.

    Bahr, A. et al. Deciphering bottom current velocity and paleoclimate signals from contourite deposits in the Gulf of Cádiz during the last 140 kyr: an inorganic geochemical approach. Geochem. Geophys. Geosyst. 15, 3145–3160 (2014).

  120. 121.

    Adegbie, A. T., Schneider, R. R., Röhl, U. & Wefer, G. Glacial millennial-scale fluctuations in central African precipitation recorded in terrigenous sediment supply and freshwater signals offshore Cameroon. Palaeogeogr. Palaeoclimatol. Palaeoecol. 197, 323–333 (2003).

  121. 122.

    Dickson, A. J., Leng, M. J., Maslin, M. A. & Röhl, U. Oceanic, atmospheric and ice-sheet forcing of South East Atlantic Ocean productivity and South African monsoon intensity during MIS-12 to 10. Quat. Sci. Rev. 29, 3936–3947 (2010).

  122. 123.

    Revel, M. et al. 20,000 years of Nile River dynamics and environmental changes in the Nile catchment area as inferred from Nile upper continental slope sediments. Quat. Sci. Rev. 130, 200–221 (2015).

  123. 124.

    Ziegler, M. et al. Development of Middle Stone Age innovation linked to rapid climate change. Nat. Commun. 4, 1905 (2013).

  124. 125.

    Rohling, E. J. et al. Sea-level and deep-sea-temperature variability over the past 5.3 million years. Nature 508, 477–482 (2014).

  125. 126.

    IAEA. Isotope Hydrology Information System, The ISOHIS Database http://www.iaea.org/water (2006).

  126. 127.

    Risi, C., Bony, S. & Vimeux, F. Influence of convective processes on the isotopic composition (δ18O and δD) of precipitation and water vapor in the tropics: 2. physical interpretation of the amount effect. J. Geophys. Res. 113, D19306 (2008).

  127. 128.

    Stock, W. D., Chuba, D. K. & Verboom, G. A. Distribution of South African C3 and C4 species of Cyperaceae in relation to climate and phylogeny. Austral Ecol. 29, 313–319 (2004).

  128. 129.

    Dupont, L. M. & Kuhlmann, H. Glacial-interglacial vegetation change in the Zambezi catchment. Quat. Sci. Rev. 155, 127–135 (2017).

  129. 130.

    Schrag, D. P. et al. The oxygen isotopic composition of seawater during the Last Glacial Maximum. Quat. Sci. Rev. 21, 331–342 (2002).

  130. 131.

    Sachse, D. et al. Molecular paleohydrology: interpreting the hydrogen-isotopic composition of lipid biomarkers from photosynthesizing organisms. Annu. Rev. Earth Planet. Sci. 40, 221–249 (2012).

  131. 132.

    Collins, J. A. et al. Estimating the hydrogen isotopic composition of past precipitation using leaf-waxes from western Africa. Quat. Sci. Rev. 65, 88–101 (2013).

  132. 133.

    Schefuß, E., Schouten, S., Jansen, J. H. & Sinninghe Damsté, J. S. African vegetation controlled by tropical sea surface temperatures in the mid-Pleistocene period. Nature 422, 418–421 (2003).

  133. 134.

    Grinsted, A., Moore, J. C. & Jevrejeva, S. Application of the cross wavelet transform and wavelet coherence to geophysical time series. Nonlinear Process. Geophys. 11, 561–566 (2004).

  134. 135.

    Schulz, M. & Mudelsee, M. REDFIT: estimating red-noise spectra directly from unevenly spaced paleoclimatic time series. Comput. Geosci. 28, 421–426 (2002).

  135. 136.

    Imbrie, J. et al. in Milankovitch and Climate: Understanding the Response to Astronomical Forcing (eds Berger, A. et al.) 269–305 (Springer, Dordrecht, 1984).

  136. 137.

    Dirks, P. H. et al. Geological setting and age of Australopithecus sediba from southern Africa. Science 328, 205–208 (2010).

  137. 138.

    Pickering, R. et al. Australopithecus sediba at 1.977 Ma and implications for the origins of the genus Homo. Science 333, 1421–1423 (2011).

  138. 139.

    Berger, L. R., de Ruiter, D. J., Steininger, C. M. & Hancox, J. Preliminary results of excavations at the newly investigated Coopers D deposit, Gauteng, South Africa. S. Afr. J. Sci. 99, 276–278 (2003).

  139. 140.

    de Ruiter, D. J. et al. New Australopithecus robustus fossils and associated U-Pb dates from Cooper’s Cave (Gauteng, South Africa). J. Hum. Evol. 56, 497–513 (2009).

  140. 141.

    Keyser, A. W., Menter, C. G., Moggi-Cecchi, J., Rayne Pickering, T. & Berger, L. R. Drimolen: a new hominid-bearing site in Gauteng, South Africa. S. Afr. J. Sci. 96, 193–197 (2000).

  141. 142.

    Adams, J. W., Rovinsky, D. S., Herries, A. I. R. & Menter, C. G. Macromammalian faunas, biochronology and palaeoecology of the early Pleistocene Main Quarry hominin-bearing deposits of the Drimolen Palaeocave System, South Africa. PeerJ 4, e1941 (2016).

  142. 143.

    Thackeray, J. F., Kirschvink, J. L. & Raub, T. D. Palaeomagnetic analyses of calcified deposits from the Plio-Pleistocene hominid site of Kromdraai, South Africa: news & views. S. Afr. J. Sci. 98, 537–540 (2002).

  143. 144.

    Herries, A. I. R., Curnoe, D. & Adams, J. W. A multi-disciplinary seriation of early Homo and Paranthropus bearing palaeocaves in southern Africa. Quat. Int. 202, 14–28 (2009).

  144. 145.

    Herries, A. I. R & Adams, J. W. Clarifying the context, dating and age range of the Gondolin hominins and Paranthropus in South Africa. J. Hum. Evol. 65, 676–681 (2013).

  145. 146.

    Braga, J., Fourvel, J.-B., Lans, B., Bruxelles, L. & Thackeray, J. F. in Kromdraai. A Birthplace of Paranthropus in the Cradle of Humankind (eds Braga, J. & Thackeray, J. F.) 1–16 (SUN, Stellenbosch, 2016).

  146. 147.

    Herries, A. I., Adams, J. W., Kuykendall, K. L. & Shaw, J. Speleology and magnetobiostratigraphic chronology of the GD 2 locality of the Gondolin hominin-bearing paleocave deposits, North West Province, South Africa. J. Hum. Evol. 51, 617–631 (2006).

  147. 148.

    Adams, J. W., Herries, A. I., Kuykendall, K. L. & Conroy, G. C. Taphonomy of a South African cave: geological and hydrological influences on the GD 1 fossil assemblage at Gondolin, a Plio-Pleistocene paleocave system in the Northwest Province, South Africa. Quat. Sci. Rev. 26, 2526–2543 (2007).

  148. 149.

    Curnoe, D. K. A. Contribution to the Question of Early Homo in Southern Africa: Researches into Dating, Taxonomy and Phylogeny Reconstruction. PhD thesis, Australian National University (1999).

  149. 150.

    Herries, A. I. & Shaw, J. Palaeomagnetic analysis of the Sterkfontein palaeocave deposits: implications for the age of the hominin fossils and stone tool industries. J. Hum. Evol. 60, 523–539 (2011).

  150. 151.

    Granger, D. E. et al. New cosmogenic burial ages for Sterkfontein Member 2 Australopithecus and Member 5 Oldowan. Nature 522, 85–88 (2015).

  151. 152.

    Gibbon, R. J. et al. Cosmogenic nuclide burial dating of hominin-bearing Pleistocene cave deposits at Swartkrans, South Africa. Quat. Geochronol. 24, 10–15 (2014).

  152. 153.

    Curnoe, D., Grün, R., Taylor, L. & Thackeray, F. Direct ESR dating of a Pliocene hominin from Swartkrans. J. Hum. Evol. 40, 379–391 (2001).

  153. 154.

    Pickering, R., Kramers, J. D., Hancox, P. J., de Ruiter, D. J. & Woodhead, J. D. Contemporary flowstone development links early hominin bearing cave deposits in South Africa. Earth Planet. Sci. Lett. 306, 23–32 (2011).

  154. 155.

    Balter, V. et al. U–Pb dating of fossil enamel from the Swartkrans Pleistocene hominid site, South Africa. Earth Planet. Sci. Lett. 267, 236–246 (2008).

  155. 156.

    Vrba, E. S. Some evidence of chronology and palaeoecology of Sterkfontein, Swartkrans and Kromdraai from the fossil Bovidae. Nature 254, 301–304 (1975).

  156. 157.

    Vrba, E. S. in L’environnement des hominidés au Plio-Pléistocène (eds Beden, M. et al.) 345–369 (Masson, 1985).

  157. 158.

    Churcher, C. S. & Watson, V. in Swartkrans: A Cave’s Chronicle of Early Man (ed. Brain, C. K.) 137–150 (Transvaal Museum, Pretoria, 1993).

  158. 159.

    Blackwell, B. A. Problems associated with reworked teeth in electron spin resonance (ESR) dating. Quat. Sci. Rev. 13, 651–660 (1994).

  159. 160.

    Steininger, C. Local ecological profile for Paranthropus robustus in South Africa using stable carbon isotopes from associated bovid teeth. Quat. Int. 279–280, 466 (2012).

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Acknowledgements

T.C. is supported by CNRS-INSU. Funding from LEFE-IMAGO CNRS INSU project SeaSalt is acknowledged. T.C. was partly supported by the ‘Laboratoire d’Excellence’ LabexMER (ANR-10-LABX-19) and co-funded by a grant from the French government under the program ‘Investissements d’Avenir’, and by a grant from the Regional Council of Brittany (SAD programme). J.A.C. acknowledges funding from the ERC project ‘STEEPClim’. E.S. and L.D. acknowledge funding through the DFG Research Center/Cluster of Excellence ‘The Ocean in the Earth System’ at MARUM – Center for Environmental Sciences. A.S. acknowledges funding through the LaScArBx, a programme supported by the Agence Nationale de la Recherche (ANR-10-LABX-52). C.G.-C. was supported by CREST (grant number JPMJCR12A3; P.I. SLS) funded by the Japan Science and Technology (JST). Core MD96-2048 was collected during the MOZAPHARE cruise of the RV Marion Dufresne, supported by the French agencies Ministère de l’Education Nationale de la Recherche et de la Technologie, Centre National de la Recherche Scientifique (CNRS) and Institut Paul Emile Victor (IPEV).

Reviewer information

Nature thanks C. O’Brien, M. Petraglia, K. Uno and the other anonymous reviewer(s) for their contribution to the peer review of this work.

Author information

Affiliations

  1. EPOC, UMR 5805, CNRS, University of Bordeaux, Pessac, France

    • Thibaut Caley
    • , Thomas Extier
    • , Bruno Malaizé
    • , Linda Rossignol
    • , Frédérique Eynaud
    • , Philippe Martinez
    • , Karine Charlier
    • , Mélanie Wary
    • , Pierre-Yves Gourves
    • , Isabelle Billy
    •  & Jacques Giraudeau
  2. Laboratoire des Sciences du Climat et de l’Environnement, LSCE/IPSL, CEA-CNRS-UVSQ, Université Paris-Saclay, Gif-sur-Yvette, France

    • Thomas Extier
    •  & Didier M. Roche
  3. GFZ – German Research Center for Geosciences, Section 5.1 Geomorphology, Organic Surface Geochemistry Laboratory, Potsdam, Germany

    • James A. Collins
  4. Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany

    • James A. Collins
  5. MARUM – Center for Marine Environmental Sciences, University of Bremen, Bremen, Germany

    • Enno Schefuß
    •  & Lydie Dupont
  6. PACEA, UMR 5199, CNRS, University of Bordeaux, Pessac, France

    • Antoine Souron
  7. Department of Geography, Durham University, Durham, UK

    • Erin L. McClymont
  8. Department of Biogeochemistry (JAMSTEC), Yokosuka, Japan

    • Francisco J. Jimenez-Espejo
  9. Research and Development Center for Global Change, (JAMSTEC), Yokohama, Japan

    • Carmen García-Comas
  10. Ecology Group, University of Vic – Central University of Catalonia, Barcelona, Spain

    • Carmen García-Comas
  11. Vrije Universiteit Amsterdam, Faculty of Science, Cluster Earth and Climate, Amsterdam, The Netherlands

    • Didier M. Roche
  12. Unité Géosciences Marines, Institut Français de Recherche pour l’Exploitation de la Mer (IFREMER), Plouzané, France

    • Stephan J. Jorry

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Contributions

T.C. designed the study. T.C., T.E., M.W. and P.-Y.G. performed the Mg/Ca measurements. L.R. analysed the foraminifera assemblages, and T.C. and F.E. analysed the results and performed the transfer function. T.C., T.E., B.M. and K.C. performed the δ18O analyses on foraminifera. T.C., J.G., P.M. and I.B. performed the XRF measurements and F.J.J.-E. and C.G.-C. conducted the statistical analyses on XRF. J.A.C. and E.S. performed plant-wax δD and δ13C analyses. L.D. performed the pollen analysis. A.S. and T.C. produced the synthesis on the ecology and environments of South African hominins and conducted the comparisons to the marine record. T.C. and D.M.R. performed and analysed the iLOVECLIM model results. T.C. analysed the results and all authors participated in the interpretation. T.C. wrote the manuscript with contributions from all authors.

Competing interests

The authors declare no competing interests.

Corresponding author

Correspondence to Thibaut Caley.

Extended data figures and tables

  1. Extended Data Fig. 1 ln(Fe/Ca) as a proxy for Limpopo runoff.

    Calcium and iron both have complex and multiple origins in marine sediments. Iron can be related to redox variations, detrital and fluvial input, among others, and calcium can be related to the biogenic fraction (foraminifera or nannofossils) and detrital input. To properly interpret the ln(Fe/Ca) ratio at our study location, we applied principal components analysis120. a, PC1 describes 66% of the total variance for the entire site MD96-2048. The negative loadings for PC1 are calcium and strontium, and all other elements (aluminium, silicon, potassium, titanium, iron and zirconium) have positive loadings. Calcium and strontium are associated with biogenic carbonate and are mainly related to presence of foraminifera. Element matrix correlation shows a strong positive linear correlation (R > 0.70) between iron and typically detrital elements, such as aluminium, silicon, titanium and potassium. Calcium shows negative correlation with iron (R = −0.5). b, ln(Fe/Ca) shows a strong correlation with PC1 (R = 0.94) and a strong relationship with Limpopo runoff proxies (Extended Data Fig. 3). Iron and titanium elements are related to terrigenous and siliciclastic components (heavy minerals and oxides) and the variation in carbonate content (calcium) is mainly due to dilution by terrigenous sediment. ln(Fe/Ca) is therefore a proxy of Limpopo runoff, consistent with previous studies in riverine basins throughout the African continent10,121,122,123,124. To confirm a weak influence of sea-level changes on the Fe/Ca record, we compared our ln(Fe/Ca) record with a previous reconstruction of the deep-water δ18O component for relative sea level125, (b, bottom). Both records are plotted against the LR04 chronology. Visual inspection and statistical testing do not support a dominant effect of sea-level changes on the ln(Fe/Ca) record (R = 0.05). PC3, which describes 11% of the total variance for the entire site MD96-2048, is closely related to sea-level changes. The negative loadings for PC3 are mainly strontium and, to a lesser degree, potassium and titanium, and the main positive loadings are zirconium and, to a lesser degree, silicon.

  2. Extended Data Fig. 2 Control on the δD composition of precipitation in the Limpopo catchment.

    a, b, Seasonal δD composition of precipitation (a) and amount of precipitation at Pretoria station126 (b), in comparison to the results of the iLOVECLIM model at the corresponding latitude and longitude48,49. All data are centred on their annual average. Depleted δD values are indicative of increasing amounts of rainfall127. c, Results of the transient simulation with the isotope-enabled numerical climate model iLOVECLIM for the δD composition of precipitation and precipitation in the Limpopo catchment (about −27.5° S to −22° S and 30° E to 36° E), for the past 150 kyr (Methods)51. Black curves show the results after filtering with a low-pass filter. The δD composition of precipitation and precipitation amount in the Limpopo catchment are negatively correlated (R = −0.63, \(P\ll 0.001\)) for the past 150 kyr. Maxima of precipitation are phased with maxima in austral summer insolation at 30° S and lead to more-depleted δDprecipitation (amount effect).

  3. Extended Data Fig. 3 Relationship between Limpopo runoff, local Southern Hemisphere insolation and the C31 n-alkane δ13C record for the past 800 kyr.

    a, Comparison between the ln(Fe/Ca) XRF signal and austral summer local insolation at 30° S31. b, Comparison between the ln(Fe/Ca) XRF signal and the brGDGT concentration in the sediment15. brGDGTs are commonly found in soil and can be attributed to Limpopo River runoff15. c, Comparison between the ln(Fe/Ca) XRF signal and the C31 n-alkane δ13C record16. An increased amount of Limpopo River discharge is associated with more C4 plant input and an increase in austral summer insolation at 30° S. d, Comparison between inverted ln(Fe/Ca) XRF signal and the accumulation rate (AR) of CaCO3 as a measure of biogenic carbonate. The ln(Fe/Ca) XRF record is not primarily controlled by dilution due to biological productivity (R = 0.1). A previous study of the past 0.8 Myr of core MD96-2048 interpreted shifts towards more-depleted δ13Cwax as potentially reflecting more-humid conditions16. However, the anti-correlation between δ13Cwax and δDwax values (Extended Data Fig. 4) in our study indicates that enriched δ13Cwax values are associated with more-humid conditions. Because C4 plants in the Limpopo catchment are dominant in the interior (Fig. 1), we propose that more-enriched δ13Cwax values indicate a higher relative contribution from sources located farther upstream (more C4 plants) during times of high runoff, compared to only downstream sources (more C3 plants) during times of low discharge. In addition, humid conditions would have favoured the extension of sedge-rich vegetation (Cyperaceae, of which 20–60% are C4 plants in this region128) in riverine swamps and floodplains along the river course, explaining the detected increase in Cyperaceae pollen at times of increased fluvial discharge (Fig. 2). Studies of sediments from the adjacent Zambezi catchment similarly suggest the extension of swampy sedge-rich vegetation—including C4-Cyperaceae—when river discharge was high, and infer that more C4 plant waxes are exported to the ocean when the flooding of floodplains occurs during rainfall maxima10,129.

  4. Extended Data Fig. 4 Relation between the δ13C C31 n-alkanes record and the δD C31 n-alkanes record.

    a, Correlation between the record of δ13C C31 n-alkanes and the record of δD C31 n-alkanes, with or without vegetation and ice-volume correction (vc-ivf) over the past 2.14 Myr (n = 19 samples). An anti-correlation exists between the δ13C and the δD signals of the C31 n-alkanes. The C31 n-alkane is used because it is the most abundant homologue in the samples. b, Raw δ13Cwax, δDwax data and δDwax adjusted for ice-volume and vegetation changes from core MD96-2048. Mean analytical uncertainties are indicated. Top, δ13Cwax of the C31 homologue (data from a previous study16 in light green, and data from this study in dark green). Middle, δDwax of the C31 homologue. Bottom, δDwax of the C31 homologue adjusted for ice-volume changes (ivf) using a seawater δ18O curve125 and converting to δD assuming an increase of 7.2‰ at the Last Glacial Maximum. We use 7.2‰ because measurements of sediment pore water δ18O and δD suggest that the glacial ocean δD increase has a mean value of 7.2‰130. We also adjusted the δDwax record for vegetation changes (vc) using published fractionation factors (−123‰ ± 31‰ for C3 trees, −139‰ ± 27‰ for C4 grasses131) and the δ13Cwax signal following a previously published procedure132. End-member δ13Cwax values used for C3 and C4 vegetation were −36‰ and −21.5‰, respectively133. The error ranges for the vegetation fractionation factors are very large131. They derive from the compilation of a global dataset from individual plants, which is not comparable to an ecosystem fractionation in a specific catchment (such in the Limpopo) that will fractionate with a much smaller uncertainty. However, as we do not know the exact fractionation factor in the Limpopo catchment and regard the uncertainties from the global compilation as unrealistic for a specific ecosystem we refrained from propagating this uncertainty into the vegetation corrections. The vegetation and ice-volume-adjusted δDwax record is very similar to the unadjusted record, highlighting the fact that the adjustments have a minor effect.

  5. Extended Data Fig. 5 Statistical analyses for the ln(Fe/Ca) XRF record and PC1 SST record.

    a, Spectral power for ln(Fe/Ca) by wavelet analysis realized with a previously published MatLab package134. The thick contour designates the 5% significance level against red noise. Dashed black lines indicate the variability at the precession, obliquity and eccentricity periods. b, Spectral analysis of ln(Fe/Ca) with REDFIT135. The red line shows the false-alarm level at the 95% confidence interval. Spectral peaks exceeding the false-alarm level can be considered significant135. c, Blackman–Tukey cross correlation between ln(Fe/Ca) XRF and eccentricity–tilt–precession (ETP) realized with the Analyseries software37 for the past 2.14 Myr. ETP is constructed by normalizing and stacking eccentricity, tilt (obliquity) and negative precession to evaluate coherence and phase (timing) relative to orbital extremes136. The red curve shows the spectral power for ln(Fe/Ca) record. The black curve shows the spectral power for ETP. The coherency, which varies between 0 and 1, is represented by the grey curve and gives the interval within which the spectrum is significant. In our case, the non-zero coherency is higher than 0.55 and is significant at the 95% confidence interval (grey line). There are significant spectral peaks for eccentricity and precession but not for obliquity. The ln(Fe/Ca) XRF record and ETP are in phase at the 400-kyr period, the eccentricity leads by 16 kyr the ln(Fe/Ca) record at the 100-kyr period and the ln(Fe/Ca) record is in anti-phase with negative precession (in-phase with positive precession) at the 19- and 23-kyr periods. The three statistical analyses are consistent and indicate significant variability at the 400-, 100-, 23- and 19-kyr periods and insignificant variability at the 41-kyr period. d, Comparison between the precessional component of the ln(Fe/Ca) record (Gaussian filter frequency 1/23,000; bandwidth: 5 ×10−6) obtained with the Analyseries software37 and the precession index. Maxima of the ln(Fe/Ca) precession component are in phase with precession index maxima. The precession cycles in the ln(Fe/Ca) record appear particularly strong between about 0.9 and 0.6 Ma. eg, The same statistical analyses as in ac, respectively, but for the PC1 SST record. In e, dashed white lines indicate the variability at the precession, obliquity and eccentricity periods. The three statistical analyses indicate significant variability at the 100- and 41-kyr periods but not significant power for the 400-kyr and 23-kyr (precession) periods.

  6. Extended Data Fig. 6 Reconstruction using SST proxies for core MD96-2048 for the past 2.14 Myr.

    a, Reconstruction of SST using two different methods: Mg/Ca reconstruction based on previous15 and new data (Mg/Ca ratios were converted into temperature values by applying a previously established equation40) and foraminifera transfer function reconstruction using the modern analogue technique. Error bars represent the error on the calibrations40 (Extended Data Fig. 7). b, Empirical orthogonal function analysis47 of the two SST records for the past 2.14 Myr. PC1 contains 74% of the total variance for the past 2.14 Myr. Correlation between SST proxies and PC1 for the past 2.14 Myr is R = 0.71.

  7. Extended Data Fig. 7 Foraminifera transfer function used for core MD96-2048.

    a, Location of the modern database, composed of 367 core tops from the south Indian Ocean45 with present-day SST from the World Ocean Atlas (WOA) 200929. b, Test for the modern database45 yielding to a precision of 0.8 °C for the annual SST reconstructions. Modern hydrological parameters were obtained from the WOA (1998) database using a previously developed tool (http://www.geo.uni-bremen.de/geomod/Sonst/Staff/csn/woasample.html).

  8. Extended Data Table 1 Fossil finds, their location and associated ages
  9. Extended Data Table 2 δ13C enamel of hominin and contemporaneous herbivores and associated statistical parameters for different sites in the Limpopo catchment

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