New Zealand was among the last habitable places on earth to be colonized by humans1. Charcoal records indicate that wildfires were rare prior to colonization and widespread following the 13th- to 14th-century Māori settlement2, but the precise timing and magnitude of associated biomass-burning emissions are unknown1,3, as are effects on light-absorbing black carbon aerosol concentrations over the pristine Southern Ocean and Antarctica4. Here we used an array of well-dated Antarctic ice-core records to show that while black carbon deposition rates were stable over continental Antarctica during the past two millennia, they were approximately threefold higher over the northern Antarctic Peninsula during the past 700 years. Aerosol modelling5 demonstrates that the observed deposition could result only from increased emissions poleward of 40° S—implicating fires in Tasmania, New Zealand and Patagonia—but only New Zealand palaeofire records indicate coincident increases. Rapid deposition increases started in 1297 (±30 s.d.) in the northern Antarctic Peninsula, consistent with the late 13th-century Māori settlement and New Zealand black carbon emissions of 36 (±21 2 s.d.) Gg y−1 during peak deposition in the 16th century. While charcoal and pollen records suggest earlier, climate-modulated burning in Tasmania and southern Patagonia6,7, deposition in Antarctica shows that black carbon emissions from burning in New Zealand dwarfed other preindustrial emissions in these regions during the past 2,000 years, providing clear evidence of large-scale environmental effects associated with early human activities across the remote Southern Hemisphere.
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Data that support the findings of this study are available from the US Antarctic Program Data Center (https://doi.org/10.15784/601464).
The FLEXPART model used in this study is available at https://www.flexpart.eu/.
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National Science Foundation (NSF) grants 0538416, 0968391, 1702830, 1832486 and 1925417 to J.R.M. funded this research, with internal funding provided by DRI for laboratory analyses of B53, B54 and the two JRI cores. Additional funding from NSF 1702814 supported P.L. and Swiss National Science Foundation grant P400P2_199285 supported S.O.B. We thank all the British, French, Argentine, German, Norwegian, Australian and American field teams for their efforts, as well as students and staff in the DRI ice-core group for assistance in the laboratory.
The authors declare no competing interests.
Peer review information Nature thanks Patrick Kirch and the other, anonymous, reviewer(s) for their contribution to the peer review of this work. Peer reviewer reports are available.
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Extended data figures and tables
a, b, JRI records used to represent the nAP. rBC measurements of the JRI_D98 record (red) from 2007 confirm 2016 measurements in the JRI_2008 core (black) (Methods). c–g, The B40 and scaled NUS08_7 records were averaged to create a DML regional composite. h–l, The B53 and scaled NUS07_7 cores were combined to create an iEAP regional composite. Shown are annual (light) and 11-year geometric mean filtered (heavy) fluxes.
a, nAP. b, iEAP. c, nAP/iEAP. d, nAP-iEAPscaled, where the iEAP scaler of 10.1 is the average nAP/iEAP ratio in the ice cores from 900 to 1200. Insets show values for New Zealand and crosses mark ice-core locations. The maps were made using Python.
Comparisons of original 2013 and selected replicate 2016 rBC measurements in the B40 ice core. a, b, Parallel B40 samples either from shallower firn (a) and deeper ice (b) were measured at the start of each day to monitor any changes in calibrations or instrument responses during the 2016 analysis of the JRI_2008 core.
Corresponding years are shown along the top. Previous high-resolution measurements extended only to 130 m so annual layer counted ended at ~180730. Here we extended annual layer counting to ~300 m or ~1,000 using new high-resolution elemental and chemical measurements over the full 363.9-m depth.
Extended Data Fig. 5 Evaluation of ice-core chronology consistency using sulfur fallout from explosive volcanism.
a–e, Annually averaged sulfur concentrations during the 12th through 18th century in the five longer ice cores in the Antarctic rBC array. The average of the four continental cores (b–e) is shown in light grey for perspective. Also shown are tie points for this time range used to constrain annual layer counting and ice flow modelling in the JRI_2008 record.
a, The chronology (black solid) is consistent with the WD2014 age scale and based on annual layer counting (red dashed) from the surface to ~275 m (2008 to 1257 CE) and ice flow modelling from ~275 m to the bottom. Flow modelling is constrained by 12 depth-age control points (diamonds) including the 3568 yBP Vostok tephra at 345.43 m also found in East Antarctic cores. Control points below 350-m depth are 358.627 m, 11988 yBP; 358.785 m, 12800 yBP; and 359.000 m, 14607 yBP). b, Water flux.
Tephra shards extracted from 345.43 m in the JRI_2008 core are geochemically matched to the Vostok tephra previously reported in a number of cores from Vostok42,50,51, South Pole51 and Dome Concordia43. Geochemical fields are based on Narcisi and colleagues 42. We determined an eruption date of 3568 yBP on the WD2014 age scale by synchronizing high-resolution sulfate measurements to continuous sulfate measurements in WAIS Divide.
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McConnell, J.R., Chellman, N.J., Mulvaney, R. et al. Hemispheric black carbon increase after the 13th-century Māori arrival in New Zealand. Nature 598, 82–85 (2021). https://doi.org/10.1038/s41586-021-03858-9