Hemispheric black carbon increase after the 13th-century Maori arrival in New Zealand

New Zealand was amongthe last habitable places on earth to be colonized by humans'. Charcoal records indicate that wildfires were rare priorto colonization and widespread followingthe 13th- to 14th-century Maori settlement(2), but the precise timing and magnitude of associated biomass-burning emissions are unknown(1,3), as are effects on light-absorbing black carbon aerosol concentrations over the pristine Southern Ocean and Antarctica(4). 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 modelling(5) demonstratesthat the observed deposition could result only from increased emissions poleward of 40 degrees 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 Maori settlement and NewZealand black carbon emissions of 36 (+/- 212 s.d.) Gg y(-1) duringpeak deposition in the 16th century. While charcoal and pollen records suggest earlier, climate-modulated burning in Tasmania and southern Patagonia(6,7), 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.

Automated summary

Research shows that black carbon emissions from New Zealand over the past two thousand years far exceeded those from fires in Tasmania and southern Patagonia, providing clear evidence of large-scale environmental effects associated with early human activities across the remote Southern Hemisphere.