“Anything that’s emitted at 40°–60° south is going to get caught up in that westerly belt and make a big doughnut around Antarctica,” said McConnell. The inset map shows the locations the cores were taken from and their distance from New Zealand.
The only possible candidates were Patagonia, Tasmania, and New Zealand.Ĭhart showing the soot deposition record obtained from the James Ross Island ice core in black and those from the Antarctic mainland ice cores in red. There, black carbon levels almost tripled over the ensuing centuries, whereas the ice cores from continental Antarctica stayed relatively stable.Ītmospheric modeling (using the powerful flexible particle dispersion model) showed that for the soot particles to have landed only on the Antarctic Peninsula-which sticks up like a thumb into the prevailing westerly flow-they had to have come from a landmass located south of 40° latitude. But around 700 years ago-1297, plus or minus 30 years, to be precise-the core taken from the peninsular island sharply diverged from the rest. (Black carbon aerosols absorb light and contribute to atmospheric warming.)īut when McConnell and his colleagues compared the ice core from James Ross Island to five others from different parts of the Antarctic mainland, they found something unexpected.įor the first 1,300 years, the ice cores all told the same story. The research was part of an effort to improve climate models. They planned to map natural variations in soot deposition in the ice over the past 2,000 years using a sophisticated analysis technique developed in the DRI lab. Lead author Joe McConnell from the Desert Research Institute (DRI) in Reno, Nev., said the research team didn’t set out to look for anthropogenic impacts in Antarctica. Sophisticated modeling using the flexible particle dispersion model shows how smoke from New Zealand fires would have encircled Antarctica on the prevailing westerly winds, reaching the site on the Antarctic Peninsula but not the sites on mainland Antarctica (indicated with crosses.).
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