8 Oct 2021

Researchers link 700-year-old soot found in Antarctica to fires set by early Māori

1:29 pm on 8 October 2021

An overseas research team has linked soot preserved in Antarctic ice to fires set in Aotearoa by Māori settlers 700 years ago.

Antarctica, Southern Ocean, Antarctic Peninsula, Graham Land, Antarctic Circle Icebergs (66°33'S 66°33'W) (Photo by BRUSINI Aurélien / hemis.fr / hemis.fr / Hemis via AFP)

Antarctica (file image). Photo: AFP

The researchers say the finding is a dramatic example of early humanities' environmental impact, but there has been some criticism here in New Zealand about the research.

Reno, Nevada Desert Research Institute environmental scientist Joseph McConnell told Morning Report over the last few years he and his colleagues had collected ice cores from Antarctica - some from the Antarctic continent and some from the Antarctic peninsula.

"We measured black carbon or soot in those ice cores - there are six altogether and our objective was to study atmospheric chemistry over the past 2000 years," McConnell said.

"So two of the ice cores are from the northern tip of the Antarctic Peninsula and the other four are from continental Antarctica, maybe 2000 kilometres south of where the ones from the northern tip of the Antarctic are from and we can tell from that array (of cores) - because of atmospheric circulation and using climate models and so forth - that these emissions had to come from poleward or south of 40 degrees south latitude, and that leaves three possibilities.

"Tasmania, New Zealand or Patagonia. And if we look at local records of burning of forest fires in the past from lake sediment, charcoal records and things like that, burning was pronounced early here during this 2000-year period in Tasmania and Patagonia, as a result of climate variations, but then in New Zealand you don't really have much of a natural fire cycle.

"[The year 1300] is when the Māori arrived and settled New Zealand and started using fire for land clearing and things like that."

McConnell they were working to understand how black carbon particles in the atmosphere changed the climate of the earth through radiative forcing.

At least one Māori academic has pushed back against the research.

In comments published by the Science Media Centre, University of Waikato acting dean of the Faculty of Māori and Indigenous Studies associate professor Sandy Morrison said the study was "devoid of context, devoid of cultural understandings and is yet another example of what we have grown to expect from western science".

"It relies on measurements, modelling and silo thinking and the paper whether intentional or not, posits Māori as the 'naughty' offenders.

"Moreover, it reeks of scientific arrogance with its implicit assumption that somehow Māori have a lot to account for in terms of contributing to carbon emissions and destroying the pristine environment of the Southern Oceans and Antarctica.

"Goodness knows why Māori are primarily emphasised, and for what purpose this article was written."

McConnell told Morning Report "I emphasise I'm a scientist and it's a scientific study and I think if you read the paper carefully, you'll see that there is no - I don't think we said anything culturally insensitive.

"It's really about atmospheric chemistry and atmospheric transport, and not so much about the Māori … Science is about observation, repeatability, peer reviewed literature or things like that, that demonstrate as close to fact as we can come and … I'm sorry if our conclusions were read way that we didn't intend them, I should say.

"You know, again, this is based on observation and evidence in Antarctica, not any sort of criticism of land stewardship, or anything else by the Māori."

Victoria University of Wellington's Dr Holly Winton said via the Science Media Centre that "black carbon is important for our climate because it absorbs sunlight warming the planet.

"Due to the very small size of black carbon particles, a few nanometres in diameter, winds can transport black carbon thousands of kilometres from the location of the fire. Black carbon from Southern Hemisphere fires reaches as far as the pristine Antarctic continent. The record of black carbon in Antarctica ice cores provides a history of past fire activity."

Winton said ice core records drilled by the New Zealand ice core program in the Ross Sea region - located directly downwind from New Zealand - would provide additional information about black carbon and help answer some of the questions raised by the study.

"Further geochemical evidence may pinpoint the source of the black carbon by linking the organic chemistry signal in the ice core to specific types of vegetation."

Te Pūnaha Matatini Centre of Research Excellence in Complex Systems director Dr Priscilla Wehi said the research was "scientifically spectacular" but that the work led her to "reflect on diversity and inclusion in science".

"The authors, based across northern America, Europe and Australia, also apparently lack New Zealand collaboration despite the central topic of Māori burning and fire use. 'Helicopter science', where research is led and conducted by those who live and work far from the subject of their work, is currently under scrutiny in the research community.

"An important critique is that this approach is likely to miss important insights. The ethics of such 'helicopter science' have been debated widely over the last year or so, as concerns over the exclusion of different groups from research, including Indigenous peoples, have escalated. Indeed, this issue has been noted by the very journal in which this study is published.

"Issues that have already been researched locally - from dust transport to Antarctica through to population estimates of Māori settlement - are often identified by local collaborators who, one hopes, have additionally been building the next generation of researchers in the nation where the focus of the research is situated. All of this leads me to return to this paper, which I found fascinating, and ask - how much better could this have been, were it more inclusive in its approach?"