20.5 A Near-Extinction Event in the Early History of New Zealand
355
people of Orokoroko, remembered the technological disparity between the two societies that arose from the long isolation of the people in New Zealand and possibly
from their experience, a thousand years before, of a near-extinction event comparable to that Flannery suggests for the Tasmanian Aborigines 3,500 years ago. If
such an event took place in about 1018 BC, as genealogical evidence from the
Tamakiwaki Moriori genealogies suggests, it would have occurred when, or just
before, extreme global cold conditions were sealing New Zealand into a long period
of cultural, genetic, technological and linguistic isolation, with all the attendant risks
for a small society that Flannery has described.
Seeking for a possible cause for a near-extinction event occurring in New Zealand
in about 1018 BC, we found that geologists Goff, Rouse, Jones et al. have estimated
that a significant eruption of Taupo took place close to this time. This early eruption
has a calibrated dating of 2,765–3,150 BP (or 1200–815 BC) [5]. The genealogical
estimate of 1018 BC for this extinction event is in the mid-range of the geological
estimate.
This eruption is represented in the Lake Huguang Maar data as the most intense
event in 4,500 years. This suggests that it may have been extreme enough to provoke
a “nuclear winter”, leading to an extreme and possibly prolonged southward shift
of the intertropical convergence zone. This could have caused a long-lasting major
drought in the Pacific and on its continental rim. It may have caused a temporary
global cold period. It is even conceivable that it may have triggered, or been one of
the factors triggering, the 600-year global cold period that began at about this time
and halted long-distance voyaging till about 400 BC. For there is no significant climate spike in the Huguang Maar data for 550 years following this event. Yancheva
et al. date the event to 1027 BC. This provides a clear correlation with accepted
dating for the beginning of the global cold period and suggests a chronological correction of only nine years for the near-extinction event in New Zealand recorded in
the two Moriori genealogies and associated traditions.
It has been suggested that the well-known later Taupo eruption of AD 186 was
associated with tsunamis, despite it being an inland event. Perhaps it triggered
undersea eruptions along the long Kermadec chain of undersea volcanoes that lies
off the east coast of New Zealand. If the earlier Taupo eruption of 1027 BC triggered a nationwide tsunami, coastal settlements may well have been destroyed with
significant loss of life.
Very small populations are genetically and physically vulnerable to even local
catastrophes. That a nationwide tsunami, perhaps only 330 years after first settlement, may have led to a near extinction of an early population is not surprising.
Based on a power law estimate for a growth rate of 0.307% per annum, a first settlement date of 1358 BC and a founder population of 289, the population of New
Zealand would have been only about 797 in 1027 BC. Were this population to have
been halved through a near-extinction event, it would have fallen below the level
needed for survival and may have remained below that level for some time. With
a population of only about 797 before the eruption, it is unlikely that any group
would have migrated to the North Island by this date – a circumstance that may have
protected the first colony from extinction. In the South Island associated tsunamis
and earthquakes may still have been perilous.
355
people of Orokoroko, remembered the technological disparity between the two societies that arose from the long isolation of the people in New Zealand and possibly
from their experience, a thousand years before, of a near-extinction event comparable to that Flannery suggests for the Tasmanian Aborigines 3,500 years ago. If
such an event took place in about 1018 BC, as genealogical evidence from the
Tamakiwaki Moriori genealogies suggests, it would have occurred when, or just
before, extreme global cold conditions were sealing New Zealand into a long period
of cultural, genetic, technological and linguistic isolation, with all the attendant risks
for a small society that Flannery has described.
Seeking for a possible cause for a near-extinction event occurring in New Zealand
in about 1018 BC, we found that geologists Goff, Rouse, Jones et al. have estimated
that a significant eruption of Taupo took place close to this time. This early eruption
has a calibrated dating of 2,765–3,150 BP (or 1200–815 BC) [5]. The genealogical
estimate of 1018 BC for this extinction event is in the mid-range of the geological
estimate.
This eruption is represented in the Lake Huguang Maar data as the most intense
event in 4,500 years. This suggests that it may have been extreme enough to provoke
a “nuclear winter”, leading to an extreme and possibly prolonged southward shift
of the intertropical convergence zone. This could have caused a long-lasting major
drought in the Pacific and on its continental rim. It may have caused a temporary
global cold period. It is even conceivable that it may have triggered, or been one of
the factors triggering, the 600-year global cold period that began at about this time
and halted long-distance voyaging till about 400 BC. For there is no significant climate spike in the Huguang Maar data for 550 years following this event. Yancheva
et al. date the event to 1027 BC. This provides a clear correlation with accepted
dating for the beginning of the global cold period and suggests a chronological correction of only nine years for the near-extinction event in New Zealand recorded in
the two Moriori genealogies and associated traditions.
It has been suggested that the well-known later Taupo eruption of AD 186 was
associated with tsunamis, despite it being an inland event. Perhaps it triggered
undersea eruptions along the long Kermadec chain of undersea volcanoes that lies
off the east coast of New Zealand. If the earlier Taupo eruption of 1027 BC triggered a nationwide tsunami, coastal settlements may well have been destroyed with
significant loss of life.
Very small populations are genetically and physically vulnerable to even local
catastrophes. That a nationwide tsunami, perhaps only 330 years after first settlement, may have led to a near extinction of an early population is not surprising.
Based on a power law estimate for a growth rate of 0.307% per annum, a first settlement date of 1358 BC and a founder population of 289, the population of New
Zealand would have been only about 797 in 1027 BC. Were this population to have
been halved through a near-extinction event, it would have fallen below the level
needed for survival and may have remained below that level for some time. With
a population of only about 797 before the eruption, it is unlikely that any group
would have migrated to the North Island by this date – a circumstance that may have
protected the first colony from extinction. In the South Island associated tsunamis
and earthquakes may still have been perilous.