19.11 El Niño-Driven Migration in the Pacific
343
as an extreme example of the discrepancy in climate between the two hemispheres.
Contrasting the history of Norse and Polynesian voyaging and migrations before and
during the Medieval Climatic Optimum (cf. Chapter 12) supports this interpretation.
The annual precision of the El Niño dates and the wider bounds of generational
dating will have only a broad consilience because their bounds apply so differently.
Generation lengths vary from one generation to the next and the overall generation length average will hide many anomalies. Some of the suggested dates for the
Navigators’ Line are exact, that is, they closely match the El Niño events closest
to generational estimates, as, for example, for Kahukura and Hoaki and Taukata.
Without undermining the overall usefulness of the suggested chronology, others,
those for Maru and Tangiia for example, will not. In an archaeological context in
which, as Kirch and Green note, “fully 80 percent of the reconstructed Ancestral
Polynesian artifact array is missing from our archaeological assemblage” [16] ,the
chronology we have sketched can be seen as contributing to the available dating evidence. It is interesting to note the broad agreement of some of the dating estimates
of Smith, Tregear and Fornander with ours, though their estimates were derived
without the benefit of El Niño or eclipse datings. That this is possible suggests
the reliability of well-preserved traditional histories and of the genealogies that
underpin them and the inherent value of both as historical sources.
19.11 El Niño-Driven Migration in the Pacific
The global climate patterns, and especially the recurrence of El Niño-driven
droughts that we have seen as shaping the prehistory of Eastern Polynesia in this
late warm period, must have found an echo in all the populated archipelagoes of
the tropical Pacific. Repeating patterns of conflict over land and resources, linked to
drought, will time and again have made migration mandatory for the defeated and
starving. In other words, in the Medieval Climatic Optimum, it is hardly surprising
that the pulse of long-distance migration and, possibly to a lesser extent, the pulse of
exploration and trading activities in the Pacific were tied to very strong to extreme
ENSO events. The Hawaiians assumed that Captain Cook and his crew were driven
to explore the Pacific by famine. This assumption suggests a very long acquaintance
with famine in tropical Polynesia. Very strong to extreme El Niño events would
have been needed to trigger droughts severe enough to precipitate long-distance
migrations. Likely timings for long-distance drought-driven migrations can be read
from Fig. 19.1. However, as we stressed in Chapter 12, population size in relation
to resources is of key importance in the generation of demographic stress and consequent migration. On a small island with limited resources, less severe drought,
triggered by a lower level El Niño, may have been sufficient to necessitate migration, though this may have involved only local or short-distance migration or the
establishment of a temporary settlement on a small uninhabited island in the region.
The pattern we have observed for the 1,400-year span from Tu-te-rangi-marama
to the southern migrations to Hawaii clearly holds for the period of the Navigators’
343
as an extreme example of the discrepancy in climate between the two hemispheres.
Contrasting the history of Norse and Polynesian voyaging and migrations before and
during the Medieval Climatic Optimum (cf. Chapter 12) supports this interpretation.
The annual precision of the El Niño dates and the wider bounds of generational
dating will have only a broad consilience because their bounds apply so differently.
Generation lengths vary from one generation to the next and the overall generation length average will hide many anomalies. Some of the suggested dates for the
Navigators’ Line are exact, that is, they closely match the El Niño events closest
to generational estimates, as, for example, for Kahukura and Hoaki and Taukata.
Without undermining the overall usefulness of the suggested chronology, others,
those for Maru and Tangiia for example, will not. In an archaeological context in
which, as Kirch and Green note, “fully 80 percent of the reconstructed Ancestral
Polynesian artifact array is missing from our archaeological assemblage” [16] ,the
chronology we have sketched can be seen as contributing to the available dating evidence. It is interesting to note the broad agreement of some of the dating estimates
of Smith, Tregear and Fornander with ours, though their estimates were derived
without the benefit of El Niño or eclipse datings. That this is possible suggests
the reliability of well-preserved traditional histories and of the genealogies that
underpin them and the inherent value of both as historical sources.
19.11 El Niño-Driven Migration in the Pacific
The global climate patterns, and especially the recurrence of El Niño-driven
droughts that we have seen as shaping the prehistory of Eastern Polynesia in this
late warm period, must have found an echo in all the populated archipelagoes of
the tropical Pacific. Repeating patterns of conflict over land and resources, linked to
drought, will time and again have made migration mandatory for the defeated and
starving. In other words, in the Medieval Climatic Optimum, it is hardly surprising
that the pulse of long-distance migration and, possibly to a lesser extent, the pulse of
exploration and trading activities in the Pacific were tied to very strong to extreme
ENSO events. The Hawaiians assumed that Captain Cook and his crew were driven
to explore the Pacific by famine. This assumption suggests a very long acquaintance
with famine in tropical Polynesia. Very strong to extreme El Niño events would
have been needed to trigger droughts severe enough to precipitate long-distance
migrations. Likely timings for long-distance drought-driven migrations can be read
from Fig. 19.1. However, as we stressed in Chapter 12, population size in relation
to resources is of key importance in the generation of demographic stress and consequent migration. On a small island with limited resources, less severe drought,
triggered by a lower level El Niño, may have been sufficient to necessitate migration, though this may have involved only local or short-distance migration or the
establishment of a temporary settlement on a small uninhabited island in the region.
The pattern we have observed for the 1,400-year span from Tu-te-rangi-marama
to the southern migrations to Hawaii clearly holds for the period of the Navigators’