12.4 A North American Analogue
199
remembered and he is known today as Ike ne kai he kuma he mate pipili, or ‘The king
that was food for the rats when he was starving’.
In isolated islands, such as those of tropical Polynesia, food resources are
constrained by land area and by the limits of horticultural technology. When
highly populated, such islands are particularly vulnerable to climate extremes.
Their boom/bust demographic patterns have been commented on by demographers.
Alexandra Brewis and John Allen, for example, comment: “One characteristic of
Pacific populations which may set them apart from other populations is a long-term
tendency towards growth, coupled with habitual periodic population collapses, most
particularly under atolline conditions” [11]. The extinction of species at each crisis
point through over-hunting and over-fishing renders an island permanently poorer,
less able to support high populations. The terrible example of the devastation of the
ecology of Easter Island shows the process close to end-point.
12.4 A North American Analogue
We can set the resource crisis faced by tropical Polynesia in the Medieval Climatic
Optimum in a wider context by considering a paper published by Terry Jones and
15 other authors in 1999 [12]. This paper provides a detailed North American analogue for the drought-driven demographic crisis that faced Eastern Polynesia during
the Medieval Climatic Optimum. The beginning of their abstract provides a quick
summary of their thesis:
Review of late Holocene paleoenvironmental and cultural sequences from four regions
of western North America shows striking correlations between drought and changes in
subsistence, population, exchange, health, and interpersonal violence during the Medieval
Climatic Anomaly (A.D. 800–1350). While ultimate causality is difficult to identify in the
archaeological record, synchrony of the environmental and cultural changes and the negative character of many human responses—increased interpersonal violence, deterioration
of long-distance exchange relationships, and regional abandonments—suggest widespread
demographic crises caused by decreased environmental productivity. The medieval droughts
occurred at a unique juncture in the demographic history of western North America when
unusually large populations of both hunter-gatherers and agriculturalists had evolved highly
intensified economies that put them in unprecedented ecological jeopardy (p. 137).
The authors comment that the Medieval Climatic Anomaly
was a time of increased aridity that coincided with a unique pattern of demographic stress
and frequent economic crises across much of western North America. Large populations
of agriculturalists and hunter-gatherers were confronted with serious and abrupt declines
in productivity caused by repeated and prolonged droughts. . .We believe that the plethora
of cultural changes and the negative character of many of them reflect widespread crises
related to population/resource imbalances, drought-related environmental deterioration, and
shortages of food and water (p. 138).
They argue that the period between AD 800 and AD 1350 was punctuated by
“epic droughts” and that these droughts “and the more broadly timed episodes of
increased temperatures attendant upon the Medieval Climatic Anomaly had direct
effects on terrestrial ecosystems by impacting water sources and reducing primary
production and therefore harvestable biomass” (p. 138).
199
remembered and he is known today as Ike ne kai he kuma he mate pipili, or ‘The king
that was food for the rats when he was starving’.
In isolated islands, such as those of tropical Polynesia, food resources are
constrained by land area and by the limits of horticultural technology. When
highly populated, such islands are particularly vulnerable to climate extremes.
Their boom/bust demographic patterns have been commented on by demographers.
Alexandra Brewis and John Allen, for example, comment: “One characteristic of
Pacific populations which may set them apart from other populations is a long-term
tendency towards growth, coupled with habitual periodic population collapses, most
particularly under atolline conditions” [11]. The extinction of species at each crisis
point through over-hunting and over-fishing renders an island permanently poorer,
less able to support high populations. The terrible example of the devastation of the
ecology of Easter Island shows the process close to end-point.
12.4 A North American Analogue
We can set the resource crisis faced by tropical Polynesia in the Medieval Climatic
Optimum in a wider context by considering a paper published by Terry Jones and
15 other authors in 1999 [12]. This paper provides a detailed North American analogue for the drought-driven demographic crisis that faced Eastern Polynesia during
the Medieval Climatic Optimum. The beginning of their abstract provides a quick
summary of their thesis:
Review of late Holocene paleoenvironmental and cultural sequences from four regions
of western North America shows striking correlations between drought and changes in
subsistence, population, exchange, health, and interpersonal violence during the Medieval
Climatic Anomaly (A.D. 800–1350). While ultimate causality is difficult to identify in the
archaeological record, synchrony of the environmental and cultural changes and the negative character of many human responses—increased interpersonal violence, deterioration
of long-distance exchange relationships, and regional abandonments—suggest widespread
demographic crises caused by decreased environmental productivity. The medieval droughts
occurred at a unique juncture in the demographic history of western North America when
unusually large populations of both hunter-gatherers and agriculturalists had evolved highly
intensified economies that put them in unprecedented ecological jeopardy (p. 137).
The authors comment that the Medieval Climatic Anomaly
was a time of increased aridity that coincided with a unique pattern of demographic stress
and frequent economic crises across much of western North America. Large populations
of agriculturalists and hunter-gatherers were confronted with serious and abrupt declines
in productivity caused by repeated and prolonged droughts. . .We believe that the plethora
of cultural changes and the negative character of many of them reflect widespread crises
related to population/resource imbalances, drought-related environmental deterioration, and
shortages of food and water (p. 138).
They argue that the period between AD 800 and AD 1350 was punctuated by
“epic droughts” and that these droughts “and the more broadly timed episodes of
increased temperatures attendant upon the Medieval Climatic Anomaly had direct
effects on terrestrial ecosystems by impacting water sources and reducing primary
production and therefore harvestable biomass” (p. 138).