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Ref ID: 34400
Ref Type: Journal Article
Authors: Richerson, Peter J.
Boyd, Robert
Bettinger, Robert L.
Title: Was agriculture impossible during the Pleistocene but mandatory during the Holocene? A climate change hypothesis
Date: 2001
Source: American Antiquity
Notes: hypothesizes that (p.404) "reduction in climate variability, increase in CO2 content in the atmosphere, and increases in rainfall rather abruptly changed the earth from a regime where agriculture was impossible to one where it was possible in many places." Discusses factors that affect variation in tempo of the change to intensified plant strategies. Suggests that variable climate in Pleistocene forced opportunistic subsistence strategies. Says p.398) that innovation will precede evidence for increased population pressure.
Abstract: Several independent trajectories of subsistence intensification, often leading to agriculture, began during the Holocene. No plant-rich intensifications are known from the Pleistocene, even from the late Pleistocene when human populations were otherwise quite sophisticated. Recent data from ice and ocean-core climate proxies show that last glacial climates were extremely hostile to agriculture¬ódry, low in atmospheric CO<sub>2</sub> and extremely variable on quite short time scales. We hypothesize that agriculture was impossible under last-glacial conditions. The quite abrupt final amelioration of the climate was followed immediately by the beginnings of plant-intensive resource-use strategies in some areas, although the turn to plants was much later elsewhere. Almost all trajectories of subsistence intensification in the Holocene are progressive, and eventually agriculture became the dominant strategy in all but marginal environments. We hypothesize that, in the Holocene, agriculture was, in the long run, compulsory. We use a mathematical analysis to argue that the rate-limiting process for intensification trajectories must generally be the rate of innovation of subsistence technology or subsistence-related social organization. At the observed rates of innovation, popular growth will always be rapid enough to sustain a high level of population pressure. Several processes appear to retard rates of cultural evolution below the maxima we observe in the most favorable cases.
Date Created: 7/31/2001
Volume: 66
Number: 3
Page Start: 387
Page End: 411