Climatic change, culture, and civilization in North America

Abstract

Analysis of modern climatic data suggests a pattern of response to global cooling for precipitation in Mesoamerica and North America. Also research in palaeoclimatology has defined a series of globally warm and cold periods for the Holocene. This paper joins the study of modern and palaeoclimate into a time-series model which appears to explain some of the florescences and declines of civilizations in the region during the last 3,000 years. Economic buffering and local invulnerability to climatic change for specifiable reasons appear to cover those cases which defy climatic explanation. Article: The potential threat that climatic change poses to twentieth-century world civilization has fostered massive efforts by many palaeoclimatic researchers over the last decade and added a considerable amount of detail to our knowledge of the sequence of climatic events, particularly over the last 10,000 years (National Academy of Science 1975, Quaternary Research issue July 1979). In this paper the details of climatic chronology of the northern hemisphere are compared to the cultural chronologies of Mesoamerica and North America. When the beginnings and ends of outstanding periods of civilized activity are compared with climatic changes, these events in many instances appear to correspond. In the cases where they do not, alternative explanations are often satisfactory; that is, the effects of economic buffering and invulnerability to climatic change due to favourable local conditions. The detailed histories and prehistories of many North American civilizations offer interesting sequences of interaction in the give-and-take battle between urban man and the forces of nature. We do not undertake the arduous task of proving in a concrete sense the cause-and-effect relationships between culture change and climatic change in North America. On the other hand, we do propose what we feel to be a reasonable array of relationships which can be tested by regional specialists. The issue of environmental effects on people and social groups or cultures has been debated from time to time, so perhaps it is advisable to make explicit assumptions concerning culture change and environment. As is indicated in figure 1, we assumed that culture change is fostered by at least three forcing variables, of which environment is one. The amount of culture change observable over a given period in time may be attributable to any one or all, or any continuation of the forcing variables. Also, the proportion of contribution is variable, X per cent, Y per cent and Z per cent. Thus, when climate is changing radically, culture change may be accounted for almost wholly in terms of X per cent. On the other hand, during times of climatic stability, changes are attributable to internal forces such as powerful individuals in a proportion of Y per cent, or to external sources such as invasion by outsiders, Z per cent.

Wetland fields as mirrors of drought and the Maya abandonment

“…Scholars began to suspect the role of drought in Maya history by associating Mesoamerican with European trends (21,22), but the first regional evidence came in the 1990s based on retrodicting the discharge of the Rio Candelaria, Mexico, with models of global insolation, atmospheric patterns, and volcanic emissions that indicated higher rainfall in the Classic Period and dryer conditions in the Terminal Classic (23,24). Lake core studies at Chichancanab and Punta Laguna, also in the 1990s, indicated climate change in the Yucatán based on the relative abundance of sulfur (S) to calcite (CaCO 3 ) in sediments and oxygen isotope ratios (δ 18 O) in benthic shells (25)(26)(27)(28).…”

Bajo Sediments and the Hydraulic System of Calakmul, Campeche, Mexico

“…Its combination of prepared watersheds, bajo-edge reservoirs, and neighborhood reservoirs (Scarborough and Gallopin 1991) seems to reflect an intermediate level of design between the intense centralization of Edzna and Calakmul's extreme modularization. The modularization of Calakmul's hydrological system, we believe, represents at least part of a solution for adapting to interior upland environments without permanent water sources until the ninth century, when a lack of adequate seasonal rainfall contributed to the downfall of this unique system (Folan 1981;Gunn and Adams 1981;Gunn et al 1994Gunn et al , 1995Hodell et al 1995).…”

“…Although 30 km 2 of the city have been mapped, it may be as large as 70 km 2 (Folan et al 1995). The floor of the El Laberinto bajo was occupied after a.d. 200, apparently when the bajo waters were at dependably low levels because of an extended drought (Folan 1981;Gunn and Adams 1981;Gunn et al 1994Gunn et al , 1995Hodell et al 1995). Stone platforms and stone-rimmed, elevated fields suggest that it was used for agricultural production, and stone-rimmed and 298 Gunn et al lined reservoirs raised above the level of the bajo bottom mark water storage.…”

“…Over the past two decades, we have explored diverse horticultural customs and variability in river discharge in the state of Campeche, Mexico, and their teleconnected relationships with global climatechange issues (Folan et al 1983;Gunn and Adams 1981;Gunn et al 1994Gunn et al , 1995. The Candelaria River system, which drains about half of Campeche, shows the strongest statistical relationship to cyclical global-climate parameters of any watershed we have examined anywhere in the world thus far .…”

Introduction: A perspective from the humanities-science boundary

“…Cool global climate brings dank, moist climate to Europe which leaches soil nutrients and impedes harvests of grain crops. On the Yucatan Peninsula, globally cool climate fosters ideal agricultural conditions for corn (Gunn and Adams, 1981;Gunn et al, 1993).…”