Drought during early European exploration and colonization of North America, 1500–1610CE: A comparison of evidence from the archives of societies and the archives of nature (original) (raw)

2019, Climate of the Past Discussions

This article presents the historical evidence concerning the occurrence of drought in North America from 1510-1610CE based on a comprehensive review of original written records concerning all early European expeditions into the present US and Canada. It compares this evidence from the archives of societies with maps and time series of drought generated from the tree ring-based North American Drought Atlas (NADA). This comparison demonstrates the reliability of 10 early colonial historical records as sources of evidence concerning drought, as well as the applicability of the NADA to the scale of local and regional human historical events. The comparison further verifies the occurrence and societal impacts of certain major droughts previously identified in dendroclimatological studies, but suggests that some summer hydrological deficits indicated in the tree ring record reflect a deficiency of summer rather than winter precipitation. Finally, this review of evidence from both the archives of societies and archives of nature highlights the extraordinary challenges faced by early 15 European explorers and colonists in North America due to climatic variability in an already unfamiliar and challenging environment. 1 Introduction The frequency and severity of regional droughts before the instrumental period may be reconstructed on the basis of either the archives of nature or the archives of societies. The former, which comprise natural records containing proxies for precipitation 20 or soil moisture, such as tree ring width or isotopic variations in speleothem layers, are usually employed for the more distant past and for world regions without detailed historical records. The latter, which comprise descriptions and observations of natural phenomena left by people, are usually employed for the past five to six centuries in regions with abundant personal records and official archives, such as Western Europe and China. In some cases, however, reconstructions of both types may be combined or compared in order to achieve a level of continuity, homogeneity, resolution, spatial extent and/or seasonal 25 coverage lacking in one type of archive alone, as well as to cross-check their respective results. This approach may be particularly useful where the archives of societies are plentiful enough to provide useful data but insufficient for a complete independent reconstruction of historical drought (e.g., Mendoza et al., 2006; Stahle et al., 2007). This article presents the evidence concerning the occurrence and the human impacts of droughts in North America (present US and Canada) during the first century of European exploration and colonization of the continent, 1510-1610CE, 30 based on an original comprehensive review of the primary historical sources for those expeditions. It compares this evidence from the archives of societies with drought reconstructions based on archives of nature, principally reconstructions of summer Palmer drought severity index (PDSI) from the tree ring-based North American Drought Atlas (NADA). This reconstruction and comparison serves the following four purposes: (1) to test the objectivity and reliability of these historical observations, and thus the potential for exploration and colonization records to be used in drought reconstruction; (2) to crosscheck the 35 NADA reconstructions-including those for extreme events reconstructed during the 16 th and early 17 th centuries-and the NADA's applicability to the scale of human historical events; (3) to gain further insights into the seasonality and severity of historical droughts found in each type of evidence; and (4) to better understand the human impacts of droughts during this critical and vulnerable phase of North American exploration and colonization. By 1610-with the foundation of enduring