A comparison of drought information in early North American colonial documentary records and a high-resolution tree-ring-based reconstruction

Sam White

doi:10.5194/cp-15-1809-2019

Abstract

Abstract. Historical documentary records contain valuable information on climate, weather, and their societal impacts during the pre-instrumental period, but it may be difficult to assess the objectivity and reliability of this information, particularly where the documentary record is incomplete or the reliability of the information it contains is uncertain. This article presents a comprehensive review of information relating to drought found in original written records concerning all early European expeditions (1510–1610 CE) into the present-day US and Canada, and compares this information with maps and time series of drought generated from the tree-ring-based North American Drought Atlas (NADA). The two sources mostly agree in the timing and location of droughts. This correspondence suggests that much of the information in these early colonial historical records is probably objective and reliable, and that tree-ring-based drought atlases can provide information relevant to local and regional human historical events, at least in locations where their reconstruction skill is particularly high. This review of drought information from written sources and tree-ring-based reconstructions also highlights the extraordinary challenges faced by early European explorers and colonists in North America due to climatic variability in an already unfamiliar and challenging environment.

Highlights

Regional climatic variability before the instrumental period, including the frequency and severity of historical droughts, may be reconstructed through analysis of proxies preserved in natural archives or of proxies and descriptions in written records
The North American Drought Atlas (NADA) Palmer Drought Severity Index (PDSI) reconstruction indicates drought in New England during 1603, when an English voyage passed by the Massachusetts coast in summer, and in 1604, when a French colony was founded at the mouth of the St
A few survivors remained in the region as captives of Native Americans until 1534; their testimonies, recorded years later, described cold and famine among the indigenous populations but left no definite indications of drought during these years

Summary

Introduction

Regional climatic variability before the instrumental period, including the frequency and severity of historical droughts, may be reconstructed through analysis of proxies preserved in natural archives (paleoclimatology) or of proxies and descriptions in written records (historical climatology). Most historical regions and periods lack such abundant and consistent written records before the instrumental period In these cases, historical observers tend to act as a “high-pass filter” recording mostly extreme events and/or as degraded archives preserving scattered periodic climate proxies and descriptions (Bradley, 2015). Historical observers tend to act as a “high-pass filter” recording mostly extreme events and/or as degraded archives preserving scattered periodic climate proxies and descriptions (Bradley, 2015) These written records remain potentially valuable for climate history since they contain information unavailable from proxies in natural archives, including precisely located and dated climate and weather events from all seasons and their societal impacts (Brönniman et al, 2018). These same observers were unfamiliar with their new colonial

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