Narrative evidence contained within historical documents and inscriptions provides an important record of climate variability for periods prior to the onset of systematic meteorological data collection. A common approach used by historical climatologists to convert such qualitative information into continuous quantitative proxy data is through the generation of ordinal-scale climate indices. There is, however, considerable variability in the types of phenomena reconstructed using an index approach and the practice of index development in different parts of the world. This review, written by members of the PAGES (Past Global Changes) CRIAS working group - a collective of climate historians and historical climatologists researching Climate Reconstructions and Impacts from the Archives of Societies - provides the first global synthesis of the use of the index approach in climate reconstruction. We begin by summarising the range of studies that have used indices for climate reconstruction across six continents (Europe, Asia, Africa, the Americas, and Australia) as well as the world's oceans. We then outline the different methods by which indices are developed in each of these regions, including a discussion of the processes adopted to verify and calibrate index series, and the measures used to express confidence and uncertainty. We conclude with a series of recommendations to guide the development of future index-based climate reconstructions to maximise their effectiveness for use by climate modellers and in multiproxy climate reconstructions.
Bibliographical noteFunding Information:
Financial support. The meetings that underpinned this article were supported by PAGES (Past Global Changes). The article processing charges for this open-access publication were covered by the Freigeist Fellowship “The Dantean Anomaly (1309–1321)” (funded by the Volkswagen Foundation) and the Education University of Hong Kong.
© Author(s) 2021. This work is distributed under the Creative Commons Attribution 4.0 License.
- Climate reconstruction
- temperature reconstruction
- precipitation reconstruction
- historical climatology
- documentary evidence