Climate Dynamics

, Volume 41, Issue 7–8, pp 2039–2060 | Cite as

Pairwise comparisons to reconstruct mean temperature in the Arctic Atlantic Region over the last 2,000 years

  • Sami HanhijärviEmail author
  • Martin P. Tingley
  • Atte Korhola


Existing multi-proxy climate reconstruction methods assume the suitably transformed proxy time series are linearly related to the target climate variable, which is likely a simplifying assumption for many proxy records. Furthermore, with a single exception, these methods face problems with varying temporal resolutions of the proxy data. Here we introduce a new reconstruction method that uses the ordering of all pairs of proxy observations within each record to arrive at a consensus time series that best agrees with all proxy records. The resulting unitless composite time series is subsequently calibrated to the instrumental record to provide an estimate of past climate. By considering only pairwise comparisons, this method, which we call PaiCo, facilitates the inclusion of records with differing temporal resolutions, and relaxes the assumption of linearity to the more general assumption of a monotonically increasing relationship between each proxy series and the target climate variable. We apply PaiCo to a newly assembled collection of high-quality proxy data to reconstruct the mean temperature of the Northernmost Atlantic region, which we call Arctic Atlantic, over the last 2,000 years. The Arctic Atlantic is a dynamically important region known to feature substantial temperature variability over recent millennia, and PaiCo allows for a more thorough investigation of the Arctic Atlantic regional climate as we include a diverse array of terrestrial and marine proxies with annual to multidecadal temporal resolutions. Comparisons of the PaiCo reconstruction to recent reconstructions covering larger areas indicate greater climatic variability in the Arctic Atlantic than for the Arctic as a whole. The Arctic Atlantic reconstruction features temperatures during the Roman Warm Period and Medieval Climate Anomaly that are comparable or even warmer than those of the twentieth century, and coldest temperatures in the middle of the nineteenth century, just prior to the onset of the recent warming trend.


Multiproxy reconstruction Pairwise comparisons Non-linear method North Atlantic Temperature 



This study is part of the IGBP PAGES Arctic2k project. We thank IGBP PAGES for supporting the Arctic2k workshops. We thank the reviewers for their suggestions and comments. We thank Darrell Kaufman, Dmitry Divine, Fredrik Charpentier Ljungqvist, Håkan Grudd, and Samuli Helama for helping to collect proxy records. We also thank all the individual authors who provided us with records.

Authors' contribution

SH and AK designed the overall research. SH designed and implemented PaiCo; assembled data sets and carried out all analyzes; and was primarily responsible for preparation of the manuscript. MPT contributed to the design of the quantitative comparisons and interpretation of results, and to the preparation of the manuscript. AK contributed to the interpretation of results and to the preparation of the manuscript.

Supplementary material (999 kb)
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Copyright information

© Springer-Verlag Berlin Heidelberg 2013

Authors and Affiliations

  • Sami Hanhijärvi
    • 1
    Email author
  • Martin P. Tingley
    • 2
  • Atte Korhola
    • 1
  1. 1.Department of Environmental SciencesUniversity of HelsinkiHelsinkiFinland
  2. 2.Department of Earth and Planetary SciencesHarvard UniversityCambridgeUSA

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