Inconsistent comparison of temperature reconstructions over the Common Era

Neukom, Raphael; Steiger, Nathan; Kaufman, Darrell; Grosjean, Martin (2022). Inconsistent comparison of temperature reconstructions over the Common Era. Dendrochronologia, 74, p. 125965. Elsevier 10.1016/j.dendro.2022.125965

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Büntgen et al. (2020) present a new reconstruction of extra-tropical summer temperatures based on updated versions of a large number of summer temperature sensitive tree-ring width chronologies from the Northern Hemisphere (NH), which cover the full Common Era (CE). This new dataset allows the authors to draw conclusions about NH temperature history and its relation to climate forcing, marking an important contribution to our understanding of past climate changes. While we have no issues with the main conclusions of B20, here we show that their comparison with PAGES 2k reconstructions is flawed: B20′s reconstruction focused on regional, summertime temperature, while the PAGES 2k reconstruction targeted global, annual mean temperature. For their reconstruction intercomparisons, B20 rescale all six tree-ring based reconstructions to their regional observational target but fail to do this same processing step with the PAGES 2k reconstructions. This inconsistent comparison leads B20 to incorrectly conclude that the PAGES 2k reconstructions severely lack variance and are therefore unreliable. In this contribution, we present a consistent comparison of the B20 and PAGES 2k reconstructions, and we highlight the importance of careful illustrations for interpreting scientific results both in the literature and in the public discussion. Our results show that, if more accurate methods for comparisons are applied, the temperature history and low-frequency amplitudes of the different proxy selection approaches and reconstruction products are not at odds, but actually consistent with the differences between their targets over the pre-industrial CE.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Institute of Geography > Physical Geography > Unit Paleolimnology
10 Strategic Research Centers > Oeschger Centre for Climate Change Research (OCCR)
08 Faculty of Science > Institute of Geography
08 Faculty of Science > Institute of Geography > Physical Geography

UniBE Contributor:

Grosjean, Martin

Subjects:

500 Science > 550 Earth sciences & geology
900 History > 910 Geography & travel

ISSN:

1125-7865

Publisher:

Elsevier

Language:

English

Submitter:

Giulia Luise Wienhues

Date Deposited:

07 Jun 2022 14:25

Last Modified:

05 Dec 2022 16:20

Publisher DOI:

10.1016/j.dendro.2022.125965

BORIS DOI:

10.48350/170357

URI:

https://boris.unibe.ch/id/eprint/170357

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