Disentangling the causes of the 1816 European year without a summer

Schurer, Andrew P; Hegerl, Gabriele C; Luterbacher, Jürg; Brönnimann, Stefan; Cowan, Tim; Tett, Simon F B; Zanchettin, Davide; Timmreck, Claudia (2019). Disentangling the causes of the 1816 European year without a summer. Environmental Research Letters, 14(9), 094019. IOP Publishing 10.1088/1748-9326/ab3a10

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The European summer of 1816 has often been referred to as a 'year without a summer' due to anomalously cold conditions and unusual wetness, which led to widespread famines and agricultural failures. The cause has often been assumed to be the eruption of Mount Tambora in April 1815, however this link has not, until now, been proven. Here we apply state-of-the-art event attribution methods to quantify the contribution by the eruption and random weather variability to this extreme European summer climate anomaly. By selecting analogue summers that have similar sea-level-pressure patterns to that observed in 1816 from both observations and unperturbed climate model simulations, we show that the circulation state can reproduce the precipitation anomaly without external forcing, but can explain only about a quarter of the anomalously cold conditions. We find that in climate models, including the forcing by the Tambora eruption makes the European cold anomaly up to 100 times more likely, while the precipitation anomaly became 1.5–3 times as likely, attributing a large fraction of the observed anomalies to the volcanic forcing. Our study thus demonstrates how linking regional climate anomalies to large-scale circulation is necessary to quantitatively interpret and attribute post-eruption variability.

Item Type:

Journal Article (Original Article)


08 Faculty of Science > Institute of Geography > Physical Geography > Unit Climatology
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:

Brönnimann, Stefan


900 History > 910 Geography & travel




IOP Publishing


[4] Swiss National Science Foundation ; [18] European Research Council




André Hürzeler

Date Deposited:

18 Sep 2019 15:06

Last Modified:

26 May 2022 13:44

Publisher DOI:






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