Bayesian multiproxy temperature reconstruction with black spruce ring widths and stable isotopes from the northern Quebec taiga

• Published in: Climate Dynamics
• Main Authors: GENNARETTI, Fabio, David, Huard, Maud, Naulier, Savard, Martine M., Begin, Christian, Arseneault, Dominique, Guiot, Joel
• Other Authors: Centre européen de recherche et d'enseignement des géosciences de l'environnement (CEREGE), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Collège de France (CdF (institution))-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA), Ouranos, Consortium on Regional Climate Change and Adaptation to Climate change, Institut de Radioprotection et de Sûreté Nucléaire (IRSN), Geological Survey of Canada Québec (GSC Québec), Geological Survey of Canada - Office (GSC), Natural Resources Canada (NRCan)-Natural Resources Canada (NRCan), Université du Québec à Rimouski (UQAR)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2017
• Subjects: Summer temperature; Volcanic impact; Proxy sensitivity; Tree-ring; Oxygen isotopes; Carbon isotopes; Last millennium; [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces; environment; [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology; taiga
• Online Access: https://hal.archives-ouvertes.fr/hal-01586016; https://hal.archives-ouvertes.fr/hal-01586016/document; https://hal.archives-ouvertes.fr/hal-01586016/file/2017-Gennaretti_et_al-2017-Climate_Dynamics.pdf; https://doi.org/10.1007/s00382-017-3565-5

International audience Northeastern North America has very few millennium-long, high-resolution climate proxy records. However, very recently, a new tree-ring dataset suitable for temperature reconstructions over the last millennium was developed in the northern Quebec taiga. This dataset is composed of one δ18O and six ring width chronologies. Until now, these chronologies have only been used in independent temperature reconstructions (from δ18O or ring width) showing some differences. Here, we added to the dataset a δ13C chronology and developed a significantly improved millennium-long multiproxy reconstruction (997–2006 CE) accounting for uncertainties with a Bayesian approach that evaluates the likelihood of each proxy model. We also undertook a methodological sensitivity analysis to assess the different responses of each proxy to abrupt forcings such as strong volcanic eruptions. Ring width showed a larger response to single eruptions and a larger cumulative impact of multiple eruptions during active volcanic periods, δ18O showed intermediate responses, and δ13C was mostly insensitive to volcanic eruptions. We conclude that all reconstructions based on a single proxy can be misleading because of the possible reduced or amplified responses to specific forcing agents.