资源环境科技发展态势分析平台

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 delta O-18 and six ring width chronologies. Until now, these chronologies have only been used in independent temperature reconstructions (from delta O-18 or ring width) showing some differences. Here, we added to the dataset a delta C-13 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, delta O-18 showed intermediate responses, and delta C-13 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.