Global interdecadal and century-scale climate oscillations during the past five centuries

THE recognition of natural modes of climate variability is essential for a better understanding of the factors that govern climate change. Recent models suggest that interdecadal (roughly 15–35-year period)^1–4 and century-scale (roughly 50–150-year period)^5–7 climate variability may be intrinsic to the natural climate system. While there is some evidence for the existence of interdecadal^8,9 and century-scale^9,10 oscillations in instrumental temperature records, confident detection from these short (100–400-year) records is difficult^11,12. Oscillations on the same timescales^5,13–17 have also been detected in isolated climate-proxy or historical records over longer durations, but the large-scale spatial structure of the variability has not been investigated systematically. Here we report the multivariate analysis of a globally distributed set of temperature proxy records of several centuries duration. The results of our spatio-temporal analysis strengthen evidence for persistent natural interdecadal and century-scale climate oscillations, and reveal both the spatial patterns and temporal histories of these signals.