To extend climate information back in time, we investigate the climate sensitivity of a δ¹⁸O network from tree rings, consisting of 26 European sites and covering the last 400 years. Our results suggest that the δ¹⁸O variability is associated with large-scale anomaly patterns that resemble those observed for the El Niño–Southern Oscillation. We conclude that the investigation of large-scale climate signals far beyond instrumental records can be done with a δ¹⁸O network derived from tree rings.

It is not clear to what extent or in what manner a strong volcanic eruption will influence temperature in different regions over the long term. Therefore, new 635-year annual mean minimum temperatures (T_min) across the eastern central Tibetan Plateau were used to explored the response of T_min to strong volcanic eruptions. Our results show that there is a high probability that the T_min decreases within 2 years of a large volcanic eruption, especially when such eruptions occur in low latitudes.

An updated Last Millennium Reanalysis is presented, using an expanded multi-proxy database, and proxy models representing the seasonal characteristics of proxy records, in addition to the dual sensitivity to temperature and moisture of tree-ring-width chronologies. We show enhanced skill in spatial reconstructions of key climate variables in the updated reanalysis, compared to an earlier version, resulting from the combined influences of the enhanced proxy network and improved proxy modeling.

This PAGES (Past Global Changes) 2k (climate of the past 2000 years working group) special issue of Climate of the Past brings together the latest understanding of regional change and impacts from PAGES 2k groups across a range of proxies and regions. The special issue has emerged from a need to determine the magnitude and rate of change of regional and global climate beyond the timescales accessible within the observational record.

This paper reviews the current knowledge of Arctic hydroclimate variability during the past 2000 years. We discuss the current state, look into the future, and describe various archives and proxies used to infer past hydroclimate variability. We also provide regional overviews and discuss the potential of furthering our understanding of Arctic hydroclimate in the past. This paper summarises the hydroclimate-related activities of the Arctic 2k group.