Northern hemisphere temperatures during the past millennium: Inferences, uncertainties, and limitations

1999/03/15 by Michael Mann, Raymond S. Bradley, Malcolm K. Hughes · 55 citations
Earth and Planetary Sciences · Environmental Science · #Tree-ring climate responses #Geology and Paleoclimatology Research #Climate variability and models #Proxy (statistics) #Northern Hemisphere #Climatology #Context (archaeology) #Forcing (mathematics) #Environmental science #Geography #Geology #Archaeology #Computer science

paper · doi:10.1029/1999gl900070

openalex publication_date 1999/03/15 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/01

Abstract

Building on recent studies, we attempt hemispheric temperature reconstructions with proxy data networks for the past millennium. We focus not just on the reconstructions, but the uncertainties therein, and important caveats. Though expanded uncertainties prevent decisive conclusions for the period prior to AD 1400, our results suggest that the latter 20th century is anomalous in the context of at least the past millennium. The 1990s was the warmest decade, and 1998 the warmest year, at moderately high levels of confidence. The 20th century warming counters a millennial‐scale cooling trend which is consistent with long‐term astronomical forcing.

Citations

• Global-scale temperature patterns and climate forcing over the past six centuries
• High-resolution palaeoclimatic records for the last millennium: interpretation, integration and comparison with General Circulation Model control-run temperatures

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