Reconstruction and attribution of global multidecadal temperature variability over the last 2000 years — Australian Meteorological and Oceanographic Society
  1. Schedule
  2. 14(i). Palaeoclimates and palaeo-environments: proxies and modelling advances
  3. Reconstruction and attribution of global multidecadal temperature variability over the last 2000 years

Reconstruction and attribution of global multidecadal temperature variability over the last 2000 years (#182)

Raphael Neukom 1 , Luis Barboza 2 , Michael Erb 3 , Feng Shi 4 5 , Julien Emile-Geay 6 , Michael Evans 7 , Jörg Franke 1 , Darrell S Kaufman 3 , Lucie Lücke 8 , Kira Rehfeld 9 10 , Andrew Schurer 8 , Feng Zhu 6 , Stefan Brönnimann 1 , Gregory J Hakim 11 , Benjamin J Henley 12 , Fredrik C Ljungqvist 13 14 15 , Nicholas McKay 3 , Veronika Valler 1 , Lucien von Gunten 16
  1. Oeschger Centre for Climate Change Research and Institute of Geography, University of Bern, Bern, Switzerland
  2. Escuela de Matematica-CIMPA, Universidad de Costa Rica, San Jose, Costa Rica
  3. School of Earth and Sustainability, Northern Arizona University, Flagstaff, AZ, USA
  4. Key Laboratory of Cenozoic Geology and Environment, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, China
  5. CAS Center for Excellence in Life and Paleoenvironment, Beijing, China
  6. Departmentof Earth Sciences and Center for Applied Mathematical Sciences, University of Southern California, LosAngeles, CA, USA
  7. Department of Geology and ESSIC, University of Maryland, College Park, MD, USA
  8. School of Geosciences, University of Edinburgh, Edinburgh, United Kingdom
  9. British Antarctic Survey, Cambridge, United Kingdom
  10. Institute of Environmental Physics, Ruprecht-Karls-Universität Heidelberg, Heidelberg, Germany
  11. Department of Atmospheric Sciences, University ofWashington, Seattle, WA, USA
  12. University of Melbourne, Parkville, VIC, Australia
  13. Department of History, Stockholm University, Stockholm, Sweden
  14. Bolin Centre for Climate Research, Stockholm University, Stockholm, Sweden
  15. Department of Geography, University of Cambridge, Cambridge, United Kingdom
  16. PAGES International Project Office, Bern, Switzerland

Multi-decadal surface temperature changes may be forced by natural as well as anthropogenic factors, or arise as unforced internal variability in the climate system. Distinguishing these factors is essential for estimating the sensitivity to climatic forcings and the amplitude of the unforced variability. Here we present 2,000-year-long global mean surface temperature reconstructions using seven different statistical methods that draw from a new global collection of temperature-sensitive paleoclimate records. Our new reconstructions display synchronous multi-decadal temperature fluctuations, which are coherent with one another and with fully forced CMIP5 millennial model simulations across the Common Era. The most significant attribution of pre-industrial variability at multi-decadal timescales is with volcanic aerosol forcing. The largest warming trends at timescales of 20 years and longer occur during the second half of the 20th century, highlighting the unusual character of warming in recent decades. Reconstructions and simulations agree on the magnitude of unforced global mean multi-decedal temperature variability, thereby increasing confidence in the ability of these models to project future decadal-scale climate change and in conservative baseline estimates against which forced variations may be detected.

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