Climate variability in subarctic area for the last two millennia
Marie Nicolle1, Maxime Debret1, Nicolas Massei1, Christophe Colin2, Anne deVernal3, Dmitry Divine4,5, Johannes P. Werner6, Anne Hormes7, Atte Korhola8, and Hans W. Linderholm91Normandie Univ, UNIROUEN, UNICAEN, CNRS, M2C, 76000 Rouen, France 2GEOPS, CNRS, University of Paris-Sud, 91405 Orsay Cedex, France 3Centre de recherche en géochimie et géodynamique (Geotop), Université du Québec à Montréal, Montréal, QC, Canada 4Norwegian Polar Institute, Tromsø, Norway 5Department of Mathematics and Statistics, Arctic University of Norway, Tromsø, Norway 6Bjerknes Center for Climate Research and Department of Earth Science, University of Bergen, Bergen, Norway 7University of Gothenburg, Department of Earth Sciences, Gothenburg, Sweden 8Department of Environmental Sciences, Environmental Change Research Unit (ECRU), University of Helsinki, P.O. Box 65, 00014 Helsinki, Finland 9Regional Climate Group, Department of Earth Sciences, University of Gothenburg, 40530 Gothenburg, Sweden
Received: 10 Mar 2017 – Accepted for review: 15 Mar 2017 – Discussion started: 31 Mar 2017
Abstract. To put in perspective the recent climate change, it is necessary to extend the instrumental climate records with proxy data from palaeoclimate archives. Arctic climate variability for the last two millennia has been investigated using statistical and signal analyses from three regionally averaged records from the North Atlantic, Siberia and Alaska based on many sort of proxy data archived in the Arctic 2k database. In the North Atlantic and Alaska areas, the major climatic trend is characterized by long-term cooling interrupted by the recent warming that started at the beginning of the 19th century. This cooling trend is not clearly visible in the Siberian region. The Little Ice Age (LIA) was identified from the individual series and is characterized by an important spatial and temporal expression of climate variability. It started at the earliest by around 1200 AD and ended at the latest in the middle of the 20th century. The large spread temporal coverage of LIA did not show regional consistency or particular spatial distribution and did not show relationship with archive/proxy type either. A focus on the last two centuries shows a recent warming characterized by a well-marked warming trend paralleling with increasing greenhouse gas emissions. It also shows a multi-decadal variability likely due to natural processes acting on the internal climate system variability at regional scale. A 16–30 years cycle is found in Alaska and seems to be linked to the Pacific Decadal Oscillation (PDO) whereas ~ 20–30 and ~ 50–90 years periodicities characterize the North Atlantic climate regime, likely in relation with the Atlantic Multidecadal Oscillation (AMO). These regional features are apparently linked to the sea-ice cover fluctuations through ice-temperature positive feedback.
Nicolle, M., Debret, M., Massei, N., Colin, C., deVernal, A., Divine, D., Werner, J. P., Hormes, A., Korhola, A., and Linderholm, H. W.: Climate variability in subarctic area for the last two millennia, Clim. Past Discuss., doi:10.5194/cp-2017-33, in review, 2017.