Articles | Volume 14, issue 4
Clim. Past, 14, 473–514, 2018

Special issue: Climate of the past 2000 years: regional and trans-regional...

Clim. Past, 14, 473–514, 2018

Review article 10 Apr 2018

Review article | 10 Apr 2018

Arctic hydroclimate variability during the last 2000 years: current understanding and research challenges

Hans W. Linderholm1, Marie Nicolle2, Pierre Francus3,19, Konrad Gajewski4, Samuli Helama5, Atte Korhola6, Olga Solomina7, Zicheng Yu8, Peng Zhang1, William J. D'Andrea9, Maxime Debret2, Dmitry V. Divine10,18, Björn E. Gunnarson11, Neil J. Loader12, Nicolas Massei2, Kristina Seftigen1,13, Elizabeth K. Thomas14, Johannes Werner15, Sofia Andersson11, Annika Berntsson11, Tomi P. Luoto16, Liisa Nevalainen16, Saija Saarni17, and Minna Väliranta6 Hans W. Linderholm et al.
  • 1Regional Climate Group, Department of Earth Sciences, University of Gothenburg, 40530 Gothenburg, Sweden
  • 2Normandie Univ, UNIROUEN, UNICAEN, CNRS, M2C, 76000 Rouen, France
  • 3Institut National de la Recherche Scientifique, Centre Eau Terre Environnement, G1K 9A9, Québec, QC, Canada
  • 4Département de géographie, Université d'Ottawa, Ottawa, Ontario K1N 6N5, Canada
  • 5Natural Resources Institute Finland, Rovaniemi, Finland
  • 6Environmental Change Research Unit (ECRU), Department of Environmental Sciences, University of Helsinki, 00014 Helsinki, Finland
  • 7Institute of Geography, Russian Academy of Sciences, 119017 Moscow, Russia
  • 8Department of Earth and Environmental Sciences, Lehigh University, Bethlehem PA 18015-3001, USA
  • 9Lamont-Doherty Earth Observatory, Columbia University, Palisades NY 10964, USA
  • 10Norwegian Polar Institute, Fram Centre, 9296 Tromsø, Norway
  • 11Department of Physical Geography, Stockholm University, 10691 Stockholm, Sweden
  • 12Department of Geography, Swansea University, Swansea SA2 8PP, Wales, UK
  • 13Earth and Life Institute, Université catholique de Louvain, 1348 Louvain-la-Neuve, Belgium
  • 14Department of Geology, University at Buffalo, Buffalo NY 14260, USA
  • 15Department of Earth Science, University of Bergen, 5020 Bergen, Norway
  • 16Department of Environmental Sciences, University of Helsinki, 15140 Lahti, Finland
  • 17Department of Geography and Geology, University of Turku, 20014 Turun yliopisto, Finland
  • 18Department of Mathematics and Statistics, University of Tromsø – The Arctic University of Norway, 9037, Norway
  • 19GEOTOP Research Center, Montréal, QC, Canada

Abstract. Reanalysis data show an increasing trend in Arctic precipitation over the 20th century, but changes are not homogenous across seasons or space. The observed hydroclimate changes are expected to continue and possibly accelerate in the coming century, not only affecting pan-Arctic natural ecosystems and human activities, but also lower latitudes through the atmospheric and ocean circulations. However, a lack of spatiotemporal observational data makes reliable quantification of Arctic hydroclimate change difficult, especially in a long-term context. To understand Arctic hydroclimate and its variability prior to the instrumental record, climate proxy records are needed. The purpose of this review is to summarise the current understanding of Arctic hydroclimate during the past 2000 years. First, the paper reviews the main natural archives and proxies used to infer past hydroclimate variations in this remote region and outlines the difficulty of disentangling the moisture from the temperature signal in these records. Second, a comparison of two sets of hydroclimate records covering the Common Era from two data-rich regions, North America and Fennoscandia, reveals inter- and intra-regional differences. Third, building on earlier work, this paper shows the potential for providing a high-resolution hydroclimate reconstruction for the Arctic and a comparison with last-millennium simulations from fully coupled climate models. In general, hydroclimate proxies and simulations indicate that the Medieval Climate Anomaly tends to have been wetter than the Little Ice Age (LIA), but there are large regional differences. However, the regional coverage of the proxy data is inadequate, with distinct data gaps in most of Eurasia and parts of North America, making robust assessments for the whole Arctic impossible at present. To fully assess pan-Arctic hydroclimate variability for the last 2 millennia, additional proxy records are required.

Short summary
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.