Itsuki Suto, Domenico Rio, Jens Matthiessen, Jonaotaro Onodera, Henk Brinkhuis, Matthew Huber, Jan Backman, Nikolai Pedentchouk, Steve Clemens, Masanobu Yamamoto, David McInroy, John W. King, Gerald R. Dickens, Kozo Takahashi, Jérôme Gattacceca, Heiko Pälike, Stefan Schouten, Mahito Watanabe, Jaap S. Sinninghe Damsté, Mark Pagani, R.W. Jordan, Nalân Koç, Noritoshi Suzuki, Martijn Woltering, Tatsuhiko Sakamoto, Michael A. Kaminski, David C. Smith, Frédérique Eynaud, Kristen St. John, Gert-Jan Reichart, Theodore C. Moore, Ruediger Stein, Lucas Joost Lourens, Martin Jakobsson, Kathryn Moran, Brice R. Rea, Thomas M. Cronin, Matt O'Regan, Appy Sluijs, Nahysa C. Martinez, Centre européen de recherche et d'enseignement des géosciences de l'environnement (CEREGE), Institut de Recherche pour le Développement (IRD)-Institut National de la Recherche Agronomique (INRA)-Aix Marseille Université (AMU)-Collège de France (CdF (institution))-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), and Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Collège de France (CdF (institution))-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA)
The Palaeocene/Eocene thermal maximum, ~55 million years ago, was a brief period of widespread, extreme climatic warming1, 2, 3, that was associated with massive atmospheric greenhouse gas input4. Although aspects of the resulting environmental changes are well documented at low latitudes, no data were available to quantify simultaneous changes in the Arctic region. Here we identify the Palaeocene/Eocene thermal maximum in a marine sedimentary sequence obtained during the Arctic Coring Expedition5. We show that sea surface temperatures near the North Pole increased from ~18 °C to over 23 °C during this event. Such warm values imply the absence of ice and thus exclude the influence of ice-albedo feedbacks on this Arctic warming. At the same time, sea level rose while anoxic and euxinic conditions developed in the ocean's bottom waters and photic zone, respectively. Increasing temperature and sea level match expectations based on palaeoclimate model simulations6, but the absolute polar temperatures that we derive before, during and after the event are more than 10 °C warmer than those model-predicted. This suggests that higher-than-modern greenhouse gas concentrations must have operated in conjunction with other feedback mechanisms—perhaps polar stratospheric clouds7 or hurricane-induced ocean mixing8—to amplify early Palaeogene polar temperatures.