Subtropical Arctic Ocean temperatures during the Palaeocene/Eocene thermal maximum

• Published in: Nature
• Main Authors: Sluijs, Appy, Schouten, Stefan, Pagani, Mark, Woltering, Martijn, Brinkhuis, Henk, Damsté, Jaap S. Sinninghe, Dickens, Gerald R., Huber, Matthew, Reichart, Gert-Jan, Stein, Ruediger, Matthiessen, Jens, Lourens, Lucas J., Pedentchouk, Nikolai, Backman, Jan, Moran, Kathryn, Clemens, Steve, Cronin, Thomas, Eynaud, Frédérique, Gattacceca, Jérôme, Jakobsson, Martin, Jordan, Ric, Kaminski, Michael, King, John, Koc, Nalân, Martinez, Nahysa C., McInroy, David, Moore, Jr, Theodore C., O'Regan, Matthew, Onodera, Jonaotaro, Pälike, Heiko, Rea, Brice, Rio, Domenico, Sakamoto, Tatsuhiko, Smith, David C., St John, Kristen E. K., Suto, Itsuki, Suzuki, Noritoshi, Takahashi, Kozo, Watanabe, Mahito, Yamamoto, Masanobu
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: NPG 2006
• Subjects: GC Oceanography; QE Geology; Arctic; Arctic Ocean; North Pole; albedo
• Online Access: https://orca.cardiff.ac.uk/id/eprint/10755/; https://doi.org/10.1038/nature04668

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.