Portal de Periódicos da CAPES

Eemian interglacial reconstructed from a Greenland folded ice core

2013; Nature Portfolio; Volume: 493; Issue: 7433 Linguagem: Inglês

10.1038/nature11789

1476-4687

Dorthe Dahl‐Jensen, M. R. Albert, Ala Aldahan, Nobuhiko Azuma, D. Balslev-Clausen, M. Baumgartner, Ann-Marie Berggren, Matthias Bigler, Tobias Binder, Thomas Blunier, Jacky Bourgeois, Edward J. Brook, S. L. Buchardt, Christo Buizert, Émilie Capron, J. Chappellaz, Jiwoong Chung, Henrik Clausen, Ivana Cvijanović, Siwan M. Davies, Peter Ditlevsen, O. Eicher, Hubertus Fischer, David Fisher, Louise G. Fleet, Gideon Gfeller, Vasileios Gkinis, Prasad Gogineni, Kumiko Goto‐Azuma, Aslak Grinsted, Hera Guðlaugsdòttir, Mathieu Guillevic, Steffen Bo Hansen, Margareta Hansson, Motohiro Hirabayashi, Seok‐Hwi Hong, Soon-Do Hur, Philippe Huybrechts, Christine S. Hvidberg, Yoshinori Iizuka, Theo M. Jenk, S. J. Johnsen, Tyler R. Jones, Jean Jouzel, Nanna B. Karlsson, Kenji Kawamura, Kaitlin M. Keegan, E. Kettner, Sepp Kipfstuhl, Helle Astrid Kjær, Michelle Koutnik, Takayuki Kuramoto, Peter Köhler, Thomas Laepple, Amaëlle Landais, Peter L. Langen, L. B. Larsen, Daiana Leuenberger, Markus Leuenberger, C. Leuschen, J. Li, V. Lipenkov, Patricia Martinerie, O. J. Maselli, Valérie Masson‐Delmotte, Joseph R. McConnell, Heinrich Miller, O. Mini, Ayaho Miyamoto, M. Montagnat-Rentier, Robert Mulvaney, Raimund Muscheler, Anaïs Orsi, John Paden, Christian Panton, Frank Pattyn, Jean‐Robert Petit, K. Pol, Trevor Popp, Göran Possnert, F. Prié, M. Prokopiou, Aurélien Quiquet, Sune Olander Rasmussen, Dominique Raynaud, Jiangtao Ren, C. Reutenauer, Catherine Ritz, Thomas Röckmann, Julia Rosén, Mauro Rubino, Oleg Rybak, Denis Samyn, Célia Sapart, A. Schilt, A. M. Z. Schmidt, Jakob Schwander, Simon Schüpbach, Inger K Seierstad, J. P. Severinghaus, Simon G. Sheldon, Sebastian B. Simonsen, Jesper Sjolte, Anne Solgaard, Todd Sowers, Peter Sperlich, Hans Christian Steen‐Larsen, Konrad Steffen, J. P. Steffensen, Daniel Steinhage, Thomas F. Stocker, C. Stowasser, A. S. Sturevik, William T. Sturges, A. E. Sveinbjörnsdottír, Anders Svensson, Jean‐Louis Tison, Jun Uetake, Paul Vallelonga, R. S. W. van de Wal, Gerko van der Wel, Bruce H. Vaughn, Bo Vinther, Edwin D. Waddington, Anna Wegner, Ilka Weikusat, J. W. C. White, Frank Wilhelms, Mai Winstrup, Emmanuel Witrant, Eric Wolff, Cunde Xiao, James Zheng,

Climate change and permafrost

Efforts to extract a Greenland ice core with a complete record of the Eemian interglacial (130,000 to 115,000 years ago) have until now been unsuccessful. The response of the Greenland ice sheet to the warmer-than-present climate of the Eemian has thus remained unclear. Here we present the new North Greenland Eemian Ice Drilling (‘NEEM’) ice core and show only a modest ice-sheet response to the strong warming in the early Eemian. We reconstructed the Eemian record from folded ice using globally homogeneous parameters known from dated Greenland and Antarctic ice-core records. On the basis of water stable isotopes, NEEM surface temperatures after the onset of the Eemian (126,000 years ago) peaked at 8 ± 4 degrees Celsius above the mean of the past millennium, followed by a gradual cooling that was probably driven by the decreasing summer insolation. Between 128,000 and 122,000 years ago, the thickness of the northwest Greenland ice sheet decreased by 400 ± 250 metres, reaching surface elevations 122,000 years ago of 130 ± 300 metres lower than the present. Extensive surface melt occurred at the NEEM site during the Eemian, a phenomenon witnessed when melt layers formed again at NEEM during the exceptional heat of July 2012. With additional warming, surface melt might become more common in the future. Reconstruction of the Eemian interglacial from the new NEEM ice core shows that in spite of a climate warmer by eight degrees Celsius in Northern Greenland than that of the past millennium, the ice here was only a few hundred metres lower than its present level. The Greenland ice sheet is losing mass and contributing to ongoing sea level rise, but an incomplete understanding of its changes during the last interglacial 130,000–115,000 years ago, termed the Eemian, have hampered firm predictions. Now an international team has successfully reconstructed the Eemian climate record from the new NEEM ice core. The record shows that in spite of a climate 8 °C warmer than that of the past millennium, the thickness of the ice sheet decreased by only a few hundred metres. In addition, the ice core shows that there was significant surface melt in the north-central parts of the ice sheet during the Eemian, conditions we might soon see again, as demonstrated by melt layers formed at NEEM by the warm temperatures observed over Greenland in July 2012.