1. Antarctic ice sheet sensitivity to atmospheric CO2 variations in the early to mid-Miocene
- Author
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Richard Levy, David Harwood, Fabio Florindo, Francesca Sangiorgi, Robert Tripati, Hilmar von Eynatten, Edward Gasson, Gerhard Kuhn, Aradhna Tripati, Robert DeConto, Christopher Fielding, Brad Field, Nicholas Golledge, Robert McKay, Timothy Naish, Matthew Olney, David Pollard, Stefan Schouten, Franco Talarico, Sophie Warny, Veronica Willmott, Gary Acton, Kurt Panter, Timothy Paulsen, Marco Taviani, SMS Science Team: Rosemary Askin, Clifford Atkins, Kari Bassett, Alan Beu, Brian Blackstone, Gregory Browne, Alessandro Ceregato, Rosemary Cody, Gianluca Cornamusini, Sveva Corrado, Paola Del Carlo, Gianfranco Di Vincenzo, Gavin Dunbar, Candice Falk, Tracy Frank, Giovanna Giorgetti, Thomas Grelle, Zi Gui, David Handwerger, Michael Hannah, David M Harwood, Dan Hauptvogel, Travis Hayden, Stuart Henrys, Stefan Hoffmann, Francesco Iacoviello, Scott Ishman, Richard Jarrard, Katherine Johnson, Luigi Jovane, Shelley Judge, Michelle Kominz, Matthew Konfirst, Lawrence Krissek, Laura Lacy, Paola Maffioli, Diana Magens, Maria C Marcano, Cristina Millan, Barbara Mohr, Paola Montone, Samuel Mukasa, Frank Niessen, Christian Ohneiser, Mathew Olney, Sandra Passchier, Molly Patterson, Stephen Pekar, Simona Pierdominici, Ian Raine, Joshua Reed, Lucia Reichelt, Christina Riesselman, Sergio Rocchi, Leonardo Sagnotti, Sonia Sandroni, Douglas Schmitt, Marvin Speece, Bryan Storey, Eleonora Strada, Eva Tuzzi, Kenneth Verosub, Gary Wilson, Terry Wilson, Thomas Wonik, Massimiliano Zattin, Levy, Richard, Harwood, David, Florindo, Fabio, Sangiorgi, Francesca, Tripati, Robert, von Eynatten, Hilmar, Gasson, Edward, Kuhn, Gerhard, Tripati, Aradhna, Deconto, Robert, Fielding, Christopher, Field, Brad, Golledge, Nichola, Mckay, Robert, Naish, Timothy, Olney, Matthew, Pollard, David, Schouten, Stefan, Talarico, Franco, Warny, Sophie, Willmott, Veronica, Acton, Gary, Panter, Kurt, Paulsen, Timothy, Taviani, Marco, Corrado, Sveva, and Science Team, Sms
- Subjects
geography ,geography.geographical_feature_category ,Multidisciplinary ,010504 meteorology & atmospheric sciences ,Antarctica ,Climate Optimum ,Ice sheet ,Miocene ,Ross Sea ,Ice stream ,Antarctic ice sheet ,Antarctic sea ice ,010502 geochemistry & geophysics ,01 natural sciences ,ice sheet ,Ice-sheet model ,Ice core ,13. Climate action ,Physical Sciences ,Sea ice ,Cryosphere ,Physical geography ,0105 earth and related environmental sciences - Abstract
Geological records from the Antarctic margin offer direct evidence of environmental variability at high southern latitudes and provide insight regarding ice sheet sensitivity to past climate change. The early to mid-Miocene (23-14 Mya) is a compelling interval to study as global temperatures and atmospheric CO2 concentrations were similar to those projected for coming centuries. Importantly, this time interval includes the Miocene Climatic Optimum, a period of global warmth during which average surface temperatures were 3-4 degrees C higher than today. Miocene sediments in the ANDRILL-2A drill core from the Western Ross Sea, Antarctica, indicate that the Antarctic ice sheet (AIS) was highly variable through this key time interval. A multiproxy dataset derived from the core identifies four distinct environmental motifs based on changes in sedimentary facies, fossil assemblages, geochemistry, and paleotemperature. Four major dis-conformities in the drill core coincide with regional seismic discontinuities and reflect transient expansion of grounded ice across the Ross Sea. They correlate with major positive shifts in benthic oxygen isotope records and generally coincide with intervals when atmospheric CO2 concentrations were at or below preindustrial levels (similar to 280 ppm). Five intervals reflect ice sheet minima and air temperatures warm enough for substantial ice mass loss during episodes of high (similar to 500 ppm) atmospheric CO2. These new drill core data and associated ice sheet modeling experiments indicate that polar climate and the AIS were highly sensitive to relatively small changes in atmospheric CO2 during the early to mid-Miocene.
- Published
- 2016
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