title: Deglacial temperature history of West Antarctica.
abstract: The most recent glacial to interglacial transition constitutes a remarkable natural experiment for learning how Earth's climate responds to various forcings, including a rise in atmospheric CO2This transition has left a direct thermal remnant in the polar ice sheets, where the exceptional purity and continual accumulation of ice permit analyses not possible in other settings. For Antarctica, the deglacial warming has previously been constrained only by the water isotopic composition in ice cores, without an absolute thermometric assessment of the isotopes' sensitivity to temperature. To overcome this limitation, we measured temperatures in a deep borehole and analyzed them together with ice-core data to reconstruct the surface temperature history of West Antarctica. The deglacial warming was [Formula: see text]C, approximately two to three times the global average, in agreement with theoretical expectations for Antarctic amplification of planetary temperature changes. Consistent with evidence from glacier retreat in Southern Hemisphere mountain ranges, the Antarctic warming was mostly completed by 15 kyBP, several millennia earlier than in the Northern Hemisphere. These results constrain the role of variable oceanic heat transport between hemispheres during deglaciation and quantitatively bound the direct influence of global climate forcings on Antarctic temperature. Although climate models perform well on average in this context, some recent syntheses of deglacial climate history have underestimated Antarctic warming and the models with lowest sensitivity can be discounted.
authors.affiliation: Department of Geography, University of California, Berkeley, CA 94720; kcuffey@berkeley.edu.
authors.forename: Kurt M
authors.identifier: 0000-0001-9314-2996
authors.initials: KM
authors.lastname: Cuffey
authors.affiliation: Geosciences and Environmental Change Science Center, United States Geological Survey, Lakewood, CO 80225.
authors.forename: Gary D
authors.initials: GD
authors.lastname: Clow
authors.affiliation: Department of Earth and Space Sciences, University of Washington, Seattle, WA 98195.
authors.forename: Eric J
authors.initials: EJ
authors.lastname: Steig
authors.affiliation: College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, OR 97331.
authors.forename: Christo
authors.initials: C
authors.lastname: Buizert
authors.affiliation: Department of Earth and Space Sciences, University of Washington, Seattle, WA 98195.
authors.forename: T J
authors.initials: TJ
authors.lastname: Fudge
authors.affiliation: Department of Earth and Space Sciences, University of Washington, Seattle, WA 98195.
authors.forename: Michelle
authors.initials: M
authors.lastname: Koutnik
authors.affiliation: Department of Earth and Space Sciences, University of Washington, Seattle, WA 98195.
authors.forename: Edwin D
authors.initials: ED
authors.lastname: Waddington
authors.affiliation: Department of Geosciences, The Pennsylvania State University, University Park, PA 16802.
authors.forename: Richard B
authors.initials: RB
authors.lastname: Alley
authors.affiliation: Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA 92093.
authors.forename: Jeffrey P
authors.identifier: 0000-0001-8883-3119
authors.initials: JP
authors.lastname: Severinghaus
keywords: Antarctica; climate; glaciology; paleoclimate; temperature