Deglacial temperature history of West Antarctica

TitleDeglacial temperature history of West Antarctica
Publication TypeJournal Article
Year of Publication2016
AuthorsCuffey K.M, Clow G.D, Steig E.J, Buizert C, Fudge T.J, Koutnik M., Waddington E.D, Alley R.B, Severinghaus JP
JournalProceedings of the National Academy of Sciences of the United States of America
Date Published2016/12
Type of ArticleArticle
ISBN Number0027-8424
Accession NumberWOS:000389696700043
Keywordsantarctica; atmospheric co2; climate; Climate sensitivity; core wd2014 chronology; glaciology; heinrich stadial 1; ice-sheet; last glacial maximum; model; new-zealand; paleoclimate; polar firn; southern-ocean; temperature

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 CO2. This 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 11.3 +/- 1.8 degrees 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.

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