Mean global ocean temperatures during the last glacial transition

Little is known about the ocean temperature’s long-term response to climate perturbations owing to limited observations and a lack of robust reconstructions. Although most of the anthropogenic heat added to the climate system has been taken up by the ocean up until now, its role in a century and bey...

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Bibliographic Details
Main Authors: Bereiter, Bernhard, Shackleton, Sarah, Baggenstos, Daniel, Kawamura, Kenji, Severinghaus, Jeff
Format: Text
Language:English
Published: Macmillan Journals Ltd. 2018
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Online Access:https://dx.doi.org/10.7892/boris.112604
https://boris.unibe.ch/112604/
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Summary:Little is known about the ocean temperature’s long-term response to climate perturbations owing to limited observations and a lack of robust reconstructions. Although most of the anthropogenic heat added to the climate system has been taken up by the ocean up until now, its role in a century and beyond is uncertain. Here, using noble gases trapped in ice cores, we show that the mean global ocean temperature increased by 2.57 ± 0.24 degrees Celsius over the last glacial transition (20,000 to 10,000 years ago). Our reconstruction provides unprecedented precision and temporal resolution for the integrated global ocean, in contrast to the depth-, region-, organism- and season-specific estimates provided by other methods. We find that the mean global ocean temperature is closely correlated with Antarctic temperature and has no lead or lag with atmospheric CO₂, thereby confirming the important role of Southern Hemisphere climate in global climate trends. We also reveal an enigmatic 700-year warming during the early Younger Dryas period (about 12,000 years ago) that surpasses estimates of modern ocean heat uptake.