Mean global ocean temperatures during the last glacial transition

• Published in: Nature
• Main Authors: Bereiter, Bernhard, Shackleton, Sarah, Baggenstos, Daniel, Kawamura, Kenji, Severinghaus, Jeff
• Format: Article in Journal/Newspaper
• Language: English
• Published: Springer Nature 2018
• Subjects: Antarc*; Antarctic
• Online Access: https://doi.org/10.1038/nature25152

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 CO 2 , 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.