A Paleo-perspective on Ocean Heat Exchange: Lessons from the Holocene and Common Era
About Dr. Yair Rosenthal
Dr. Rosenthal received his B.Sc. and M.Sc. from the Hebrew University in Israel and Ph.D. from the MIT/WHOI Joint Program in Oceanography in. He joined Rutgers in 1997, where he is currently distinguished professor with a joint appointment at both the Department of Marine and Coastal Sciences and the Department of Earth and Planetary Sciences. His research focuses on climate change through Earth’s history. Recently he was a co-chief on IODP Expedition 363 to the Indo-Pacific Warm Pool.
About the Seminar
The ocean constitutes the largest heat reservoir in the Earth’s energy budget and thus exerts a major influence on its climate. Instrumental observations show an increase in ocean heat content (OHC) associated with the increase in greenhouse emissions. Here we review proxy records of intermediate water temperatures from sediment cores in the equatorial Pacific and northeastern Atlantic Oceans, spanning 10,000 years beyond the instrumental record. These records suggests that intermediate waters were 1.5-2°C warmer during the Holocene Thermal Maximum than in the last century. Intermediate water masses cooled by 0.9°C from the Medieval Climate Anomaly to the Little Ice Age. The observed changes are significantly larger than the temperature anomalies documented during these time intervals. The implied large perturbations in OHC and Earth’s energy budget may seem at odds with very small radiative forcing anomalies throughout the Holocene and Common Era. We suggest that even very small radiative perturbations can change the latitudinal temperature gradient and strongly affect prevailing atmospheric wind systems and hence air-sea heat exchange. These dynamic processes provide an efficient mechanism to amplify small changes in insolation into relatively large changes in OHC.