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Palaeoclimate Sensitivity, Sea Level, And Ice Volume: How Well Do We Understand Albedo Changes Through Deglaciations?

Event Type: 
Event Date: 
02 May 2018
ASE 3D Viz Laboratory Room (N2-B1c-16c)
Eelco J. Rohling
About the speaker: 

Professor Eelco J. Rohling is based at the Research School of Earth Sciences, The Australian National University, Canberra (since 2013), and secondarily affiliated with the University of Southampton, National Oceanography Centre Southampton, UK (since 1994).

His research focuses on ocean and climate change with emphasis on sea level, climate sensitivity, and past episodes of enhanced carbon burial. Eelco obtained his PhD in 1991 from the University of Utrecht, The Netherlands, and did post-doctoral research at both Utrecht, and the Woods Hole Oceanographic Institution, Mass. USA (1991-1994). He joined the academic faculty staff in the University of Southampton in 1994. Eelco has been awarded a Fellowship of the Royal Netherlands Academy of Arts and Science (2008), a UK Royal Society Wolfson Research Merit Award (2011), an Australian Laureate Fellowship (2013), and a Fellowship of the American Geophysical Union (2017). 

Eelco has been vice-chairman and chairman of the 26-nation International Marine Global Changes Study programme (2003-2008), and vice-president Palaeoclimatology at the European Geosciences Union (2000-2006). He has been associate editor at 4 major journals, and editor of both Paleoceanography (2006-2009) and Reviews of Geophysics (2010-today). He has published ~190 peer-reviewed contributions, and his public science book “The Oceans: a Deep History” has been released in December 2017 by Princeton University Press.

About the event: 

I will go through a method of palaeoclimate sensitivity reconstruction, and will highlight key assumptions. These are currently key targets for several teams aiming to capture potential state dependence of palaeoclimate sensitivity. Such work focuses on deglaciations, to see if and how climate sensitivity changed between glacial and interglacial states. But how do we assess changes in the second major slow feedback after carbon-cycle feedbacks, namely the ice-volume albedo feedback? We need well-dated, and precise sea-level reconstructions for that. For Termination I, the last deglaciation, corals and other coastal landforms have been used to make very detailed sea-level record that are well dated. But do these sufficiently represent the uncertainties? For older terminations, continuous sea-level records (e.g., Red Sea, Mediterranean Sea) offer better control, but not the absolute age control – so detailed frameworks are needed to establish both relative and absolute chronological comparisons with other key climate parameters. These introduce their own level of uncertainty. I will go through an array of issues and solutions that are being investigated. Termination II now emerges as the most promising interval of time for palaeoclimate sensitivity assessment: its sea-level history is simpler (essentially monotonic) and better understood than that for Termination II – in part this is because there is less short-term “noise” that complicates temporal comparisons than in Termination I. For other Terminations, we’re still a ways off, further than we might like, but the problem can be resolved.