Session: Invited talks
Author: Eelco J. Rohling / email@example.com / Research School of Earth Sciences, The Australian National University
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.