Differences between the last two glacial maxima and implications for ice-sheet, δ18O, and sea-level reconstructions. (15th November 2017)

• Record Type: Journal Article
• Authors: Rohling, Eelco J.; Hibbert, Fiona D.; Williams, Felicity H.; Grant, Katharine M.; Marino, Gianluca; Foster, Gavin L.; Hennekam, Rick; de Lange, Gert J.; Roberts, Andrew P.; Yu, Jimin; Webster, Jody M.; Yokoyama, Yusuke
• Is Part Of: Quaternary science reviews. Volume 176(2017)
• Page Start: 1
• Page End: 28
• Publication Date: 2017-11-15
• Subjects: Last Glacial Maximum -- Penultimate Glacial Maximum -- Sea level -- Ice volume -- δ18O -- Arctic ice shelf -- Last Interglacial -- Glacioisostatic adjustment; Geology, Stratigraphic -- Quaternary -- Periodicals; Stratigraphie -- Quaternaire -- Périodiques; 551.79
• DOI: 10.1016/j.quascirev.2017.09.009
• Languages: English
• ISSNs: 0277-3791

Abstract

Abstract: Studies of past glacial cycles yield critical information about climate and sea-level (ice-volume) variability, including the sensitivity of climate to radiative change, and impacts of crustal rebound on sea-level reconstructions for past interglacials. Here we identify significant differences between the last and penultimate glacial maxima (LGM and PGM) in terms of global volume and distribution of land ice, despite similar temperatures and radiative forcing. Our analysis challenges conventional views of relationships between global ice volume, sea level, seawater oxygen isotope values, and deep-sea temperature, and supports the potential presence of large floating Arctic ice shelves during the PGM. The existence of different glacial 'modes' calls for focussed research on the complex processes behind ice-age development. We present a glacioisostatic assessment to demonstrate how a different PGM ice-sheet configuration might affect sea-level estimates for the last interglacial. Results suggest that this may alter existing last interglacial sea-level estimates, which often use an LGM-like ice configuration, by several metres (likely upward). Highlights: We find differences between the last and penultimate glacial maxima (LGM and PGM). Volume and distribution of ice differ, but temperatures and forcing are similar. Results revise relations between ice volume, sea level, O isotopes, and deep-sea T. Results support potential presence of large floating Arctic ice shelves. Last interglacial sea-level estimates are affected by several metres.