A geophysical approach to reconstructing past global mean sea levels using highly resolved sea-level records

Abstract

Sea level is an excellent proxy for past climate change as it represents the combined impact of changing temperatures and ice volumes through time. Reconstructing a record of global ice volume change is complex as the growth and loss of high volume ice sheets results in a spatially varying pattern of sea-level change. This is known as glacial isostatic adjustment (GIA) and means that all past sea-level indicators are effectively relative sea level (RSL) indicators. Each indicator is relative to a particular position on the Earth’s crust and requires a GIA correction to reconstruct global mean sea level (GMSL).
Generating a GIA correction requires an appropriate ice volume and distribution history. As no field-constrained global ice history exists beyond the last glacial maximum we create five different global ice-loading histories to investigate a range of potential ice volume and dispersal scenarios through the last interglacial.
Within this thesis we develop a methodology for inclusion of coral taxon depth-habitat relationships in the uncertainties associated with fossil coral reconstructed relative sea levels. We test our ice histories against the coral dataset, and find the best matches to the coral dataset come from ice histories that contain a longer interglacial and / or reduced ice volume through the interglacial than is currently found in many continuous records of sea level.
We model the GIA response of the Hanish and Camarinal Sills, and Rosh Hanikra on the Israeli coast to determine how two continuous RSL curves, for the Red Sea and Gibraltar respectively, and the temporally discrete RSL indicators relate to GMSL. Our analysis reveals sensitivities that may be used to constrain the evolution of a past Eurasian ice sheet.

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ORCID for Eelco Rohling: orcid.org/0000-0001-5349-2158

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