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SUMMARY:Looking at Last Interglacial Sea Level records through a solid Ear
 th lens - Jacky Austermann\, Bullard Labs\, University of Cambridge
DTSTART:20161108T120000Z
DTEND:20161108T130000Z
UID:TALK68965@talks.cam.ac.uk
CONTACT:John Maclennan
DESCRIPTION:To gain insight into the question of ice sheet stability and s
 ea level change in the face of global warming\, scientists have turned to 
 studying warm periods in the geologic past. The Last Interglacial (LIG)\, 
 ~125 ka\, has been of particular interest in this regard since atmospheric
  CO2 concentrations during the LIG were comparable to pre-industrial value
 s and temperatures were consistent with simulations involving 1-2º global
  warming.\n\nEstimating peak global mean sea level\, or equivalently minim
 um ice volumes\, during the Last Interglacial requires that the elevation 
 of local sea level records be corrected for processes that distort local s
 ea level relative to the global average. One such process is glacial isost
 atic adjustment (GIA)\, which is the change in topography that occurs due 
 to the loading (or unloading) of the Earth with ice sheets and water. Stud
 ies that have taken this process into account conclude that LIG global mea
 n sea level peaked 6-9m above present-levels.\n\nIn this talk I will addre
 ss previously unrecognized uncertainties in the GIA correction that stem f
 rom our incomplete knowledge of the temporal evolution of ice sheets prior
  to and during the LIG. I will further talk about the role of dynamic topo
 graphy in deforming and biasing the LIG sea level record globally. Dynamic
  topography is the topography that is supported by viscous flow and buoyan
 cy variations in the Earth’s mantle and lithosphere. To date\, this glob
 al scale process has been ignored in sea level studies of Pleistocene inte
 rglacials\, including the LIG\, under the assumption that the signal would
  be negligible. I will show that modeled deflections span several meters\,
  that they are significantly correlated with observed sea level highstands
  and that they are consistent with construction and preservation attribute
 s across different sea level indicator types.\n\nReferences:\n\nCreveling 
 et al.\, 2015\, Revisiting tectonic corrections applied to Pleistocene sea
 -level highstands\, Quaternary Science Reviews 111\, 72-80.\n\nDutton et a
 l.\, 2015\, Sea-level rise due to polar ice-sheet mass loss during past wa
 rm periods. Science 349\, 153.\n\nRovere et al.\, 2016\, The analysis of L
 ast Interglacial (MIS 5e) relative sea-level indicators: Reconstructing se
 a-level in a warmer world. Earth-Science Reviews 159\, 404-427.
LOCATION:Tilley Lecture Theatre\, Department of Earth Sciences
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