Jacqueline Austermann is a leading figure in efforts to bring insights from solid Earth geophysics and tectonophysics to bear on important, outstanding problems in paleoclimate research.
Her work as an M.Sc. student at Ludwig-Maximilians-Universität München identified the tectonic driving forces behind both the enigmatic change in Pacific plate motion at 6 Ma and the slowdown in Arabia–Eurasia plate convergence since 5 Ma. With this “solid” training in hand, her initial Ph.D. research at Harvard University addressed a long-standing debate within the ice age climate literature by demonstrating that estimates of the total excess ice volume at the Last Glacial Maximum (LGM) based on the Barbados coral record were biased low by neglecting the impact on crustal dynamics of the high-viscosity upper mantle slab below the site associated with convergence of the South American and Caribbean plates. Moreover, her revised estimate (~130 meters in units of equivalent global mean sea level rise) has defined an important “missing ice mass” problem because reconstructions of LGM ice volume based on near-field geological records suggest a value of approximately 100 meters. Her next two studies involved modeling of vertical deflections of the crust associated with mantle convection (dynamic topography). First, she demonstrated that bedrock topography in the Wilkes Basin sector of the East Antarctic was approximately 100–200 meters lower during the mid-Pliocene Warm Period (MPWP; ~3 Ma) than at present day due to dynamic uplift, and that ice sheet modeling based on this reconstructed topography was capable of reconciling a local geological record suggestive of instability in the ice sector during the MPWP. Next, she turned to the Last Interglacial (LIG; ~120 ka), the last time the Earth experienced a protracted warming. Jacky showed that a dynamic topography signal was detectable at a statistically significant level in the coral elevation record and that uncertainties in our current estimates of LIG sea level, and associated ice sheet stability, were being significantly underestimated.
Jacky’s contributions have continued unabated through her postdoctoral years at Cambridge University and in her current faculty position at Columbia University. As a notable example, her most recent publication has argued—on the basis of a speleothem record from the Mediterranean corrected for glacial isostatic adjustment and dynamic topography—that global mean sea level during the MPWP peaked approximately 17 meters above present day, implying major instability of polar ice sheets.
Jacky Austermann is a remarkably creative young scientist whose scholarly work provides an outstanding example of the power of interdisciplinary paleoclimate research when practiced through the prism of solid Earth geophysics. She is, in addition, a talented educator and unselfish collaborator who has served as an important mentor to graduate students and PDFs at Harvard, Cambridge, and Columbia. The Jason Morgan Early Career Award of the Tectonophysics section aptly recognizes all of these impressive contributions.
—Jerry X. Mitrovica, Harvard University, Cambridge, Mass.
Contemporary crustal uplift and relative sea level (RSL) change in Greenland is caused by the response of the solid Earth to ongoing and historical...