My research

Ice Age Sea level

In my research I try to understand how we can use the sea level record to interpret changes in ice volume during the glacial cycles. The idea is to use paleo-climate as a natural laboratory to study the Earth. We have records of past sea level from different sites, but their relationship to an ice-equivalent mean sea level is not trivial. Local sea level deviates from such an ice-equivalent mean due to direct gravitational effects from the changing ice and ocean load as well as the viscoelastic response of the Earth to this load. In my work I model these effects in order to reconcile the available data, make estimates of past ice volume change and get better constraints on the Earth's internal structure.

Longterm Sea level

In addition to these effects related to glacial isostatic adjustment, I am also interested in dynamic topography, which influences the sea level record over longer time scales. Dynamic topography is the surface expression of mantle convection. I use the mantle convection code Aspect to model dynamic topography and investigate how it alters the local sea level estimate. I'm particularly interested in the sea level highstand during the Mid-Pliocene Warm Period, around 3 Ma ago.

Plate tectonics and Geodynamics

I am interested in global plate tectonics and geodynamics. During my master's degree I dealt with projects involving numerical models of the coupled mantle/lithosphere system. I was interested in problems involving plate boundary forces to analyze how and why plates change their motion over time. We used finite rotations that come from magnetic isochrons to reconstruct plate motion over the last few Million years. Subsequently we tried to explain fast accelerations or slow downs with changes in plate boundary forces. In my PhD I've worked on a project looking at the statistical relation between the dynamics of the deep Earth's interior and its surface expression in the form of plumes.

Media articles and blog posts

Selected recent media articles:
 Live Sciene: How will sea levels change with climate change? (2020)
 Vice: Vast Ancient Lake Is Hidden Deep Under Greenland’s Ice, Scientists Discover (2020)
 EOS: An Ice Sheet’s Footprint on Ancient Shorelines (2020)
 Fox News: Past sea-level rise? Scientists find evidence several million years old (2019)
 Science Daily: Evidence for past high-level sea rise (2019)

Earth Institute State of the Planet:
Scientists Have Discovered an Ancient Lake Bed Deep Beneath the Greenland Ice (2020)
Should New York build a storm surge barrier? (2019)
Team deciphers sea-level rise from last time Earth’s CO2 was as high as today (2019)
A world warmer by just 2ºC will be very different from today (2018)
How high can seas rise? On a tropical isle, the answers are not always obvious (2018)

Jacky Austermann
Department of Earth and Environmental Sciences
Columbia University
Lamont-Doherty Earth Observatory

email: jackya [at] ldeo [dot] columbia [dot] edu