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ΔH - The change in ice thickness at a particular point.

dS/dH - The rate of change in local sea level at the chosen city due to ice thickness change at this point.

dS/dH · ΔH - The change in local sea level at the chosen city due to ice thickness change at this point.


Primary Controls


*One of a few geodynamical model solutions that helps to reconcile the observed polar motion.



In this simulation, we show the average speed of Earth’s spin axis—called polar motion—driven by several geophysical sources during two time periods: 1900-2000 and 2003-2015. Data rendered here are results from two papers published by ISSM team at NASA’s JPL, Caltech:

NOTE: Signals are highly exaggerated for the sake of visualization.

Theoretical basis

Redistribution of mass on Earth’s surface (e.g., ice melting, sea-level rise) or within its interior (e.g., glacial rebound, mantle convection) perturbs Earth’s inertia tensor, and hence polar motion. The methods to compute polar motion induced by glacial isostatic adjustment, environmental processes, and mantle convection are detailed in the Supplementary Materials of Adhikari et al. (2018).

Datasets Used in the Simulation

For the period 2003-2015, we rely on GRACE measurements of continental mass changes and complementary model-based solutions—following the methods of Adhikari et al. (2016)—for associated ocean mass redistribution.

For the period 1900-2000, we compute glacial rebound and mantle convection signals using the methods of Caron et al. (2018) and Steinberger et al. (2017), respectively. We assemble models of Earth’s mass transport from various sources, for example, Kjeldsen et al. (2015) for Greenland Ice Sheet, Marzeion et al. (2015) for global glaciers and ice caps, Chao et al. (2008) for dams/reservoirs water impoundment, and Wada et al. (2012) for groundwater depletion.

How to Run the Simulation

In the Controls pane (click LET'S GO), choose a time series from the select menu, then select one or more contributors to display.



If you have any questions or feedback, please send us an email.

Shift Direction

Shift Rate

data marker
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