Science Source

Should coastal planners have concern over where land ice is melting?

States that sea-level rise (SLR) perturbs the Earth’s gravitational and rotational potentials, resulting in strong spatial patterns in sea-level rise (SLR), termed sea-level fingerprints
States that we lack robust forecasting models for future ice changes, which diminishes our ability to use these fingerprints to accurately predict changes
Study authors exploit an advanced mathematical property of adjoint systems and determine the exact gradient of sea-level fingerprints with respect to local variations in the ice thickness of all of the world’s ice drainage systems
Forms a new diagnosis tool—by exhaustively mapping these fingerprint gradients—henceforth referred to as gradient fingerprint mapping (GFM), that readily allows for improved assessments of future coastal inundation or emergence
Demonstrates that for Antarctica and Greenland, changes in the predictions of inundation at major port cities depend on the location of the drainage system.
States as an example that in London, GFM shows local sea-level (LSL) that is significantly affected by changes on the western part of the Greenland Ice Sheet (GrIS), whereas in New York, LSL change predictions are greatly sensitive to changes in the northeastern portions of the GrIS
Applies GFM to 293 major port cities to allow coastal planners to readily calculate LSL change as more reliable predictions of cryospheric mass changes become available