Uncertainty of the 20th century sea-level rise due to vertical land motion errors

Assessing the vertical land motion (VLM) at tide gauges (TG) is crucial to understanding global and regional mean sea-level changes (SLC) over the last century. However, estimating VLM with accuracy better than a few tenths of a millimeter per year is not a trivial undertaking and many factors, including the reference frame uncertainty, must be considered. Using a novel reconstruction approach and updated geodetic VLM corrections, we found the terrestrial reference frame and the estimated VLM uncertainty may contribute to the global SLC rate error by View the MathML source. In addition, a spurious global SLC acceleration may be introduced up to View the MathML source. Regional SLC rate and acceleration errors may be inflated by a factor 3 compared to the global. The difference of VLM from two independent Glacio-Isostatic Adjustment models introduces global SLC rate and acceleration biases at the level of View the MathML source and View the MathML source, increasing up to 0.5 mm yr−1 and View the MathML source for the regional SLC. Errors in VLM corrections need to be budgeted when considering past and future SLC scenarios.