Correcting sea level rise projections by vertical land motions along the South American Pacific Coast

Accurate sea-level rise projections require accounting for vertical land motion, which can significantly amplify or offset relative sea-level trends, especially in tectonically active regions. The South American Pacific Coast exhibits strong spatial vertical land motion variability due to subduction processes and major earthquakes. We correct sea level rise projections under +4K global warming scenario using three datasets: satellite altimetry and tide gauge single difference from 1993 to 2020, InSAR-derived deformation 2020–2025, and Couple Model Intercomparison Project phase 6 vertical land motion outputs, to compare how point-based and spatially continuous vertical land motion estimates may differ/coincide and evaluate their impact on sea-level rise corrections. Results show different vertical land motion rates for the three datasets, where the highest values, obtained by differencing between satellite and tide gauge stations, vary from -1.64 mm/yr (subsidence in Manta, Ecuador) to +6.75 mm/yr (uplift in Talcahuano, Chile), comparable to the global mean sea-level rise. Including these corrections alters 2100 regional sea level rise projections by up to ±0.5 m, with results of the Coupled Model Intercomparison Project phase 6 often overestimating uplift compared to InSAR in spatial variability.