The causes of sea-level rise since 1900

Global-mean sea level has been rising unsteadily since 1900, and the underlying causes are still poorly understood. Here we present a probabilistic framework to reconstruct and budget sea level with independent observations considering their inherent uncertainties. We find that the sum of thermal expansion, ice-mass loss and terrestrial water storage changes is consistent with the trends and multi-decadal variability in observed sea level on both global and basin scales, which we reconstruct from tide-gauge records. Glacier-dominated cryospheric mass loss has caused twice as much sea-level rise as thermal expansion since 1900. Ice mass changes also well explain the high rates typically seen in global sea-level reconstructions during the 1930s, while a sharp increase in water impoundment by man-made reservoirs has been the dominant contributor to lower-than-average rates during the 1970s. The acceleration over the last decades is caused by both thermal expansion and increased Greenland mass loss. No additional large-scale deep ocean warming or Antarctic Ice Sheet mass loss are needed to explain 20th-century changes global-mean sea level. This assessment reconciles the magnitude of observed global-mean sea-level rise since 1900 with the sum of underlying processes.