The latter study denotes that the largest difference occurs during 1940–70. (2016) find that the sum of contributors, based on climate model results, is lower than the observed rise in global mean sea level. Over the twentieth century, Gregory et al. This large spread in reconstructed sea level trends hinders the attribution of observed sea level changes to the individual processes. As an example, the mean estimates of sea level rise from 1900 to 1990 vary between 1.1 and 2.0 mm yr −1 ( Church and White 2011 Jevrejeva et al. These methodological differences, together with the inclusion or exclusion of specific tide-gauge stations, result in a large spread in published sea level rise estimates. A wide variety of methods has been used to reconstruct global sea level changes from individual tide-gauge records. These problems pose a challenge for reconstructions of global and regional sea level rise. Global sea level reconstructions before the satellite altimetry era mostly depend on tide-gauge records, which are sparsely sampled over the globe, contain data gaps, and are affected by vertical land motion (VLM). Since 1993, both reconstructed sea level and the sum of contributors show good agreement with altimetry estimates. Over the same period, the reconstruction shows a positive acceleration of 0.07 ± 0.02 mm yr −2, which is also in agreement with the sum of contributors, which shows an acceleration of 0.07 ± 0.01 mm yr −2. The global-mean sea level reconstruction shows a trend of 1.5 ± 0.2 mm yr −1 over 1958–2014 (1 σ), compared to 1.3 ± 0.1 mm yr −1 for the sum of contributors. The sparsely sampled South Atlantic Ocean forms an exception. For the first time, it is shown that for most basins the reconstructed sea level trend and acceleration can be explained by the sum of contributors, as well as a large part of the decadal variability. Tide-gauge records are combined with observations of vertical land motion, independent estimates of ice-mass loss, terrestrial water storage, and barotropic atmospheric forcing in a self-consistent framework to reconstruct sea level changes on basin and global scales, which are compared to the estimated sum of contributing processes. ![]() To assess these open questions, reconstructed sea level and the role of the contributors are investigated on a local, basin, and global scale. Possible causes for this spread are, among others, vertical land motion at tide-gauge locations and the sparse sampling of the spatially variable ocean. Different sea level reconstructions show a spread in sea level rise over the last six decades and it is not yet certain whether the sum of contributors explains the reconstructed rise.
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