Temperature-driven global sea-level variability in the Common Era

Abstract

We assess the relationship between temperature and global sea-level (GSL) variability over the Common Era through a statistical metaanalysis of proxy relative sea-level reconstructions and tide-gauge data. GSL rose at 0.1 +/- 0.1 mm/y (2 sigma) over 0-700 CE. A GSL fall of 0.2 +/- 0.2 mm/y over 1000-1400 CE is associated with similar to 0.2 degrees C global mean cooling. A significant GSL acceleration began in the 19th century and yielded a 20th century rise that is extremely likely (probability P >= 0.95) faster than during any of the previous 27 centuries. A semiempirical model calibrated against the GSL reconstruction indicates that, in the absence of anthropogenic climate change, it is extremely likely (P = 0.95) that 20th century GSL would have risen by less than 51% of the observed 13.8 +/- 1.5 cm. The new semiempirical model largely reconciles previous differences between semiempirical 21st century GSL projections and the process model-based projections summarized in the Intergovernmental Panel on Climate Change's Fifth Assessment Report.