  The modern era of scientific global-mean sea-level rise (SLR) projections
began in the early 1980s. In subsequent decades, understanding of driving
processes has improved, and new methodologies have been developed. Nonetheless,
despite more than 70 studies, future SLR remains deeply uncertain. To
facilitate understanding of the historical development of SLR projections and
contextualize current projections, we have compiled a comprehensive database of
21st century global SLR projections. Although central estimates of 21st century
global-mean SLR have been relatively consistent, the range of projected SLR has
varied greatly over time. Among studies providing multiple estimates, the range
of upper projections shrank from 1.3 to 1.8 m during the 1980s to 0.6 to 0.9 m
in 2007, before expanding again to 0.5 to 2.5 m since 2013. Upper projections
of SLR from individual studies are generally higher than upper projections from
the Intergovernmental Panel on Climate Change, potentially due to differing
percentile bounds, or a pre-disposition of consensus-based approaches toward
relatively conservative outcomes.
