Was pre–twentieth century sea level stable?



Sea level rise (SLR) ranks high on the list of climate change issues because the expected acceleration from the current rate (about 3.1 millimeters per year) poses threats to coastal regions. Tide gauge, salt marsh, and archaeological records, and modeling of glacioisostatic adjustment (GIA) have led to the widely accepted idea that late Holocene (the past ∼2000 years) sea level was stable prior to acceleration beginning around 1850–1900 C.E. For instance, according to the Intergovernmental Panel on Climate Change Fourth Assessment Report, before the last century, sea level had “stabilized” over the past 2000 years, rising at a mean rate of 0–0.2 millimeter per year [Bindoff et al., 2007]. Others maintain that sea level was “nearly stable” over the past few thousand years [Nicholls and Cazenave, 2010], pre–twentieth century rates were “close to zero” [Church et al., 2008], or “stable from at least BC 100 until AD 950” and “stable, or slightly falling” from 1350 until the nineteenth century [Kemp et al., 2011].


Thanks to C. Saenger, J. Briner, E. Thomas, T. Törnqvist, C. Bernhardt, L. Wingard, and two anonymous reviewers for helpful comments. This work was supported by the U.S. Geological Survey Global Change Program.