Abstract
Ocean dynamic sea level (DSL) change is a key driver of relative sea
level (RSL) change. Projections of DSL change are generally obtained
from simulations using atmosphere-ocean general circulation models
(GCMs). Here, we develop a two-layer climate emulator to interpolate
between emission scenarios simulated with GCMs and extend projections
beyond the time horizon of available simulations. This emulator captures
the evolution of DSL changes in corresponding GCMs, especially over
middle and low latitudes. Compared with an emulator using univariate
pattern scaling, the two-layer emulator more accurately reflects GCM
behavior and captures non-linearities and non-stationarity in the
relationship between DSL and global-mean warming. Using the emulator, we
develop a probabilistic ensemble of DSL projections through 2300 for
four scenarios: Representative Concentration Pathway (RCP) 2.6, RCP4.5,
RCP8.5, and Shared Socioeconomic Pathway (SSP) 3-7.0. The magnitude and
uncertainty of projected DSL changes decrease from the high- to the low-
emission scenarios, indicating a reduced DSL rise hazard in low- and
moderate- emission scenarios (RCP2.6 and RCP4.5) compared to the
high-emission scenarios (SSP3-7.0 and RCP8.5).