Comment on the subsidence adjustment applied to the Kemp et al. proxy of North Carolina relative sea level

Abstract

Kemp et al. ( 1) presented a new salt-marsh proxy record of relative sea level (RSL) from North Carolina (NCRSL). The salt marsh is slowly subsiding as a result of glacial isostatic adjustment (GIA), and the NCRSL record needs to be adjusted to remove this vertical land movement from the sea level record. Kemp et al. ( 1) corrected for a constant subsidence rate of approximately 1 mm/y. This is a “geologic” estimate based on sea level index points, which are determined from linear fits to data from other North American RSL proxy records. Thus, the geologic method implicitly assumes that the entire trend is a result of subsidence and leaves no room for any millennial-scale climate-driven changes in sea level. It is therefore not ..