Recent global sea level acceleration started over 200 years ago?

TLDR

Long time constants in oceanic heat content and increased ice‑sheet melting suggest that recent IPCC sea‑level rise estimates may be too low. The study reconstructs global sea level since 1700 from tide gauge records to analyze its acceleration over the past 300 years. Using these records, the authors examine the evolution of global sea‑level acceleration. Observations indicate an acceleration of about 0.01 mm yr⁻² beginning in the late 18th century, with 6 cm rise in the 19th century, 19 cm in the 20th, 60‑year quasi‑periodic fluctuations, and a projected 34 cm rise over the 21st century if current conditions continue.

Abstract

We present a reconstruction of global sea level (GSL) since 1700 calculated from tide gauge records and analyse the evolution of global sea level acceleration during the past 300 years. We provide observational evidence that sea level acceleration up to the present has been about 0.01 mm/yr 2 and appears to have started at the end of the 18th century. Sea level rose by 6 cm during the 19th century and 19 cm in the 20th century. Superimposed on the long‐term acceleration are quasi‐periodic fluctuations with a period of about 60 years. If the conditions that established the acceleration continue, then sea level will rise 34 cm over the 21st century. Long time constants in oceanic heat content and increased ice sheet melting imply that the latest Intergovernmental Panel on Climate Change (IPCC) estimates of sea level are probably too low.