Lower Bounds to Future Sea-Level Rise

Abstract

Many recent papers claim that the climate model-based projections made until the Fourth Assessment Report (AR4) of the Intergovernmental Panel on Climate Change (IPCC) yielding a 21st century rise spanning nearly 20–60 cm are likely to underestimate sea-level change in response to rapid climatic variations. These authors project the sea-level rise of 2100 and beyond with semi-empirical methods coupled to a simple climate model finding that sea level is predicted to rise by at least ∼ 80 cm at the end of this century and is expected to continue rising for at least the next two hundred years. It is pointed out in this comment that there has been so far no sign in any measured quantity of the positive acceleration predicted by the climate models since the 1990 and the lower bounds to sea level rises in the next few decades in every worldwide location are therefore simply the continuation of the linear trend locally measured up to present.