Abstract
In classical geodesy, mean sea level has often been considered as a stable reference datum. However, research over the past decade has revealed a number of effects that complicate the classical geodetic view. One of these in particular is the discovery that global sea levels have risen in the order of 10–20 cm over the last century. It is anticipated that as global warming occurs, this rate of rise will exist. This article discusses these sea level changes, examines the possible mechanisms driving such change, and gives a scenario for the changes that might be expected to occur over the next 60 years. The scenario presented suggests that by the year 2050, global sea levels will stand 18–35 cm higher than at present.