how much could sea level rise in the 21st century
Future sea level The Intergovernmental Panel on Climate Change (2007)[1] projected sea level would reach 0.18 to 0.59 m above present by the end of the 21st century but lacked an estimate of ice flow dynamics calving.[2][3] Calving was added by Pfeffer et al. (2008)[4] indicating 0.8 to 2 m of SLR by 2100 (favouring the low end of this range). Rahmstorf (2007)[5] estimated SLR will reach 0.5 to 1.4 m by the end of the century. Pielke (2008)[6] points out that observed SLR has exceeded the best case projections thus far. These approximations and others indicate that global mean SLR may reach 1 m by the end of this century. However, sea level is highly variable and planners considering local impacts must take this variability into account.
Sea level In the UK, the Ordnance Datum (the 0 metres height on UK maps) is the mean sea level measured at Newlyn in Cornwall between 1915 and 1921. Prior to 1921, the datum was MSL at the Victoria Dock, Liverpool.