The global sea level is higher now and is rising more rapidly than at any other time in the past 3000 years. It will continue to rise for centuries after global temperatures are stabilized, as it takes that long time for the ocean and ice sheets to adjust to a warmer climate. A significant uncertainty exists in the projections of the mean sea-level change and its regional impacts in the 21st century. Impacts and threats to many coastal cities, areas, and island states are being exacerbated by increased frequency of short-term extreme sea levels due to the superposition of tides and storm surges on rising mean sea level.
In 2009 the WCRP and IOC (Intergovernmental
Oceanographic Commission of UNESCO) established the WCRP-IOC Task Group on Sea-Level Variability and Change. The decision was made by the 30th Session of the WCRP Joint Scientific Committee (6-9 April 2009) and it was endorsed by the 25th Assembly of IOC (16-25 June 2009)
WMO/WCRP update on Sea-Level Rise (January 2010)