Understanding sea-level rise and its implications for the future
By Abdul Ghani Nasir
BANGI, Jun 25 – Sea-level will continue to rise this century and beyond causing changes which will be felt through extreme climatic events and in particular causing coastal floodings and erosion. 
Dr John Church, from the Centre for Australian Weather and Climate Research said increases in the frequency and intensity of coastal floodings that have already been observed on the Australian east and west coasts will continue into the 21st century.
“Sea levels will continue to rise well beyond 2100, with the possibility of greenhouse gas concentrations crossing critical thresholds leading to sea-level rise of metres in coming centuries,” he said at an IKLIM public lecture at the Senate Room, Chancellory, UKM today.
An important but still uncertain component in the weather changes is the contribution of the Greenland and Antarctic Ice Sheets.
Dr Church said that there has been significant progress in understanding sea-level rise over the last two decades as a result of new satellite and in situ observation systems, the exploitation of historical data including paleo sea-level data and improved models of the climate system.
“The rate of sea level has increased from the 19th to the 20th century and since 1993 has been rising at over 3 mm per year. The main contributions are ocean thermal expansion, the melting of glaciers, with smaller contributions from the ice sheets of Greenland and Antarctica and changes in terrestrial storage. It now appears that the ice sheets are making an increasingly important contribution.
“Perhaps surprisingly, volcanic eruptions have a link to the rate of sea-level rise, particularly though changes in ocean heat content,” he said.
Since the early 1990s, sea level has been rising at close to the upper end of the Intergovermental Panel on Climate Change (IPCC) Third and Fourth Assessment Report projections.
Despite the importance of sea-level rise, the last two IPCC reports have not been able to satisfactorily close the sea-level budget. Updated estimates of the observed rate of rise from both satellite altimeter and in situ observations together with estimates from all of the major contributors to sea-level change has now satisfactorily explained the observed rise over the last half century.
Another speaker, Prof. Dr Thomas Stocker, from the University of Bern, Switzerland replying to a question called on countries most likely to be affected by the phenomenon to take appropriate measures from now and not wait until its too late.
DR Stocker, who is also the Co-Chair of the IPCC Working Group I, said small island states must legislate actions to avoid being engulfed by the effects of rise in sea-levels.
The two climatic experts are here with about 100 leading world experts on weather changes to discuss issues related to sea level rise, including ice sheet dynamics and ice sheet instabilities. They were in Kuala Lumpur to attend the IPCC Workshop on Sea Level Rise and Ice Sheet Instabilities from June 21-24.
Chairman of the Local Organising Committee, Prof Fredolin Tangang, Head of the Research Centre for Tropical Climate Change System (IKLIM) of the Faculty of Science and Technology, Universiti Kebangsaan Malaysia, is also the Vice-Chair of Working Group I of the IPCC.