New projections show 'how ice loss will add to 'uneven' rising sea levels globally'



New projections show `how ice loss will add to `uneven` rising sea levels globally` London: Sophisticated computer modelling has shown how sea-level will rise over the coming century could affect some regions far more than others.

The model shows that parts of the Pacific will see the highest rates of rise while some polar regions will actually experience falls in relative sea levels due to the ways sea, land and ice interact globally.

Reporting in the journal Geophysical Research Letters researchers have looked ahead to the year 2100 to show how ice loss will continue to add to rising sea levels.

Scientists have known for some time that sea level rise around the globe will not be uniform, but in this study the team of ice2sea researchers show in great detail the global pattern of sea-level rise that would result from two scenarios of ice-loss from glaciers and ice sheets.

The team, from Italy's University of Urbino and the UK's University of Bristol, found that ice melt from glaciers, and the Greenland and Antarctic ice sheets, is likely to be of critical importance to regional sea-level change in the Equatorial Pacific Ocean where the sea level rise would be greater than the average increase across the globe.

This will affect in particular, Western Australia, Oceania and the small atolls and islands in this region, including Hawaii.

The study focused on three effects that lead to global mean sea-level rise being unequally distributed around the world.

Firstly, land is subsiding and emerging due to a massive loss of ice at the end of the last ice age 10,000 years ago when billions of tons of ice covering parts of North America and Europe melted. This caused a major redistribution of mass on the Earth, but the crust responds to such changes so slowly that it is still deforming.

Secondly, the warming of the oceans leads to a change in the distribution of water across the globe.

Thirdly the sheer mass of water held in ice at the frozen continents like Antarctica and Greenland exerts a gravitational pull on the surrounding liquid water, pulling in enormous amounts of water and raising the sea-level close to those continents.

As the ice melts its pull decreases and the water previously attracted rushes away to be redistributed around the globe.

The team considered two scenarios in its modelling. One was the "most likely" or "mid-range" and the other closer to the upper limit of what could happen.

"The total rise in some areas of the equatorial oceans worst affected by the terrestrial ice melting could be 60cm if a mid-range sea-level rise is projected, and the warming of the oceans is also taken into account," Professor Spada said.

"In the last couple of years programmes like ice2sea have made great strides in predicting global average sea-level rise. The urgent job now is to understand how global the sea-level rise will be shared out around the world's coastlines. Only by doing this can we really help people understand the risks and prepare for the future," David Vaughan, ice2sea programme coordinator, said.

"This is the first study to examine the regional pattern of sea level changes using sophisticated model predictions of the wastage of glaciers and ice sheets over the next century," Co-author Jonathan Bamber, of Bristol University, said.

ANI