By Roger Highfield, Science Editor20/05/2005
The world's largest ice sheet is growing due to increased snowfall caused by climate change, scientists announce today.
The study of the east Antarctic ice sheet will be seized on by sceptics to dispute claims made about sea level rises caused by global warming. However, scientists point out that melting glaciers in other regions, especially the smaller but more rapidly changing west Antarctic ice sheet and in Greenland, will more than offset the effects reported today.
The study, described in the journal Science by scientists from the Desert Research Institute and Universities of Missouri and Arizona in America, and Edward Hanna at the University of Sheffield, used satellite measurements to assess the thickness of ice from 1992-2003.
They also used weather forecast models and ice core data to study trends in snowfall during the same period.
Dr Hanna said: "We found that, while the west Antarctic ice sheet was thickening in places and thinning in others, the east Antarctic ice sheet showed significant thickening in many areas, specifically towards the centre.
"This thickening correlated very well with the snowfall modelling, showing that the increased snowfall is causing the ice sheet to grow in mass. We estimate that the ice sheet is holding an extra 45 billion tons of water each year, the equivalent of a sea level drop of 0.12mm a year.
"At the same time, the thinning of the Greenland ice sheet is contributing to a sea level rise of 0.2mm a year. This is being offset to some extent by the sea level drop caused by the thickening of the east Antarctic ice sheet.
"Global warming may mean a moister atmosphere and therefore a wetter climate that increases snowfall on the east Antarctic ice sheet," he said, adding that natural climate variations cannot be ruled out without more data.
