Sub-glacier terrain affects sea levels

Fresh research into glaciers could help scientists better predict the impact of changing climates on global sea levels.

Scientists have shown for the first time that the terrain beneath glaciers influences how much glacier melt contributes to fluctuations in sea levels.

Researchers say the study will improve their understanding of how ice sheet movements have affected sea levels in the past.

New research will also enable more accurate projections of future change.

Ice age evidence

Scientists from the University studied the Slessor glacier in the Weddell Sea bay in Antarctica.

They found surprising evidence that ice thickness in the region has not changed markedly since the last ice age.

Impact on thickness

Researchers say that during the last ice age, sea levels were lower.

This would be expected to increase the distance over which the ice travelled on land, thickening as it moved slowly towards the sea.

However, a large trough in the land caused the glacier to float instead.

Floating ice moves more quickly and is prevented from thickening.

This means the ice thickness has not varied markedly with climate or sea level changes and has had little impact on sea levels or the volume of ice in Antarctica.

Sea level changes

Being able to anticipate the dynamics of the ice sheet in response to changing climates helps scientists predict shifts in global sea levels.

The study was funded by the Natural Environment Research Council and Scottish Alliance for Geoscience, Environment and Society.

Findings were published in Earth and Planetary Science Letters and unveiled at the International Symposium of Antarctic Earth Science in Edinburgh.

This finding is remarkable. We expected to show that the Slessor glacier had thinned significantly since the last ice age, in common with other glaciers in Antarctica. But it is possible to step off the glacier and on to rocks that have been untouched by ice for more than 100,000 years. To understand the behaviour of big glaciers, it is important to understand their landscapes.

Dr Andrew HeinSchool of GeoSciences
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