In Antarctica, proof that action on climate change is more urgent than ever
The Independent (
Fears that global sea levels this century may rise faster and further than expected are supported by a study showing that 300 glaciers in
Scientists believe that the accelerated movement of glaciers in the
Instead of simply adding huge volumes of meltwater to the sea, scientists have found rising temperatures are causing glaciers as far apart as
The findings will raise concerns within the UN's Intergovernmental Panel on Climate Change (IPCC) which, earlier this year, downplayed the so-called "dynamic" nature of melting glaciers - when rising
temperatures cause them to break up quickly rather than simply melt slowly.
Using radar images taken between 1993 and 2003, scientists at the British Antarctic Survey in
The scientists believe that their findings are among the first to suggest that as glaciers being to melt they experience a physical transformation that causes an acceleration in their movement into the sea.
"We're only just now getting to grips with just how big these dynamic processes may be. There are still a lot of surprises out there," said David Vaughan, a glaciologist at the British Antarctic Survey and a
co-author of the study.
"It is yet another example of how subpolar glaciers are responding very quickly to climate change because they are close to the temperature transition from ice to water," Dr Vaughan said.
"Scientists want to know why these things are happening because that's the route to the prediction of future sea levels."
In its fourth report published in February, the IPCC said sea levels this century could rise by between 20 cms and 43cms but it accepted that this could be a serious underestimate if ice sheets and glaciers
undergo the sort of dynamic changes that existing computer models do not take fully into account.
Hamish Pritchard, a co-author of the study published in the Journal of Geophysical Research, said the findings demonstrated how melting glaciers can change in a way that speeds up their eventual
disappearance into the sea.
The study showed that rising temperatures cause glaciers to become thinner, which makes them more buoyant when resting on submerged bedrock, so allowing them to slip faster into the ocean, Dr Pritchard said.
"They are speeding up in a steady, progressive way. Warming causes widespread thinning, which causes widespread acceleration due to an increase in buoyancy. They speed up and the fronts of the glaciers break off and float away."
Chris Rapley, director of the British Antarctic Survey, said: "Without doubt we are seeing a striking global picture of ice on the retreat."