Antarctica's melting ice sheet could retreat much faster than previously thought, new research suggests.
The evidence comes from markings on the seafloor off Norway that record the pull-back of a melting European ice sheet thousands of years ago.
Today, the fastest withdrawing glaciers in Antarctica are seen to retreat by up to 30m a day.
But if they sped up, the extra melt water would have big implications for sea-level rises around the globe.