Scientists are learning just how fast the ice margin of Antarctica can retreat in a warming world.
They've identified features on the seafloor that indicate the ice edge was reversing at rates of up to 50m a day at the end of the last ice age.
That's roughly 10 times faster than what's observed by satellites today.
The discovery is important because it puts realistic constraints on the computer simulations that are used to project future change in the region.
"In numerical models, you play with the parameters - and they can do very strange things," said Prof Julian Dowdeswell. "But what these data are saying is that actually rates considerably higher than we get even in the satellite record on Friday were possible in the not-far-distant geological past."