The collapse of Antarctica's giant Larsen B Ice Shelf in 2002 was probably caused by warming at the surface rather than by instability at the bottom of the ice sheet.

Eugene Domack at the University of South Florida in St Petersburg and his colleagues mapped the sea floor below where the shelf used to be. They also analysed marine sediment cores to reconstruct characteristics of the ice shelf's grounding zone — where the floating ice shelf meets underlying bedrock — before the ice collapsed.

They found that this zone had remained stationary for some 12,000 years, challenging the idea that structural changes at the bottom of the ice shelf might have caused Larsen B's disintegration.

The findings could inform estimates of how much Antarctic melting will contribute to future sea level rise, the authors say.

Science 345, 1354–1358 (2014)