Climate change: Study underpins key idea in Antarctic ice loss

It's long been suspected but scientists can now show conclusively that thinning in the ring of floating ice around Antarctica is driving mass loss from the interior of the continent.

A new study finds the diminishing thickness of ice shelves is matched almost exactly by an acceleration in the glaciers feeding in behind them.

What's more, the linkage is immediate, BBC News reports, citing the new finding.

It means we can't rely on a lag in the system to delay the rise in sea-levels as shelves melt in a warmer world.

The glaciers will speed up in tandem, dumping their mass in the ocean.

"The response is essentially instantaneous," said Prof Hilmar Gudmundsson from Northumbria University, UK.

"If you thin the ice shelves today, the increase in flow of the ice upstream will increase today - not tomorrow, not in 10 or 100 years from now; it will happen immediately," he told BBC News.

The edge of Antarctica is bounded by thick platforms of floating ice. These "shelves" have formed as the continent's many glaciers have drained off the land into the sea.

On entering the water, their buoyant ice fronts have lifted and joined together to form a single protrusion.

But these shelves are being besieged by the invasion of warm ocean water that's now eating their undersides. And satellite data over the past 25 years has shown many to be thinning as a consequence.

"That's a problem because the ice shelves act as a kind of architectural buttress, slowing the movement of the ice sheet behind them," explained Prof Helen Fricker, a satellite expert from the Scripps Institution of Oceanography, US. "So, if you thin an ice shelf, the grounded ice behind can speed up, but what we didn't know was by how much - and that's where our work with Hilmar and his modelling comes in."