Runaway loss of Antarctic ice may last for centuries: study

The runaway loss of ice from Antarctica as a result of global warming could last for centuries, according to a new study announced today.
By studying rocks at different elevations beside the East Antarctic Ice Sheet (EAIS), the researchers concluded that a period of rapid glacier thinning occurred in the recent geological past, and persisted for several centuries.
Satellite observations show that parts of the Antarctic ice sheet are currently thinning in response to a warming ocean.
Of particular concern is the potential for 'marine ice sheet instability', where an initial retreat of ice margins into deepening valleys could lead to continued, unstable ice loss.

The new research, led by Richard Jones, Postdoctoral Research Fellow at Victoria University of Wellington, indicates that the processes leading to instability can be initiated by just minor climate warming.
"The finding is very important for predicting Antarctica's future contribution to sea level change," said Jones.

"Particularly when considering that the EAIS contains enough vulnerable ice to raise sea level by tens of metres. It might only require a small amount of climate variation to initiate runaway ice loss, and it could continue for centuries to millennia," said Jones.
While this process has been posited for many years, the study presents the first directly recorded evidence that it has taken place in the past, providing new insight into the future behaviour of rapidly changing parts of Antarctica today.

Researchers combined numerical modelling experiments that simulate glacier retreat with geological data processed in Victoria University's cosmogenic nuclide laboratory.
The laboratory studies rare isotopes produced through the interaction of cosmic radiation with minerals on the Earth's surface, which allows for the calculation of the age of a rock surface.
"Most research has previously focused on the West Antarctic Ice Sheet, which makes these observations from East Antarctica all the more significant," said Jones.
The research was published in the journal Nature Communications.