Antarctica is experiencing a sudden loss of ice mass that has many climatologists and geologists concerned over the state of the frozen continent. Since 2009, several glaciers that once held vast amounts of ice have disappeared.

The Southern Antarctic Peninsula showed little change in its quantity of ice held in an ice sheet — until six years ago, as revealed by an examination of satellite data. Suddenly, in 2009, glaciers along a strip nearly 470 miles long began to melt rapidly, shedding 14.5 trillion gallons (14.4 cubic miles) of water each year.

Over the course of the last six years, the total amount of water released from the ice sheet in this region amounts to nearly 72 cubic miles, or roughly 350,000 times the total volume of the Empire State Building. This rate of melting makes the Southern Antarctic Peninsula the second largest contributor to Antarctic sea level rise.

"The fact that so many glaciers in such a large region suddenly started to lose ice came as a surprise to us. It shows a very fast response of the ice sheet: in just a few years the dynamic regime completely shifted," said Bert Wouters from the University of Bristol.

Detection of the ice loss was witnessed by researchers examining data from the CryoSat-2 satellite, operated by the European Space Agency. From a height of roughly 450 miles above the surface of Earth, the observatory sends radar signals down to Earth, recording the amount of time the beam takes to return in order to make precise measurements of ice depth. Over five years, ice levels shrunk by an average of 13 feet per year.

The Southern Antarctic Peninsula was once thought to be one of the most stable areas of the continent.

"It appears that sometime around 2009, the ice-shelf thinning and the subsurface melting of the glaciers passed a critical threshold that triggered the sudden ice loss. However, compared to other regions in Antarctica, the Southern Peninsula is rather understudied, exactly because it did not show any changes in the past, ironically," said Wouters.

Data from the investigation revealed that the rapid changes seen on the peninsula could not be explained by temperature fluctuations in the atmosphere or variations in snowfall. Researchers believe the loss of ice sheets is driven primarily by rising temperatures in the Southern Ocean surrounding the continent.

The Gravity Recovery and Climate Experiment (GRACE) satellite was able to record small changes to the gravitational field of Earth.

Investigation of the rapid ice loss seen on the Southern Antarctic Peninsula was published in the journal Science.

Photo: Christopher Michel | Flickr

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