By Nick Bascom
When the last ice age was coming to a close about 19,000 years ago, the ice sheets that cover Antarctica began to shrink to their current sizes at about the same time as those in the Arctic, a new study finds.
That implies that the East Antarctic Ice Sheet, long thought to be relatively stable compared with the western side of the ice-clad continent, “is in fact, not so stable,” says geologist Michael Weber of the University of Cologne, Germany. And if the much larger East Antarctic Ice Sheet were to break off into the Weddell Sea, the resulting sea level rise would be tremendous, says Weber, who, with his colleagues, reports the findings in the Dec. 2 Science.
“Before our study, people thought Antarctic ice sheets began their retreat around 14,000 years ago,” says Weber. After gathering data from samples of deep-sea sediment plumbed from the Weddell Sea off East Antarctica, the researchers now suggest that Antarctic glaciers started to shrink 5,000 years earlier, around the same time as their counterparts in the Northern Hemisphere.