The unprecedented collapse of an ice-shelf in Antarctica could indirectly lead to a significant 51 in global sea levels, researchers say.
The Larsen B ice shelf covered more than 3 000 square kilometers and was 200 meters thick until its northern part disintegrated in the 1990s. Three years ago, the central part also 52 .
An international team of researchers used data collected from six sediment cores near the former ice shelf to show the shelf had been relatively 53 for at least 10 000 years or since the last ice age. The collapse therefore goes beyond what 54 naturally at the time. Rather, the demise is likely the result of long-term thinning due to melting from underneath, as 55 short-term surface melting from global climate change, the researchers suggest.
Then in five years, the shelf shrunk by 5 700 square kilometers, say scientists who found the break up caused changes in currents and species in the area.
"As the ice shelves are 56 the glaciers that are feeding them from the land are surging forward," said Robert Gilbert, a geography professor at Queen's University in Kingston, Ont.
Glaciers are no longer being held 57 the ice shelf, and are pushing icebergs into the sea, said Gilbert, one of the co-authors of the study in Thursday's issue of the journal Nature.
As the glaciers melt, global sea levels could change 58 predicted, he said. Flooding 59 result in low-lying areas.
Scientists are now watching to see 60 the most southern part of the Larsen ice shelf, the coldest part of Antarctica, is going to break up.