填空题 The Larsen B ice shelf covered more than 3,000 square kilometers and was {{U}} {{U}} 1 {{/U}} {{/U}}meters thick until its northern part {{U}} {{U}} 2 {{/U}} {{/U}}in the 1990s. Three years ago, the central part also broke up.
An international team of researchers used data collected from six {{U}} {{U}} 3 {{/U}} {{/U}}near the former ice shelf to show the shelf had been {{U}} {{U}} 4 {{/U}} {{/U}}for at least {{U}} {{U}} 5 {{/U}} {{/U}}years or since the last ice age.
The {{U}} {{U}} 6 {{/U}} {{/U}}therefore goes beyond what would be expected naturally at the time. Rather, the {{U}} {{U}} 7 {{/U}} {{/U}}is likely the result of {{U}} {{U}} 8 {{/U}} {{/U}}due to melting from underneath, as well as short-term {{U}} {{U}} 9 {{/U}} {{/U}}from global climate change, the researchers suggest.
Then in five years, the shelf shrunk by {{U}} {{U}} 10 {{/U}} {{/U}}square kilometers, say scientists who found the break up caused changes in {{U}} {{U}} 11 {{/U}} {{/U}}in the area.
"As the ice shelves are disintegrating, the {{U}} {{U}} 12 {{/U}} {{/U}}that are feeding them from the land are {{U}} {{U}} 13 {{/U}} {{/U}}," said Robert Gilbert, a {{U}} {{U}} 14 {{/U}} {{/U}}at Queen's University in Kingston, Ont.
Glaciers are no longer being held back from the ice shelf, and are pushing {{U}} {{U}} 15 {{/U}} {{/U}}into the sea, said Gilbert, one of the co-authors of the study in {{U}} {{U}} 16 {{/U}} {{/U}}of the Journal Nature.
As the glaciers melt, global sea levels could change more than {{U}} {{U}} 17 {{/U}} {{/U}}, he said. Flooding could result in {{U}} {{U}} 18 {{/U}} {{/U}}.
Scientists are now watching to see if the {{U}} {{U}} 19 {{/U}} {{/U}}of the Larsen ice shelf, the coldest part of {{U}} {{U}} 20 {{/U}} {{/U}}, is going to break up.