Meltwater Lakes in Antarctica Show Signs of Trouble

Antarctica is home to the largest ice mass on Earth.
Beautiful lakes have begun to appear on the top of the ice.  These lakes are called supraglacial or meltwater lakes.
Although the lakes can be beautiful, the ones scientists studied are a sign of trouble.
Scientists say Antarctica has always had supraglacial lakes appearing on the ice during the summer months. But the more lakes there are, the more unstable they make the continent’s ice shelf.Ice shelves are permanent, but floating pieces of ice that connect to the land. They form where a glacier or ice sheet reaches a coastline and into the sea. Water from the lakes can drip down through the glacier, causing the huge river of ice and snow to weaken.
lakes are partly responsible for the collapse of the Antarctica ice sheets.This is because it was covered in lakes in the years prior to collapse, and that by repeatedly filling and draining, they weaken the ice sheet, leading to its eventual disintegration.
And as temperatures rise, the team expects to see more and more lakes appearing in the continent. The scientists fear that all that meltwater could raise the world's sea levels.

Words in This Story
ice mass - n. a large piece of ice
supraglacial lake – n. any pond of liquid water on the top of a glacier
ice sheet – n. a very large and thick area of ice that covers a region
ice shelf – n. a floating sheet of ice permanently attached to a land mass
glacier – n. an large areas of ice formed from falling snow and building up over the years

The continent sits on 14 million square kilometers of rock. About 98 percent of the land surface is covered by ice.