The ice shelves floating off the coast of Antarctica have been melting at a faster pace. According to a study published Thursday in the journal Science, the Antarctic ice shelves have thinned by nearly 20% in 18 years. Ice shelves are floating extensions of the permanent ice sheet. They are usually 400-500 meters thick and can be found hundreds of miles off the coast of Antarctica.

Antarctic Ice Shelf Melting Accelerates Dramatically: Study

Antarctic ice shelves melt 18%

Ice shelves act as a bulwark against the melting of Antarctic ice sheet, thus preventing the permanent collapse of glaciers in the southern continent. The study was based on satellite data provided by the European Space Agency for years between 1994 to 2012. It sheds new light on how Antarctic responds to global warming. Rapid melting of ice shelves could hasten the rise in sea levels.

Researchers said that between 1994 and 2003, the overall volume decline around Antarctica was very small. The losses in West Antarctica were almost balanced out by gains in the East Antarctica. But since 2003, gains in the east have almost disappeared, and western losses have increased dramatically. The Venable Ice Shelf in the Bellingshausen Sea and Crosson Ice Shelf in the Amundsen Sea each shrank more than 18% during the study period.

More of the land-based ice could collapse into the ocean

18% melting over a period of 18 years was a “substantial change,” said the University of California, San Diego researcher Fernando Paolo, the lead author of the study. If this rate of thinning continues, the Antarctic ice shelves will lose half of their volume in the next 200 years. If the ice shelves get too thin, more of the permanent glaciers they support would collapse into the ocean, raising the sea levels.

The melting of ice shelves doesn’t directly increase sea levels because they are already floating. But they protect the land-based ice. So, their reduction would lead to more of the land-based ice entering the ocean, which could potentially lead to an increase in sea levels.