The sun sets at the Davis Station, Antarctica.

Rachael Robertson

An ice shelf holding a critical glacier in Antarctica could shatter within the next five years, scientists warned on Monday during an American Geophysical Union meeting.

The Thwaites Glacier is a Florida-sized sheet that’s already responsible for about 4% of global annual sea level rise as it slowly melts into the ocean. But the glacier sits on an ice shelf vulnerable to failing due to newly detected fissures on its surface and a major fracture across the entire shelf, according to satellite images.

Hotter ocean temperatures, fueled in part by human-caused climate change, are eroding the eastern ice shelf. If the shelf breaks apart, the glacier’s contribution to sea level rise could eventually increase by as much as 25%, the scientists said.

Ice loss in Antarctica has been growing worse in recent years and research suggests that a dangerous amount of sea level will occur if global warming reaches about three degrees Celsius (5.4 degrees Fahrenheit) above preindustrial levels. The Earth has already has surpassed one degree Celsius of warming.

The cracks in the Antarctic ice shelf are similar to those in a car windshield, where a slowly growing crack reveals that the windshield is weak and a slight bump to the vehicle could prompt the windshield to immediately break apart into hundreds of pieces of glass, according to Oregon State University glaciologist Erin Pettit.

During the meeting, the scientists said they’ve targeted the weak and strong parts of the shelf and concluded that fractures will take a “zig-zag” pathway through the ice and ultimately cause the shelf to break in as little as five years.

Global sea levels will rise two to six feet by 2100 on the current trajectory, driven mainly by melting in Greenland and Antarctica, according to NASA satellite data. However, scientists have warned that projections underestimate the impact of climate change on sea level rise.

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