Earth’s frozen places are losing ground fast. In Antarctica, melted ice spills into the ocean at rate of about 155 billion tons (140 billion metric tons) per year — an amount so confoundingly huge that it’s easier just to call it “chilling” and “unprecedented,” as a recent U.N. report did. Those numbers will only increase as humans continue polluting the air with record amounts of heat-trapping greenhouse gases.
On the frontlines of this warm-weather siege are the world’s ice shelves. Perched all around the edges of Antarctica and Greenland, ice shelves help stem the tide of melting glaciers by growing outward over the ocean like thick balconies of frost. Nearly 600,000 square miles (1.5 million square kilometers) of ice shelves surround Antarctica alone, through which 80% of the continent’s melting ice passes. However, a new study suggests, those dams of ice may have a fatal flaw in the face of Earth’s increasingly warming oceans.
In a study published yesterday (Oct. 9) in the journal Science Advances, researchers used satellite imagery to look at Antarctica’s shear margins — fragile areas near the edges of ice shelves where huge cracks tend to spread — and found a troubling pattern. Certain cracks seemed to emerge in the same spots year after year, often stretching clear across the tips of their ice shelves and carving huge chunks into the sea. These cracks were often accompanied by long, sagging troughs and large holes in the ice — suggesting that some natural force under the shelves is causing the same regions to buckle and break every year.
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