The weak underbelly of a giant Antarctic ice sheet just lost a berg more than four times the size of Manhattan

The Sentinel-1 satellite captured this image of a 100-square-mile chunk of ice calving from West Antarctica's Pine Island Glacier on September 23, 2017. (Source: Stef Lhermitte) We've now got yet another worrying sign that human-caused warming is causing the behemoth West Antarctic Ice Sheet to come unglued, threatening to raise sea level by 10 feet over time. You can see that sign in the image above from the Sentinel-1 satellite. The image shows a 103-square-mile tabular iceberg — equal in size to four and a half Manhattan islands — breaking off from the floating edge of the Pine Island Glacier in West Antarctica on September 23rd. It was posted to Twitter by Stef Lhermitte, a remote sensing expert at Delft University of Technology in the Netherlands. The glacier is like a cork in a bottle, helping to restrain nearly 10 percent of the West Antarctic Ice Sheet from pouring out ...