A key Antarctic glacier just lost a huge piece of ice — the latest sign of its worrying retreat

A key Antarctic glacier just lost a huge piece of ice — the latest sign of its worrying retreat

SOURCE: The Washington Post, Yale e360 DATE: September 25, 2017 SNIP: An enormous Antarctic glacier has given up an iceberg over 100 square miles in size, the second time in two years it has lost such a large piece in a process that has scientists wondering whether its behavior is changing for the worse. The Pine Island Glacier is one of the largest in West Antarctica, a region that is currently Antarctica’s biggest ice loser. Pine Island, which loses an extraordinary 45 billion tons of ice to the ocean each year — equivalent to 1 millimeter of global sea level rise every eight years — is 25 miles wide where its floating front touches the sea, and rests on the seafloor in waters more than a half-mile deep. The single glacier alone contains 1.7 feet of potential global sea level rise and is thought to be in a process of unstable, ongoing retreat. The glacier is feared to be in a process of unstable, runaway retreat. The grounding line has been moving inland, and as it retreats, the seafloor bed dips downward, meaning that the ocean becomes even deeper and the ice becomes even thicker. Thus, further retreat should increase the rate of outward flow and lead to even more ice...
Forget That Big Iceberg–A Smaller One in the Arctic Is More Troubling

Forget That Big Iceberg–A Smaller One in the Arctic Is More Troubling

SOURCE: Scientific American DATE: July 31, 2017 SNIP: The world saw headlines about one of the largest icebergs ever calved a few weeks ago. But a smaller one on the other end of the globe might have bigger consequences. The chunk of ice, which broke free in the Arctic last week, is more worrisome to climate scientists who are watching one of Earth’s largest glaciers shed pieces in a way that stands to raise sea levels. Movement of the Petermann Glacier has sped up in recent years, dumping land-based ice into the ocean at a faster rate and drawing more ice down from the center of Greenland, said Laurence Dyke, a researcher at the Geological Survey of Denmark and Greenland. Meanwhile, the ice shelf that braces it and slows the rate of flow is disintegrating as climate change transforms the region. “You could call it the canary in the coal mine. If that big glacier there is changing quickly, and it is, it’s a worrying sign for what’s happening in the rest of Greenland,” he...