Birth of a Berg

Our planet has warmed by 1 degree Fahrenheit since the beginning of the century, but for reasons that aren’t entirely clear, the Antarctic Peninsula--the stretch of land that reaches up toward South America--has warmed 4.5 degrees in just the past 50 years. In 1995 the warming made itself felt in a dramatic way, as this satellite image illustrates. The image shows, at the lower center, a thousand-square-mile iceberg that calved off the huge Larsen Ice Shelf sometime in January or February. At around the same time, a large chunk of the ice shelf just north of the berg disintegrated into much smaller pieces. What’s more, so did two smaller ice shelves elsewhere on the peninsula. The Antarctic gives off large icebergs maybe every three or four years, says glaciologist David Vaughan of the British Antarctic Survey. The big story for us is that three ice shelves-- which had been thought ...