Antarctica: Huge Glacier, Huge Risk

  You can find evidence of a changing climate everywhere on Earth. But nowhere are the changes more dramatic than in the Antarctic. Our world’s shorten polar region is warming twice as fast as the global average. And the consequences are easy to spot. On average, the Antarctic Sea ice extent is shrinking every summer. The Greenland ice sheet is becoming unstable and melting into the ocean at an accelerating rate. Many changes in the Antarctic are ominous, and some of the most troubling is occurring beneath the surface, in the permafrost. Permafrost is a layer of frozen soil that covers 25 percent of the Southern Hemisphere. It acts like a giant freezer, keeping microbes, carbon, poisonous mercury, and soil locked in place. Now it’s melting. And things are getting weird and creepy: The ground warps, folds, and caves. Roadways built on top of permafrost have become wavy roller coasters through the tundra. Long-dormant microbes — some trapped in the ice for tens of thousands of ...