evidence: It doesn’t mean they’re in immediate danger of collapse. But as the Southern Hemisphere warms—and the ice sheet melts at faster rates—the risk could be rising. [...] It’s a process known as "hydrofracturing." And a new study, published yesterday in Nature, suggests that more than half of Antarctica’s ice shelves could be at risk. [...] And the combination of warming ocean waters and rising atmospheric temperatures could be a dangerous pair, he added. Antarctic ice shelves may increasingly be at risk of a double whammy: simultaneous weakening of the top and bottom.