'An underwater ridge could explain why a major glacier in the Antarctic is melting more quickly than ever before, according to a new study. Scientists used a robot submarine to make a 3D map of the ocean under the ice shelf at the end of the Pine Island Glacier in western Antarctica/They found that the ice was no longer resting on a subsea ridge that had slowed the glacier's slide until the early 1970s. The discovery means that the glacier's more rapid melting in recent years could be due to the flow of warmer sea water beneath it rather than climate change, as had previously been believed...Read more: