"What surprised us was how quickly it happened. It's pretty alarming. Even 10 years ago, scientists assumed that when global warming changes occur that it would happen gradually, so that perhaps we expected these ice shelves just to melt away quite slowly. But the big surpirse is that, for one, they are going, but, secondly, that when they do go, they just go suddenly. It's all at once, in the span of an hour."