fig. 3.42 > If glaciers and ice shelves melt on their upper surfaces, the presence of meltwater reinforces the further loss of ice mass in three ways. A/B: The darker surfaces of lakes and streams absorb more solar energy than the brighter ice. The water warms up and promotes continued melting of ice on the glacier’s surface. The ice body thus thins from above. C/D: Meltwater that finds its way to the underside of the glacier increases the flow velocity of the ice masses. E/F: Meltwater collecting on the ice shelf deepens existing fractures and creates new ones, so that icebergs break off more often.