The copper river in the Gulf of Alaska-NASA
The world is changing before our very eyes yet most of us choose to ignore it. There has been a lot of horrible news lately regarding the rapid melting of the planets snow and ice. Irreversible melt in Antarctica, ice free arctic ocean in summer, and massive ice shelves that have held back Antarctica's glaciers for tens of thousands of years are now cracking. In Alaska, land based melting glaciers are rapidly retreating under the pressure of their own weight and the forces of gravity.
The National Snow and Ice Data Center explains how a glacier moves. "Glaciers move by internal deformation of the ice, and by sliding over the rocks and sediments at the base. Internal deformation occurs when the weight and mass of a glacier causes it to spread out due to gravity. Sliding occurs when the glacier slides on a thin layer of water at the bottom of the glacier. This water may come from glacial melting due to the pressure of the overlying ice or from water that has worked its way through cracks in the glacier. Glaciers can also readily slide on a soft sediment bed that has some water in it. This is known as basal sliding and may account for most of the movement of thin, cold glaciers on steep slopes or only 10 to 20 percent of the movement of warm, thick glaciers lying on gentle slopes.
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