| Alaska, 1979 | |
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The glacier in this valley is in retreat, like all of those in Glacier Bay. At the mouth of the valley are two side canyons with streams instead of ice. Erosion by these streams (fluvial erosion) has swiftly cut through the basal moraine and built up an alluvial fan. Thus the characteristics of glacial and fluvial valleys are apparent in the same place.
When this region was first explored in 1794, Glacier Bay did not exist; it was a glacier, extending all the way to Cross Sound. A century later, John Muir praised the grandeur of the bay, and today it has much less ice than Muir saw.
Natural climatic changes were responsible. The modern warming of the globe is the combination of several poorly understood factors: solar cycles, oceanic circulation, human-caused changes in the atmosphere. How these affect a particular region varies from place to place, but on the whole, the world's small icefields and glaciers are shrinking. On the whole, this may be better than them all growing.
