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US Glaciers Vanishing Faster Than Feared
13 Oct
Summary
- US glaciers have shrunk by 35% since the mid-20th century.
- Over 300 glaciers have disappeared, more than anticipated.
- Fastest melting glaciers lose half a meter of ice thickness annually.
Glaciers in the contiguous United States, once covering 562 sq km across six western states in the mid-20th century, have experienced a dramatic 35% reduction in area. Researchers discovered that over 300 glaciers have vanished, a number exceeding their initial projections. These shrinking ice bodies underscore the extreme vulnerability of mountain glaciers to escalating global temperatures.
While large glaciers exist in Alaska and Greenland, those in the contiguous US are considerably smaller, averaging about a quarter of a square kilometer. Glaciers in the Rocky Mountains and Sierra Nevada owe their survival to unique topographic positions that offer protection from direct sun and increased snow accumulation from avalanches.
The Beartooth-Absaroka Mountains in Montana are experiencing the most rapid ice loss, with glaciers thinning by about half a meter annually. In contrast, Washington's glaciers on Mount Rainier and Mount Baker are shrinking at a slower rate, approximately half a foot per year, due to cooler summers and heavier snowfall.
Projections suggest that many glaciers, like those on Washington's Olympic Peninsula, could disappear by 2070. The receding ice poses significant risks, including the disruption of water supply to alpine ecosystems, especially during dry late summers. Furthermore, melting glaciers can destabilize moraines, increasing the likelihood of landslides and debris flows on steep volcanic slopes, a hazard observed previously on Mount Hood and Mount Rainier.
