earth talk 5-26-05
Dear “Earth Talk”: What are the
implications for Montana’s Glacier National Park if the glaciers
there keep melting?
— Oliver Ryan, New York City
The glaciers for which Glacier National Park is named are melting away as a result of increasing global temperatures in recent decades, attributable most likely to global warming. A century ago, Grinnell Glacier, once the park’s largest, covered almost 440 acres. Today it has shrunk to just a quarter of that size. Many of the glaciers are gone altogether: According to the Sierra Club, the number of glaciers in the park has dropped from around 150 in 1850 to approximately 35 today.
Most of the glacier loss in the park has occurred since the late 1960s, when global-warming trends began to intensify. Park scientists are now worried that if nothing is done to curb global warming, by the year 2030 there may not be a single glacier left in Glacier National Park.
Glaciers form when huge ice sheets build up under snow that has slowly accumulated over time. As the snow cover mounts, the intense weight compresses the delicate snowflakes beneath the surface, gradually changing them into the ice grains that make up glaciers. During the last Ice Age, some glaciers were a mile thick, covering huge swaths of the Earth and carving out much of the topography we know today through their slow and grinding movements.
The warming of the Earth that occurred at the end of the last Ice Age — and which melted glacial ice from pole to pole — was a natural phenomenon that took place over thousands of years. Today, the carbon dioxide emissions generated over just the last half-century from industrial and automotive sources could, say scientists, lead to an equivalent amount of glacial melting within just decades, not millennia.
This process could put plants and animals, which have adapted to certain living conditions over time, in deep trouble as their habitat characteristics shift right under their feet, fins, and roots. And Glacier National Park will be no exception. For example, the lack of glaciers and snow pack there could eliminate avalanches, which perform a valuable ecosystem function by knocking down forested stands to make way for new growth in meadows. The berries that are prevalent in these meadows are a major nutrition source for the grizzly bears that call the park home. Without avalanches and the meadows they create, the park’s already stressed grizzly population could suffer a drastic decline.
Beyond such ecological implications, no one knows how a glacierless Glacier National Park might play to tourists doing their grand Western tours. If the number of visits to the park and therefore the region were to drop significantly, the local economy — now dependent on tourism revenue — could suffer debilitating losses. After all, who would visit a place called Glacier if there were no glaciers to see?
For more information: Sierra Club, www.sierraclub.org/globalwarming/articles/glacier.asp; Glacier National Park, www.nps.gov/glac/.
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