Climate change keenly felt in Alaska’s national parks – ‘We used to build with a sense of permanence’
By Yereth Rosen; editing by Steve Gorman and Greg McCune
Sat Feb 12, 2011 12:43pm EST
ANCHORAGE, Alaska (Reuters) – Thawing permafrost is triggering mudslides onto a key road traveled by busloads of sightseers. Tall bushes newly sprouted on the tundra are blocking panoramic views. And glaciers are receding from convenient viewing areas, while their rapid summer melt poses new flood risks. These are just a few of the ways that a rapidly warming climate is reshaping Denali, Kenai Fjords and other national parks comprising the crown jewels of Alaska’s heritage as America’s last frontier. These and some better-known impacts — proliferation of invasive plants and fish, greater frequency and intensity of wildfires, and declines in wildlife populations that depend on sea ice and glaciers — are outlined in a recent National Park Service report. Since the mid-1970s, Alaska has warmed at three times the rate of the Lower 48 states, according to the U.S. Environmental Protection Agency. And with nearly two-thirds of U.S. national parkland located in Alaska, the issue of climate change is especially pressing there, officials say. In some far northern parks such as Gates of the Arctic, average temperatures are expected to shift in coming years from below freezing to above freezing, crossing a crucial threshold, said Bob Winfree, Alaska science adviser for the Park Service. “The effects of melting ice and thawing permafrost, I think, will be major,” Winfree said. … “Those of us that go into these places over time can definitely notice the changes,” said Jim Stratton, Alaska regional director for the National Parks and Conservation Association, an environmental organization. Some changes are obvious in Kenai Fjords National Park, a popular destination south of Anchorage known for its ice-capped peaks, tidewater glaciers and abundant marine life. The retreat of Exit Glacier, one of the park’s best-known features, has forced park managers to reroute trails through areas that were under ice just a few years ago. The glacier’s retreat also has left a sheltered pavilion that was built in the 1990s far from the spectacular views of blue ice. “We used to build these things with a sense of permanence,” said Jeff Mow, the park’s superintendent. A more ominous concern has been runoff from glacier melt. Spring and fall floods have long been common, but over the past two summers, at the peak of tourist season, the Exit Glacier entrance has been swept by big, road-closing floods, Mow said. … Another big headache is newly sprouted roadside vegetation, said Elwood Lynn, assistant superintendent at the park. “There’s a dramatic difference, if you look in old photos, in the amount of vegetation,” Lynn said. “We’ve got full-time crews cutting brush that we didn’t have in the early ’80s.” Elsewhere, accelerated erosion is taking its toll on thawed shoreline under assault from surf once held back by sea ice. At the remote Bering Land Bridge National Preserve and Cape Krusenstern National Monument in northwestern Alaska, coastal erosion poses risks to archeological resources thousands of years old and to some modern structures near the shore, according to the Park Service strategy. …
