How Climate Change is Transforming Our Nation's Treasured Parks

Our skiff slips quietly past an indifferent crocodile and powers across a shallow bay. We're headed to Cape Sable at the southern tip of Florida, in Everglades National Park. The breeze is warm and moist; the sky soft with cottony clouds. Mangroves along the water's edge brace themselves -- and the coast -- by growing stilts. A trio of pelicans cruises above us, and the silver flash of a tarpon cuts the water's surface. "Eighty pounds," shouts the fisherman among us. And that's just a little one.

Our skipper, a weathered, gray-haired wildlife biologist named Oron "Sonny" Bass, spends as much time as he can out here amid the teeming life of Florida Bay. Has he ever been stranded? He laughs. Lots of times. He's learned to bring a mosquito suit, a gas stove, some coffee, and a 20-foot pole. That way, if his engine dies and he has to spend the night, he won't get eaten alive, he can have coffee in the morning, and he can use the pole to push toward home.

The first national parks were established for their scenery or their history, but in 1947 Congress placed Everglades National Park in the system for its biological bounty. Its 1.5 million acres sustain a rare combination of temperate and subtropical species -- orchids and oaks, flamingos and flickers, crocodiles and alligators.

Now, as warming air and oceans melt ice at the poles, a slow-moving tsunami of saltwater is headed toward the Everglades. A sea-level rise of three feet by 2100 (the high end of the range projected by the National Research Council) would inundate 60 percent of the park's lands. "We're incredibly vulnerable," says Everglades superintendent Dan Kimball.

Global warming has already had an impact on other natural treasures. Glacier National Park had 150 gla-ciers when it was founded in 1910. Now it has only 25, and they'll all be gone, or nearly so, by 2030; staffers joke about renaming it "Puddles National Park." The famed ice caves at Mt. Rainier have disappeared. Half the reef-building corals in Virgin Islands National Park have succumbed to bleaching and disease. Habitat is shrinking for high-elevation species such as pikas and alpine chipmunks in Yosemite and Great Basin. Heat and drought are helping bark and pine beetles kill broad swaths of forest in Bandelier and Rocky Mountain and fueling wildfires throughout the West.

Some 275 million people visited America's national parks in 2007. And part of what they came for -- the grand vistas, for instance -- will still be around for our children's grandchildren. But many plants and animals that inhabit the parks won't last that long. United Nations scientists say that 20 to 30 percent of Earth's species will be at risk of extinction by 2100 -- even if we reduce our greenhouse-gas emissions 80 percent by the middle of this century. Which species survive will depend in part on what actions humans take in the next few years.

I recently visited two of the most vulnerable national parks, Everglades and Glacier, to see what climate change has done so far and to ask what park managers and scientists intend to do about it. If the National Park Service is America's Noah, I wanted to see how the ark was coming along.

To get a good look at what climate change has wrought, there's no better vantage point than Glacier. Tucked away along Montana's Ca-nadian border, it's a heartthrob of a park, with dizzying snowcapped spires and glistening waterfalls. Its waters flow all the way to the Pacific, Hudson Bay, and the Gulf of Mexico, making it the "crown of the continent." A short stroll off Going-to-the-Sun Road can bring a visitor face-to-face with a mountain goat or a bighorn sheep. All of the West's big native carnivores are still here -- black bears, grizzlies, wolves, wolverines, cougars. But melting ice is the latest tourist attraction. The number of visitors rose by 20 percent between 2000 and 2007, in part because people want to behold the glaciers before they disappear.