Imagine the Grand Canyon – so achingly vast and vacant – filled to the rim with the daily din of machinery, like the background hum a big city.
Envision no more glaciers at Montana’s Glacier National Park, where since 1979 the average temperature has nudged two degrees higher.
Following a pair of recent studies that exposed man-made and climate-caused deterioration at those two iconic American attractions, environmentalists are raising new concerns about the future health of all 58 U.S. national parks in a time marked by barren budgets, rising energy cravings and warming skies.
At Saguaro National Park in Arizona, the very species that gave the refuge its name – the tree-sized, saguaro cactus – is imperiled by an invasive, fire-prone, African weed first introduced to U.S. soil 80 years ago as livestock forage. On private land outside Utah’s Bryce Canyon National Park, a coal company has been cleared to launch a 440-acre strip mine that, ecologists say, could pollute waterways and send dust clouds over the park. At Great Smoky Mountains National Park in Tennessee and North Carolina, a centuries-old canopy of hemlock trees is being eaten away by the woolly adelgid, an Asian insect first spotted in the park in 2002 – probably carried in unknowingly by a tourist, according to one park expert.
Don't miss these Travel stories
Lords of the gourd compete for Punkin Chunkin honors
With teams using more than 100 unique apparatuses to launch globular projectiles a half-mile or more, the 27th annual World Championship Punkin Chunkin event is our pick as November’s Weird Festival of the Month.
- Airports, airlines work hard to return your lost items
- Expert: Tourist hordes threaten Sistine Chapel's art
- MGM Grand wants Las Vegas guests to Stay Well
- Report: Airlines collecting $36.1B in fees this year
- Lords of the gourd compete for Punkin Chunkin honors
“So we have these threats,” said David Nimkin, southwest regional director of the National Parks Conservation Association, the agency that last week released a status report on the Grand Canyon. “I think sometimes there is a level of complacency where we tend to think of our national parks as already being protected.”Video: Park rangers to tourists: Put gadgets away (on this page)
But beyond climate change, and beyond mining and drilling projects on the fringes of other national parks, one of the most pressing dangers to these precious places is the people who most adore them.
The unnatural footprint left by hundreds of millions of park visitors is growing, environmentalists say. Hikers wander off marked trails, trampling vegetation. Vehicles clog park roads and sully the air with tailpipe emissions. Tourists leave behind water bottles and other scraps of litter. Above many national parks, sightseeing planes and helicopters buzz.
“We really count on the visitor having a sense of ownership of national parks,” said Jeffrey G. Olson, a public affairs officer with the National Park Service. “We remind them [the] parks are here for them to enjoy and ask they help make sure they are here for future generations, too.”
But the conga lines of tourists and cars are getting longer. As the U.S. economy turned sour, park visits rose. In 2009, 285 million people spent a collective 1.25 billion hours inside the national parks, the highest numbers since 2000, according to NPS figures.
“Traffic hassles in a national park, you ask?” Olson said. “Here’s one: finding a parking spot at the Logan Pass Visitors Center in Glacier National Park.”
“I don’t want to say the future is bleak” for the parks, given the man-made degradation, said Nimkin. “I mean, we can do something about it.” One change he hopes to see is a federally-mandated cap on the number of air tours over the Grand Canyon, no-flight “respite” periods during certain months, and a relocation of flight routes away from some rim edges and other popular hiking and backpacking spots. An increase in sightseeing flights could eventually fill the canyon with the “background drone we have in our cities,” Nimkin said.Slideshow: America's national parks (on this page)
“Think about your time in a special place: it’s the sound of the loon on the lake; it’s the sound of the wind in the trees,” he said. “The full richness of the experience is so profoundly enhanced by that sense.”
When the NPS was created in 1916 to oversee the parks, the understanding was the federal agency would maintain and protect those sanctuaries, Nimkin added. “They would be places that our children and grandchildren would enjoy, and I think we need to uphold that bargain.”
At NPS, Olson said rangers (and signs) have long urged visitors to stay on the marked trails and to park in designated areas and ride shuttles through the parks. At Glacier, Grand Canyon and Zion national parks, bus systems now “help ease traffic congestion, reduce greenhouse gas emissions and make a park visit more fun and relaxing.
But several frequent park users said environmental groups must remember that the national parks are meant to be hiked, driven and rafted or absorbed from above, that they were specially designated as places to be seen, felt and touched by people. And some – or perhaps much – of the deterioration of the park landscapes is simply due to our planet’s normal aging, some of those users maintain.
“I do believe that part of this is ... just natural decay. The earth does break down after a while,” said Ken Donaldson, a life coach and mental health counselor in Tampa, Fla., who spent much of his childhood – and now his adulthood – walking through more than 20 national parks. “What do we do, stop people from coming?” He suggests that “perhaps a scheduling system might create better management” of the parks, and he advocates a cap on the number of daily visitors.Slideshow: America’s lesser-known national parks (on this page)
There’s no question that “much of the pressure felt by our national parks originates from beyond park borders,” said Steven Silberberg, a Hull, Mass.-based backpacker who has visited at least six national parks, including Yosemite. “For example, ranchers kill bison all the time just outside the borders of Yellowstone National park for fear that their cattle will contact brucellosis. They also kill wolves and bears because they fear losing cattle ...
“Ultimately, I think one problem is that we expect the national parks to be static museum exhibits, when they are ever-changing dynamic landscapes subject to the same forces that the rest of the world experiences, from erosion to global warming to tectonic activity,” added Silberberg, owner and operator of Fitpacking, a company that guides people on backpacking adventure vacations to help them get in shape.
America’s day starts at Acadia
This national jewel is home to our nation’s first sunrise.
- America’s day starts at Acadia
Lesser-known national parks
Unique landscape, history and culture.
- Lesser-known national parks
Texas rancher and artist Pablo Solomon – a self-described environmentalist since the first Earth Day in 1970 – suggests the parks adopt “defined use areas” for various crowds. “Some for tourists, some for serious hikers, some to just drive or ride the tram through,” he said. “The most popular and accessible parks are over run. [But] there are solutions.”
Above Great Smoky Mountains National Park, Dan Haynes believes he’s at the forefront of one of those solutions: he owns and operates Scenic Helicopter Tours, which is based in Sevierville, Tenn. The Air Tour Management Act of 2000, he said, already limits him to 1,800 sightseeing flights annually.
“As for the impact of air tours over the parks, I believe [they have] the least negative impact [on] the environment – but the worst perceived impact by those enjoying the parks from the ground,” Haynes said “Helicopters are generally 1,000 feet or higher above the ground and fly at speeds above 100 miles per hour. They leave no footprints, no trash and offer many people a fantastic view ... In short, we are not around long and we leave no trace.
“I’ve never been to the Grand Canyon,” Haynes added. “But wasn’t it created by erosion? Sorry, I just had to mention that.”
© 2013 msnbc.com. Reprints