In Montana's Glacier National Park, only 27 of the 150 mammoth ice glaciers that existed when the park was created in 1910 remain. These "jewels in the crown of the continent" took millions of years to form; they are expected to be gone in 20 years.
In Alaska, parts of the 3,000-year-old Herbert Glacier are 500 feet thick, but the glacier is melting at a rate of 200 feet per year.
Some scientists say the receding glaciers, like canaries in a coal mine, are providing an early warning system for the Earth. They say human-caused global warming is making the sea level rise and can spawn floods — called glacier outbursts — brought on by glacial melting. They say global warming is responsible for extreme weather and outbreaks of diseases throughout the world.
Bruce Molnia, a glaciologist at the United States Geological Survey, has studied Alaskan glaciers for more than 30 years. During a recent tour over the Herbert and Mendenhall glaciers in the 49th State, he said: "The whole face has collapsed in the last month... That wasn't like that when I was here in July."
Tune in to the FOX News Channel special report, "The Heat Is On: The Case of Global Warming," on Sunday, Nov. 13, at 8 p.m. and 11 p.m. EST.
Scientists say "greenhouse gases" — especially carbon dioxide and methane — emit from tailpipes and smokestacks. These gases trap heat and prevent it from escaping into space, just as glass traps heat in a greenhouse. As the gases accumulate, they say, the Earth heats up and climates change.
On a tour of Glacier National Park in Montana, USGS ecologist Dan Fagre pointed out evidence of glacial deterioration.
Contrasting present conditions with a photo from 1938 in which a man is standing on a 60-foot-high slab of ice, Fagre said: "There's no ice here at this time; it's all just liquid water."
"When we see a place like this changing," he said, "we can attribute it to climate change and to the human influence on the planet."
Harvard's Paul Epstein, a physician and an expert on emerging diseases, blames global warming for recent droughts in Spain and Portugal, as well as heavy rains in other parts of Europe, and says the climate change is linked to outbreaks of malaria and cholera in Asia and Africa and an increase in asthma cases in the United States.
"We now have 25 million people with asthma; 9 million of them are children," Epstein said.
Some scientists also say this year's record number of Atlantic hurricanes is due to global warming.
"By warming the surface of the ocean, greenhouse gases are providing the feedstock for more and more intense hurricanes," said Michael Oppenheimer, who reviews the latest scientific reports for a U.N.-sponsored intergovernmental panel on climate change.
Some advocates say industry is largely responsible for global warming, and that large corporations should be held to their promises.
Said Dan Becker, director of the global warming program at the Sierra Club: "When a company comes along [and] says we're trying to solve the global warming problem, that makes you think they are a green company, [that] they are trying to help. We are trying to prevent the green-washing of America by corporate polluters who are claiming to solve the problem but actually making it worse."
Becker points to General Electric as a company that he said claims to be environmentally concerned but fails to honor promises with actions.
"GE is a giant company... [But] their PCBs that they've dumped into the Hudson River — for decades — have poisoned that river."
In August, GE's CEO Jeff Immelt acknowledged in a Forbes Magazine article that the company's expensive TV and print campaign, "Ecomagination," was little more than a sales pitch.
"It's primarily that," Immelt said. "In essence, it's a way to sell more products and services."
General Electric declined to speak to FOX News for this report.
Another company that has been on the Sierra Club's list of polluters is Ford. But Becker sees some progress from the automaker.
"For years we criticized Ford Motor Co. for making gas-guzzlers," he said. "So when they finally began to make hybrid vehicles, we felt it was important that we recognize that progress."
But the technology does not come cheap. Consumers can expect to pay thousands more for hybrid engines and while they are popular, with impressive fuel economy, they're only considered an interim fix to the fossil fuel problem.
The cost of stemming global warming is steep. The Kyoto Protocol, which required the United States to cut greenhouse gas emissions by 7 percent and other industrial nations to cut emissions by 5 percent by 2012, was pushed as a solution.
But the Bush administration opted out of Kyoto because the cost to companies and American taxpayers was considered too high.
Bush defended that decision in July, saying Kyoto was not broad enough because "many developing nations weren't included."
The United States likely will negotiate an agreement that operates with different emissions limits in future international summits.
Eyes on the Future
About an hour north of Portland, Maine, at Camp Chewonki in Wiscasset, campers learn about global warming and alternative energy sources. They use some unorthodox technologies to produce about 10 percent of their electricity.
They collect the sun's rays with rooftop solar panels. And they've learned that something as disposable as cooking oil can be recycled for other purposes.
"After you make French fries, you can take the oil out of the fryolators ... and we use it in vehicles here at Chewonki," program coordinator Peter Arnold said.
"We have a huge number of forests," he added. "We have lots of rivers. We need to care for that. ... And if [the] environment is degrading because of the way we're doing our fuel business, we need to change that."