(CNN) -- As recently as 100 years ago, Montana's Glacier National Park had more than 150 glaciers throughout its more than one million acres.

In 2005 only 27 remained. Today the total is down to a just 25 and those that are left are mere remnants of their former frozen selves.

With warmer temperatures and changes to the water cycle, scientists predict Glacier National Park will be glacier-free by 2030.

Daniel Fagre, a U.S. Geological Survey (USGS) ecologist who works at the national park believes that even those estimates are too conservative and says the park's namesakes will be gone about ten years ahead of their predicted demise.

"The glaciers have been around for the last seven thousand years," he told CNN, "and if we are going to lose them in the next 10 or 20 years that is a pretty radical shift."

The rapid melting of glaciers has led scientists to believe that mountains are more susceptible to global warming than the lowlands beneath them.

"Mountain ecosystems have been changing about twice as fast as the rest of the globe. We have had temperature increases that are two times greater than the average," said Fagre.

Many scientists are now concerned about the cascading effects on the landscape and the consequences for all species -- including humans.

"Many people are directly dependent on the water coming out of mountains and in the arid western United States that figure is much larger, it is about 85 percent," said Fagre.

"So even if you live a long ways a way you are tied to the water in mountains and so we have a lot of concerns of future climate change scenarios."

Fagre says mountains are the "water towers of the world" with 70 percent of the world's fresh water frozen in glaciers.

CNN traveled to the edge of Grinnell glacier that is at an altitude averaging 7,000 feet (2,100 meters) and was named after George Bird Grinnell, an early American conservationist and explorer.

"When George Grinnell came here in 1887 he described this place as being a thousand foot high in ice and this entire basin was filled to the mountaintop," said Fagre. "Now I stand beside a lake that is 65 meters or 187 feet deep."

We could see chunks of ice falling off, and others just dripping away. Fagre bent down to show us what's underneath the thin edge of the glacier.

"Look under here and you can see there is a lot of mucky sauce stuff and this is a lot of the rock flour ground by the glacier because it has been dragging rocks across the underlying rock layer and rubbing those two together creating this very fine material," he said.

"Many people would not be impressed by this little dirty glacier that seems to be obviously falling apart, that has become very tiny and decrepit -- and people often think about glaciers as these beautiful white expansive, blue colors - but those are healthy glaciers and this one is not. This one is on its last legs."

In 1997, USGS Physical Scientist Lisa McKeon and Fagre started the Repeat Photography Project at Glacier National Park tracking down old photographs of the park's glaciers taken by first explorers in the 1900s and comparing them with their own images. View the historical images here

McKeon and other USGS scientists try to re-photograph the exact spot where the historic photograph was taken, though it's not always possible when the original photographer was standing on ice that is now long gone.

"If you look at these pictures, you cannot say they haven't changed over time. It's very obvious," says McKeon.

Glacier National Park is celebrating its 100th anniversary this year but soon the glaciers that gave the park its name will be gone.

"Glacier National Park has been the poster child park for climate change for a lot of people in the country and I think that there has been pretty sensational news about the glaciers disappearing in fairly short order," says Chas Cartwright, Glacier National Park Superintendent.

"There is a lot less water coming off the mountain. There are dramatic changes in vegetation. It begs the question: how is that going to impact wildlife in this park?"

Many of the plant and animal species that call the park home require cold water, meaning the ecosystem of the park may change dramatically when the glaciers are gone.

There is a general consensus that man is contributing to the planet's changing climate. Some skeptics remain, but Dan Fagre isn't one of them.

"I think on a global scale when you look at all the ice disappearing all around the world, there is no other explanation for that then climate change that is driven by people," he said.

What is beyond doubt is that whatever the causes magnificent and environmentally crucial glaciers around the world are retreating: a loss to nature and to the human species.