Editors' pick: Originally published June 8.
Those who have visited glaciers say the first view is a moment so stunning your breath gets caught in your throat.
The size is staggering. The colors are otherworldly. And the landscape is unlike anything else on earth.
"What you see is a landscape that is totally different then anything you've ever witnessed," says Bryan Mark, a scientist at the Byrd Polar and Climate Research Center at Ohio State University. "It's not devoid of life - there's fascinating interfaces with plants and biology. And you get this sense that you are closer to the sky. There's cloud formations you've never seen before."
The chance to witness such beauty and magnificence is just part of the reason why travelers make pilgrimages to the world's glaciers.
In some countries, such as Peru, glaciers have religious or spiritual significance and are the focus of fascinating annual cultural festivals involving tens of thousands of people worshiping Father Earth.
And many other visitors are likely inspired by the notion that it's now or never. And therein lies the controversy.
A recent Smithsonian article urged those interested in glacier viewing to hurry up and visit them before they're gone, eliminated by global warming.
It's the type of commentary that inspires complete frustration among those who believe that encouraging increased travel to glaciers will speed up their demise (due to the associated carbon emissions tied to the act of travel, among other things).
On the other end of the spectrum are those who say there is no better way to help people understand the effects of global warming, then to show them firsthand.
"In a way, it's a cop out when people say things like, 'If someone didn't go see a glacier, they would just stay home,'" says celebrated glaciochemist Sarah Aciego, who founded Big Chill Adventures. "People have a choice of where they're going to go...It's really important for people to see this themselves. The people who go, have a better understanding. Then they start asking questions and it's easier to have an intelligent scientific discussion when someone is standing right there and can see exactly what I'm talking about."
Wherever you happen to stand on this debate, the fact is that glaciers are retreating at a stunning pace. And seeing one in person is an experience unlike any other.
Here's a snapshot of what a handful of professionals and locals have to say about traveling to some of the world's most iconic remaining glaciers.
Peru is home to the largest mass of tropical glaciers in the world, and most are in the Cordillera Blanca, or White Mountains.
Glaciers in the Cordillera Blanca have decreased by 25% since 1987, according to a study published by Elsevier, which noted that overall, glacier change in the area is accelerating.
Researchers at the French Research Institute for Development (IRD) in Marseilles, meanwhile, have found that the glaciated area in the tropical Andes is now decreasing by 3% a year.
None of which is news to Rick Vecchio, a former AP reporter who covered Peru for years and who now lives in the country, working as director of development and marketing for the travel company Fertur Peru.
"Just like everywhere else, they're disappearing at a terrifying rate," says Vecchio. "Nine years ago, we watched the Nevada Pastoruri, which had been the most popular and accessible glacier for hikers, melt in a period of months into two rapidly receding patches of ice."
"This is something that is really happening, the glaciers are disappearing," he adds. "Most tour operators are not as crass as to say 'Come see glaciers before they're gone' - but they are disappearing."
And the implications of their disappearance will be devastating for Peru, a country that's home to 70% of the world's tropical glaciers, whose population is highly reliant on their runoff.
For Vecchio, who is married to a Peruvian woman and has three children, the topic is personal. What sort of life will his children inherit, he wonders?
Still, Vecchio notes, there are some wonderful hikes remaining in Peru, that get travelers right up to the ice peaks. In the Cordillera Blanca, for instance, there's Quebrada Llaca, which can be done as a day hike out of Huaraz, he says.
"I don't think there is any harm in hiking to where the glaciers are and trying to raise some awareness about them," he says.
Bjarni Freyr has been working on and around Iceland's glaciers since 1996.
He began as a snowmobile guide on one of the country's largest glaciers and is now CEO of Isafold Travel, a company founded in 1997 that specializes in taking travelers to glaciers.
During the time Freyr's been guiding visitors, he's seen tremendous change.
"One measurement I use is the distance we had to walk from our lodge everyday to get up to the glacier," begins Freyr. "In 1996, we had to walk only about 200 meters to get to the glacier. Now -- because it has receded -- we have to walk over a kilometer. That's quite a dramatic change."
In Iceland, the change brings uncertainty and in some cases, opportunity, says Freyr.
"Iceland relies on hydroelectricity, so with the melting of glaciers, there is more water in rivers, so more electricity is generated," he notes. "As long as they're not disappearing, it's a good thing for harvesting electricity...And with the glaciers receding, then the climate in and around the glaciers is warmer, which makes room for more vegetation and things like that. It's not all bad changes. However, there are very different views."
Even Freyr seems to have mixed opinions about the current state of affairs, adding that the disappearance of glaciers would be a very sad development, one he described as an omen of worse developments around the world.
Referring to glaciers as the planet's thermal thermometer, Freyr says that when they're melting, it means less snow is falling, less precipitation is landing on the glaciers and ultimately, something in the world is off balance.
Yet like others, Freyr suggests travelers visiting glaciers may have some benefits.
"In my opinion, the dramatic impact glaciers have on people - seeing the melting and connecting the thought of ice caps melting and disappearing to the fact that the climate is possibly getting warmer - that sort of outweighs the carbon footprint," he says. "That may spur people to take up more environmentally friendly ways of living."
For those interested in viewing some of Iceland's glaciers, Freyr recommends Eyjafjallajökull and also Vatnajökull glacier, which very few people in the world have visited.
Perito Moreno Glacier in Argentina is a UNESCO World Heritage site and holds the world's third-largest reserve of fresh water.
Gina Isaacs was stunned and humbled when she first laid eyes on it.
"My most vivid memory of Perito Moreno was taking a ferry across the lake and staring up at the face of glacier," says Isaacs, who is head of marketing for PanTrek, an online travel tech startup based in Latin America, which promotes travel to the region.
Located in the southern part of Patagonia, Perito Moreno offers breathtaking views of fields of ice and rugged beauty. It is one of many glaciers that form the Los Glaciares National Park and is part of the Patagonian Continental Ice, one of the largest drinking water supplies in the world.
Isaacs says that while visiting Perito Moreno, it's possible to see chunks of ice breaking off from its face, an occurrence that some reports say may be tied to the glacier's continued growth and movement, rather then climate change and melting.
After spending a half day hiking around Perito Moreno, and visiting other glaciers in the region, Isaacs says she left with a renewed respect and understanding.
"There's just something awesome about these glaciers," she says. "They are so old, even the colors are incredible, you see blues and turquoise that you will never see anywhere else."
Glaciochemist Sarah Aciego, who pioneered ice core dating while working at the University of Michigan, regularly takes small groups of travelers to Iceland, Greenland, Antarctica, and the Canadian Rockies to experience glaciers first-hand. During the summer, she leads groups nearly once each month.
Greenland, home to the biggest ice sheet in the Northern Hemisphere, is among the most iconic remaining glacier experiences, says Aciego.
"It's this big white horizon coming toward us," says Aciego. "It's like a tsunami of ice; it looks like a wave of something that's just so massive and unexpected. Usually we see pictures of glaciers from the air. When you go to see an ice sheet in person, it's this huge, huge massive body of ice."
Aciego began taking people to glaciers about a decade ago, starting with her PhD students. On those journeys, the students and she would spend a couple of months at a time at a glacier. All of which has given Aciego a unique perspective regarding the impacts of global warming.
Every visit reveals new changes these days, she says.
"In the Canadian Rockies change is happening incredibly rapidly," she says. "And in Alaska - it's completely different every year we go. What I see in Greenland is a much bigger impact of climate change. Some of the really big glaciers there generate huge icebergs the size of skyscrapers, and they fill up giant fjords. Last year when we were there, the icebergs completely filled a whole bay."
Witnessing such developments is both saddening and concerning, says Aciego. At the same time, Aciego says she would rather travelers come visit glaciers and learn about them and their importance, then perhaps taking a cruise or some other travel activity contributing to carbon emissions.
And ultimately, Aciego says, those involved with climate science have been concerned for a long time. The ongoing discussion and debate about whether to travel to see glaciers, or not, is an important one, and there is no easy answer. Yet as the debate rages on, the glaciers continue their retreat.
"Some of the glaciers in Iceland for sure will be gone in our lifetime," Aciego says. "Many in the Canadian Rockies will for sure be gone in our lifetime. Glacier National Park has so few glaciers in it now...Yeah, they will be gone in our lifetime. To me, when you lose glaciers- it's like losing a species. It's not going to come back."