In Franz Josef village, climate change has a sound and a smell.

It is the sound of heavy machinery passing overhead, rotor blades slicing the air. It is the smell of aviation fuel swirling in the village.

Franz Josef only has 330 ratepayers, but it now boasts 15 helipads from which aircraft lurch into the sky, over Lake Wombat and into the Waiho valley, ferrying visitors back and forth from the glacier. As soon as the noise of one helicopter dissipates, another arrives to fill the empty space; sometimes they seem to move in pairs.

Signs warn about the rise in helicopter usage at Franz Josef.

Glacier Country is not only one of the busiest air spaces in New Zealand, it’s likely one of the busiest in the world. Every year, there are 30,000 helicopter landings in the Westland Tai Poutini National Park, where the glaciers are located. That does not include the return flights, which arrive from outside the park, or the scenic tours that hover high above the ice.

During peak times, there can be as many as one flight per minute at Franz Josef. At nearby Fox Glacier, there are competing resource consent applications for a new heliport: One would have 15 heli-pads and capacity for 400 flights a day.

landings per hour 1995 2009 2014 Landings in the Westland Tai Poutini National Park have increased significantly since 1995. In this graphic, one hour is represented by 10 seconds in order to give a sense of the increase over this period. Helicopters don't actually fly and land at the speed shown.

The constant drone of helicopters has given the once silent valleys a loud thrum similar to that of living by a motorway.

“There’s a smell of Avgas in the town all day,” says Jan Finlayson of the Federated Mountain Clubs.

“It's that Apocalypse Now feeling.”

The helicopters were a direct response to two separate issues. In 2012, the front of Franz Josef glacier collapsed, shedding about 70m of ice from its terminus. Foot access became dangerous, so it was banned, ending more than a century of guided walks directly onto the glacier.

A year later, foot access to Fox Glacier was also cut off when the glacier’s rapid retreat made the ice too unstable, changing the course of the river beneath.

For the first time, the famously accessible glaciers could not be reached by foot which happened sooner than expected. Local guides knew the days of walking onto the glaciers would end, but not when it did.

“When it receded and collapsed - a year ago we thought this is going to happen in the next six months, and it basically happened in the next six weeks,” one local told researchers studying tourism at the glacier.

“It just sort of disappeared really quickly and now the guides are chasing the glaciers as fast as they can.”

Getting people onto the glaciers they came to see required a sharp adjustment - hence, the helicopters.

At the same time, visitor numbers to the West Coast were exploding, which has only become more rapid in the years since.

International visitors to the Westland District have risen from 200,000 to 500,000 per year since 1998, tourism data shows. It rose by 100,000 per year in the last three years alone.

The surge has been particularly apparent among Chinese tourists: in 1998, 315 Chinese nationals visited Westland. Last year, it was 75,000, more than double the number that visited the year before.

Franz Josef has become a focal point for the tension between tourism and natural values, a battle emerging in many pockets of the country. The helicopters in Glacier Country have effectively created two classes of tourist: those who can afford to pay $350 per person for a helicopter flight onto the ice, and those who cannot, or will not, pay for that privilege.

It has also been a balancing act for the Department of Conservation (DOC), which has many responsibilities as manager of the park. They include protecting the “natural quiet” of the landscape while also allowing for tourist access, which in this case are directly at odds.

On a particularly hectic day this year, the sprawling car park at Franz Josef was full to bursting. But the cars kept coming.

DOC rangers became traffic wardens, directing the cars to park on a long berm to wait for those who had seen the glacier to leave.

“We had up to 60 people parked [on the berm] on the worst days, with a half hour wait,” says Wayne Costello, the park’s operations manager.

“We’re not wanting to do that again.”

In the busiest months, at the height of summer, tens of thousands of people walk the valley track to Franz Josef glacier.

More parking is required, but that would mean building further into the national park, which would likely be unpopular. DOC is looking at a park and ride service with regular shuttles from the township.

Because of the crowds, toilets need to be cleaned more often, and the sewage infrastructure checked more frequently. Recently, there has been an increase in people offering unauthorised guided tours: DOC has spoken to 80 people believed to be offering tours without concessions, some of whom are now being prosecuted. The remote wilderness of the national park becomes chaos.

“In that central block, the summer period, it’s just chokka,” Costello says.

“Every accommodation provider from Haast to Lake Brunner is just completely chokka, and everyone’s coming here.”

This has all happened in an environment that is increasingly risk-prone, and where the star attractions are getting further and further away.

Since 2008, when the current period of retreat began, the path and viewing platform at Franz Josef has been moved closer and closer to the glacier, which keeps moving backwards.

The path had to be built across dead ice, which melts and causes the track to slump. There are issues with rocks falling from the valley walls, which become unstable without the glacier holding them back.

At Franz, the track is now as close as it can go: “We’ve gone into the valley as far as we safely can,” Costello says. “We won’t go any further.”

Now that the glacier has been chased to its farthest point, the continued use of helicopters seems inevitable.

“They provide people a really nice perspective of the park, and give a great appreciation of the glaciers and the mountains, of the scale of the park in terms of a mountain to sea view in a really easy way that’s not going to be that accessible unless you’re really fit and able in terms of technical experience to get to those high up places.”

Climate change has had other effects on the area, too. Ex-tropical cyclone Fehi closed access to Fox Glacier for 56 days, over the town’s peak season. The road had to be rebuilt, as did a walking track.

As the glaciers retreat, the valley walls become more fragile, creating rockfall hazards. At Fox Glacier, which is particularly unstable, ice patches are effectively holding up the valley walls; when they melt and the walls collapse, the rocks are swept down the valley.

“One of the side valleys is sort of collapsing into its own little valley, so there’s more or less a mountainside falling down into the valley floor and then all of that material was getting washed downstream and coming into the Fox valley where it’s just about causing a dam,” Costello says.

“At some stages [hazard zones] can be quite quiet, and other times can throw down house sized boulders with random abandon, and you obviously don’t want anyone anywhere near them.

“It’s interesting times.”

Some believe DOC has given too much to tourism in the park. Jan Finlayson points out that allowing for tourism is the last of DOC’s functions listed under the Conservation Act - protecting natural values is first, followed by fostering recreation.

She noted the irony of DOC allowing international visitors, who arrived on planes, to take helicopter flights onto a landmark disappearing due to greenhouse gas emissions.

“DOC probably has a far greater than equal responsibility for taking action against climate disruption, which means saying no to frivolous helicopter activity,” she says.

“It’s noise pollution, too. Defence of natural quiet means you limit helicopter activity, you limit anthropogenic noise as much as possible.”

What was happening at the glaciers - expensive activities for tourists, at the expense of the traditional backcountry experience - was a departure from New Zealand’s values, Finlayson says.

“We’re in a position where so many people want to come here, we can afford to be ourselves.

“Bending over backwards to be something we’re not, something Disney-ified… it’s not a good way ahead. Tourism is inherently at its best when it’s not making a trail of wreckage, either socially or environmentally.”

A helicopter picks up tourists from the glacier.

The glacier’s tongue can receive about 11m of rain per year, making it one of the wettest places in the country. Clouds and mist descend over the glacier, which make it famously gloomy but suboptimal for flying heavy machinery.

Helicopters can be grounded for up to a week at a time. It’s why one of the biggest tourism operators in the area is pursuing something ambitious.

Skyline operates helicopter flights to the glaciers, but wants to build a gondola, like the ones it runs in Queenstown and Rotorua, to take visitors to the top of Franz Josef.

It would be a permanent resolution to the problem of “chasing the glacier” as it retreats.

“Fifty per cent of the time, or thereabouts, weather prevents helicopter flights,” says Skyline chairman Mark Quickfall.

“A lot of people who travel down the Coast miss out. We’d imagine it would be similar to the gondola we operate in Queenstown, where there are very few days it can’t operate.”

There are many obstacles to overcome. Building anything in a national park is difficult, as it must be allowed for in DOC’s park management plan. Gondolas are expensive and obtrusive, and may not even be technically feasible in that environment; there are likely cultural and environmental issues to consider, too.

But the signs are promising. DOC is reviewing the park’s management plan now, and it may include an amenity area, allowing for the gondola to be built. Technical and geological work is well underway, and there is local support for the project, Quickfall says.

“It’s really a marathon, not a sprint. The gondola itself won’t be on the glacier, it’ll run on the left hand side. It’s a big landscape at Franz, so if you stand in the car park and you look up, it’ll disappear into the distance. It won’t be in your face.

“We have canvassed people wide and far, and the response has been very favourable.”

In other parts of the world, the responses to glacial retreat have been varied. A Swiss ski resort placed a reflective blanket on part of a glacier to fight back the sun; Norway has a popular glacier museum, with information about glacial retreat; China’s Xinjiang region banned glacier tourism entirely.

New Zealand’s response thus far has been to chase the glaciers higher up the mountain.