Watch the program: Part 1 | Part 2

La Paz, Bolivia. Altitude: 3,800 metres. When your hotel offers both llama burgers and bottled oxygen on room service, you know that the assignment is going to be a little different.

We stumble gasping, jet lagged and unacclimatised off the plane at La Paz after a two-day journey from Australia, to film a story on the latest casualty of climate change - Bolivia’s rapidly melting glaciers.

Having digested the llama, sucked on some O2 and drunk copious amounts of coca tea - which every Bolivian insists is the best cure for altitude sickness - I contemplate our next move.

If nearly two million Bolivians can happily live and work at this altitude, then so will we.

The only problem is getting to the story. We’ll have to go even higher, ascending to a dizzying 5,500 metres - where there is only half the oxygen of sea level.

This may be regarded as a mere warm-up session for your average mountain climber, but they spend weeks acclimatising, whereas we’ve only two days to catch our breath.

We meet up with local glaciologist Edson Rameriz, our guide up the Chacaltaya Glacier, which stands within sight of the city. Edson says the high altitude glaciers around La Paz are melting at an unprecedented rate.

He predicts they will all disappear within 20 years.

It’s a crisis in the making for La Paz and the twin city of El Alto. The glaciers act as giant water reservoirs - providing up to 60 percent of the drinking water. Hydroelectric plants rely on water-run off to generate nearly 80 percent of the cities’ power.

Chacaltaya was once billed as the world’s highest ski run, but as we ascend the 5,500-meter mountain it looks more like a ski resort on the moon. An old European-style ski lodge sits atop the rocky lunar landscape.

Edson leads us scrambling across the precariously steep slope towards the Chacaltaya glacier, now reduced to a sad sliver of ice.

We stumble past the remains of the ski lift that stopped operating in 1998. Loaded up with camera gear, it’s hard enough just breathing at this altitude, let alone imagining a downhill run.

Edson scratches at the black ice, exposed to the sunlight for the first time in 18,000 years. This is ancient history melting before our very eyes. In two years, says Edson, it will all be gone, and with it will go the precious water vital to sustaining life on the arid western side of the Andes.

The high altitude has its compensations. The thin air makes visibility perfect. We stand on the dripping ice awed by the spectacular vista of the Andes range. But all Edson sees is a bleak, very dry future.

He views Bolivia as the first country to encounter a disaster that will eventually confront tens of millions of people across South America. "It’s a critical problem - it’s the same problem for Peru, Ecuador and Colombia - all the Andes," says Edson. "It’s very sad."

-- From Producer Mark Corcoran