Peru's darling crop, the potato, has defied the capricious climate of the Andes for millennia, morphing into 2,500 varieties.
But after 8,000 years of domestication, the tuber faces a grave threat to its continued South American habitat, with growers running out of mountain terrain within which to plant. Warming temperatures are forcing farmers to cultivate their spuds at higher altitudes, as less resilient forms succumb to rampant disease and insect plagues below.
That's putting the Andean staple at grave risk, signaling the potential for famine and the unraveling of folkloric customs in indigenous communities scattered amongst the region's snowcapped peaks and valleys.
Though not all of Peru's growers are taking it lying down.
It's tied up in the Andean identity and cosmo-vision. In addition to its nutritional and social value, all their beliefs are in tune with potato cultivation.
In the Inca heartland of the Sacred Valley, five Quechua-speaking villages are working with modern science to blunt impacts from climate change.
The 6,000 families make up the world's first "Potato Park," a 9,200-hectare (22,700-acre) living laboratory near Cuzco, where residents and scientists are testing the tolerance of various potato varieties against severe drought and frost.
"It's extremely clear that temperatures have risen, as potatoes that 30 years ago used to grow between 2,800 and 3,500 meters above sea level, now grow from 4,000 to 4,200 meters," Lino Loaiza, of the Association for Nature and Sustainable Development (ANDES) that assists the Pisac-based park, told VICE News.
So-called "potato guardians," or papa arariwa, within the park communally work the land according to Andean principles of reciprocity, while researching 700 varieties for signs of climate change adaptation.
Set up in 1997 by ANDES, the project has identified 12 drought resistant types, with up to another 64 showing signs of adjusting to increasingly erratic seasonal temperature and precipitation changes.
"The rains don't fall like they used to, the glaciers are receding, the lakes are lower, and the winds stronger. It's a great concern and the reason for our research," Loaiza, with 30 years of potato-farming experience said, adding corn has now risen to where the farmers formerly sowed potatoes.
Nearly 700 miles to the west, in the capital Lima, where the Andes cascade down into to Peru's Pacific coast, the International Potato Center (IPC) has created a potato gene bank. With a collection of about 70 percent of the world's 4,500 total varieties, cloned and cryogenically frozen, it sends plants around the world to be planted at varying elevations and monitored for their response to different climate conditions.
"Our goal is to preserve the genetic diversity in potatoes, sweet potatoes, and nine Andean root and tuber crops for perpetuity," David Ellis, head of the gene bank told VICE News, hovering over a mini-museum of multi-colored gnarled specimens ranging from papa huayro to k'achun waquachi.
The world's largest tissue culture bank has "repatriated" 30 percent of its collection to 67 indigenous communities — and 410 to the potato park. "We increase the diversity available to them by giving back what their grandfathers planted," Ellis added.
While science is safeguarding against vanishing varieties in the Sacred Valley, it must be rolled out throughout the whole of the Andes, the longest continental range in the world, according to Alberto Salas, a veteran potato specialist at the IPC.
"The mountains are pyramids. The higher you go, the slenderer the land becomes, as do your growing possibilities," the Peruvian, who's handled 60 percent of the collection, said. "In approximately 40 years there could be a catastrophe.
Just one percent, or about six potato types, are widely accessible in Peruvian markets.
In the Andes, subsistence farmers stockpile the more rare native potatoes to be eaten throughout the year, while surpluses are infrequent. 4,500 meters is the maximum elevation.
With temperatures oscillating between five and 24 degrees Celsius in the summer, and -20 and -5 in the winter, little else grows except for potatoes and grains, like quinoa.
The potential of under-utilized spuds, rich in vitamins and nourishment, is huge. "The genes exist, but what's lacking is government action," Salas added.
Per capita potato consumption has dwindled from 265 pounds in 1950 to 187 pounds in 2014, as diets have moved toward rice, up from 29 pounds to 119 pounds in the same period, according to Peru's agriculture ministry.
Meanwhile, plantings have fallen from 740,000 acres to 593,000 acres, the IPC said. Falling demand and workers ditching fields for mining jobs, where salaries could be four times that of Peru's minimum monthly wage, were also contributing to falling potato yields, Salas added.
As Peruvian society modernizes and the climate shifts, the potato's centrality to Andean society is at threat.
"Communities are organized around potato-growing at these altitudes," Ramiro Ortega, an agronomist and retired professor at the Universidad Nacional San Antonio Abad in Cuzco, said.
"It's tied up in the Andean identity and cosmo-vision. In addition to its nutritional and social value, all their beliefs are in tune with potato cultivation," Ortega added.
Potatoes are blessed at spiritual ceremonies with Pachamama, frequently translated as Mother Earth, and given at baptisms and weddings.
Indeed, one knobby, fiendishly hard to peel variety, known as "the one that makes the bride cry" is given by a potential mother-in-law to assess the suitability of their son's fiancée.
Back in Lima, native potatoes have enjoyed resurgence off the back of a gastronomic boom that has propelled Peruvian cuisine internationally.
Gaston Acurio, a lauded celebrity chef and potential contender in 2016's presidential election, is among several cooks harnessing the potatoes' distinctive tastes in the capital's swanky restaurants.
The global temperature has already risen one degree Celsius from pre-industrial levels and, with another degree likely, more strife is in store for the world's third most-consumed crop.
"Potato is the daily bread for campesinos," Loiaza of ANDES said. "If it's not at every meal, the table is missing something. Without the potato, the people won't be able to live."
Photos by Alex Pashley
Follow Alex Pashley on Twitter: @A_Pashley