There's a bank in Lima, Peru that holds contents so valuable, they're hidden behind a thick metal door in an earthquake-proof vault. They're not lost Inca gold or mounds of jewels, but thousands and thousands of potato seeds.
Seed banks serve as a kind of genetic Noah's Ark for crops, keeping copies of as many different species of crops as possible to ensure food security in the future. These seeds are valuable because they are part of a global movement to preserve crop diversity.
"There's a huge, long chain that goes from growing food to people eating it, and at the very beginning of that chain is conservation of diversity of crops," said Colin Khoury, a researcher associate at the United States Department of Agriculture's Agricultural Research Service. "In the past, that conservation wasn't so necessary. But over the last 100 to 150 years, we've started to lose that diversity of the fields."
Traditionally, farmers' fields would be filled with a variety of crops and a variety of species within those crops—you wouldn't have acre upon acre of Roundup Ready corn, you'd have a dozen or so varieties of corn all growing alongside each other, Khoury explained.
But as our farming systems have expanded and become more industrialized, they've also become more uniform. To grow enough corn to feed millions of Americans, it's a lot easier if all of the corn is the same, so the equipment and techniques used can be identical across the system.
While this industrialization has benefits—we can feed more people this way—there are also risks. By having only one or two varieties of a given crop, it makes it that much easier for insects and pathogens to figure out how to attack. Plants that were naturally resistant to a particular pests may lose that resistance as the pest comes into contact with it more often and evolves ways around that defense.
We saw this taken to the extreme during the Irish potato famine. In the mid-1800s, much of Ireland (especially the rural poor) relied almost exclusively on potatoes for their diet.
When an outbreak of blight began to decimate the potato crops, 1 million people died from starvation or related disease. There were other factors that contributed to the famine, but the reliance on a monoculture of potatoes proved a deadly bargain.
To counter this in the modern age, we rapidly develop slightly different varieties to roll out into our fields, Khouly explained.
"Plant breeders will keep the traits that farmers want, like a tomato that grows on the vine at the right height to be harvestable by machine, but they'll breed certain things to keep up with pests or diseases," Khouly said. "Essentially it's like buying into a very big machine that has to run faster and faster to keep up."
In order to ensure we can continue this process, we need to have lots of genetic materials from which to mix and match. That's where the seed banks come into play.
The Lima-based International Potato Center is just one of thousands of seed banks around the world. Potatoes have been a staple in the diet of many of Peru's indigenous cultures, and hold cultural significance, so it made sense for the CIP (the International Center for Potatoes' Spanish acronym) to be based there and start its seed collection.
"We have a chance to preserve the diversity that has accumulated through thousands of years of evolution and domestication," said Ana Panta, an in-vitro conservation specialist at CIP. "Potatoes were first cultivated more than 8,000 years ago and along the way, those ancient varieties accumulated valuable genes, like resistance to disease."
There are more than 4,500 varieties of potatoes—and 7,000 types of sweet potato—preserved at the bank, representing 80 percent of the world's potato genes. By preserving these seeds, plant breeders can have access to the genes of thousands of varieties to mix and match and create new species to help us preserve our farming systems.
But the CIP doesn't stop there, they're allowing these varieties to continue to evolve in the field. A project called Parque de la Papa brings together different indigenous communities from the Andes to continue cultivating local varieties of potatoes, which lets the potatoes naturally evolve and produce even more species to work with.
Seed banks are often overlooked as an important part of our food system, but as the world population continues to balloon, and resources like water and land become more scarce, we're going to need to double down on our efforts to ensure food security. The United Nations has said we need to increase our food production by 60 percent just to feed everybody by 2050, and an essential part of that will be protecting the world's seed banks.
"It's essential for combating hunger and the future problems humanity will face with climate change," Panta said. "This is why it's important to preserve these."