A conservationist cradles two vials of peas destined for deposit in the Svalbard Global Seed Vault. The remarkable facility set on a rugged Arctic island off Norway is the ultimate global safety net for food security. It's able to protect up to 2.25 billion seeds from even "doomsday" scenarios like asteroid impacts and nuclear war.

But crop varieties are already vanishing at an astonishing pace for more mundane reasons, from shifting local weather patterns to disuse by farmers adopting new hybrids. The vault represents a chance to save as many as possible.

"I'd say doomsday is happening everyday for crop varieties," said Cary Fowler, executive director of the Global Crop Diversity Trust, which helps manage the facility. "Lots of people think that this vault is waiting for doomsday before we use it. But it's really a backup plan for seeds and crops. We are losing seed diversity every day and this is the insurance policy for that."

Even a seemingly simple crop, such as wheat, may have 200,000 different varieties. And each variety has a suite of individual traits that determine how it fares in high or low temperatures, during droughts, or against certain diseases or pests.

"Even conservative projections of changing climate now indicate that by mid-century huge areas of some countries, in Africa for example, will be experiencing climates that are unlike any that have existed since the beginning of agriculture in those countries," Fowler explained.

"How will they become adapted to future climates? One way they can is by tapping into this rich storehouse of diversity and breeding new crops with traits that allow them to succeed in those climates. It's essential to future food security," Fowler said.

(Read more about seed banks around the world in National Geographic magazine.)

—Brian Handwerk

Pictures: “Doomsday” Seed Vault Safeguards Our Food Supply

The Svalbard Global Seed Vault off Norway is the Arctic repository of seeds for all the world's crops.