There's something fitting about the decision to site a bastion against the end of the world in a place that looks as if it has already experienced the apocalypse. On 19 June, a construction crew started work on a doomsday seed bank from which the genetic riches of Earth's food crops could, if necessary, be reconstituted. The location: the island of Spitsbergen in the Svalbard archipelago, a desolate place where the winters are long and dark, and polar bears outnumber people.

The island's remoteness, say staff at the Global Crop Diversity Trust, a charitable organization based in Rome that has helped develop the bank, makes it the ideal location to store samples safely. Spitsbergen is free of tectonic activity, and its permafrost would preserve seeds at around −4 °C. Coal from a local mine will be used to power refrigeration units that will further cool the bank to the internationally recommended standard of −20 to −30 °C.

“It's a resource that needs to last for ever,” says Cary Fowler, the trust's director. Fowler says that such a bank is needed in case a species becomes extinct or loses genetic variety through overuse. Some of the three million seeds earmarked for storage could be called upon to thwart a new disease or drought, or even extinctions caused by nuclear war. Although other seed banks exist, the trust is developing the Spitsbergen facility because many banks are poorly maintained and face uncertain futures owing to funding problems.

Norway, which administers Svalbard, will fund the US$3-million construction costs, and the trust will pay for its maintenance, which Fowler estimates at around $100,000 annually. The trust, which expects the facility to be completed by 2007, will also help developing countries prepare and transport seeds to the Arctic.

The bank will be carved into one of the island's sandstone mountains, and will consist of a 50-metre tunnel leading to a storage facility reinforced with one-metre-thick concrete. Seeds will be wrapped in aluminium foil to keep out moisture. The cave will be protected by two high-security doors armed with motion detectors. No full-time staff will oversee the facility, says Fowler, because it is accessible only by an air-strip about three kilometres away, making it relatively easy to track people's comings and goings.

“It's about providing long-term security for crop plants,” says plant scientist Matthew Daws of the Millennium Seed Bank Project at Kew Gardens in London. “It's an insurance policy for countries to deposit some of their collection and have confidence that after thousands of years their seeds will be viable.”