Several hundred metres down the dark, cold tunnel of an Arctic coal mine, a passageway leads off to a wooden door adorned with the image of a Nordic goddess of fertility, which guards precious treasure. There, the seeds of 17 crops were put in a metal container in 1986, to see how well the permafrost would preserve them far into the future.

The first results are mixed for the “100-year seed project” , a precursor to …