The door will open on Tuesday on an Arctic “doomsday” vault that will safeguard seed samples from the world’s most important food crops against possible disaster, in scenarios from drastic climate change to nuclear war.

The first seeds – of rice plants – are to be delivered this morning to the Svalbard global seed vault, dug out of a snow-covered island 800 miles (1,280km) from the North Pole. They will be kept at 18°C below freezing. The intention is to preserve hundreds of millions of seeds from varieties of nearly 100 of the world’s main crops.

“It’s an insurance policy,” said Cary Fowler, executive director of the Global Crop Diversity Trust, which built the vault with $8m (€5.4m, £4.1m) from the Norwegian government.

In the event of a sudden disaster such as a nuclear attack or an asteroid strike, the seed bank would hold the means to restock the Earth’s agriculture.

It would also protect against the much more likely – some scientists would even say inevitable – effects of global warming by providing seeds for researchers to breed new crops that can to cope with a changing ­climate.

Mr Fowler explained: “We are losing crop varieties and crop diversity all over the place ... [even as] climate change is affecting the way some crops grow.”

He pointed to varieties of rice sensitive to temperature rises much smaller than those forecasted by climatologists as the result of global warming: if exposed to a temperature rise of 1°C during a crucial period of growth, the crop’s yield is cut by one-tenth.

If agricultural scientists could find strains of rice that were able to withstand higher temperatures, they could breed varieties to maintain yields.

At present, there is no single seed repository. Collections are maintained haphazardly worldwide, meaning samples are lost. Sometimes samples of potentially important varieties of plants, along with the genes that could have conferred benefits on new plants, become extinct.

Seeds from the 1.5m crop varieties known to be in the world’s collections will be sent to Svalbard, which will form the repository of last resort, dispensing seeds for crop varieties to be regrown only when all other known examples are gone.

Tuesday’s delivery of seeds will be attended by José Manuel Barroso, the president of the European Commission, and Jens Stoltenberg, the prime minister of Norway.

The Global Crop Diversity Trust has raised $100m of the endowment of about $300m needed for the upkeep of the vault and the process of collecting and experimenting on seeds.

Samples will be kept in watertight foil packets behind blastproof doors and concrete walls a metre thick. The vault’s remote location – 60m under the permafrost of the island of Spitsbergen, in the archipelago of Svalbard, one of the most northerly points of land on Earth – is intended to keep the seeds at the low temperatures required while also safe from intruders.