OSLO - The world is running out of time to develop new seed varieties to confront climate change and head off food shortages that could affect billions of people, experts said.

Marking the first anniversary on Thursday of the opening of a "doomsday" seed vault on the island of Spitsbergen in the Norwegian Arctic, they said that people in Africa and Asia were most at risk from a lack of climate-proof crops.

"It’s a question of urgency," Cary Fowler, head of the Global Crop Diversity Trust, told Reuters by telephone with other experts from Spitsbergen. He said governments needed to invest more in breeding new seeds.

"Unlike the bank that needs to be bailed out this week, this problem is going to be an emergency 20 years from now. But by then it will be too late" he said.

The vault, blasted from icy rock 1,000 km (600 miles) from the North Pole, opened on February 26, 2008 and has doubled its holdings to 200 million seeds in the past year, representing 400,000 varieties. It is run by the trust, the Norwegian government and the Nordic Genetic Resource Center in Sweden.

"My opinion is that not enough is being done" to develop new varieties of crops, said David Lobell, an expert in food security and the environment at Stanford University.

There was work under way to help develop crops that can withstand drought and floods but exposure to very high temperatures had not been a focus historically, he said.

Priorities could be southern Africa to help people heavily dependent on crops such as maize in a region likely to be hard hit by climate change, he said. Similarly, India and Pakistan faced disruptions to crops such as rice and wheat.

"We need some tremendous advances," said David Battisti, an atmospheric sciences professor at the University of Washington.

"The whole world will be stressed at the same time" because of global warming, he said. Crops can take a decade to breed and test, with no guarantee of success.

Battisti authored a study in the journal Science last month that predicted that climate change would disrupt growth by both crops and livestock and cause serious food shortages for half the world’s population.

Crops cannot simply be moved to new areas as the climate warms because soils, pests, insect pollinators, daylight hours and other factors differ even if temperatures seem suitable.