Billionaire tech entrepreneur Elon Musk, who has fathered 10 children, said on Monday the world needs to “make more babies” — and keep digging for oil.

The richest man on the planet, who has repeatedly warned that low birth rates pose a “danger” to civilization, said ahead of an energy conference in Norway that the world is facing a “baby crisis”.

Asked about the greatest challenges facing the world, Musk cited the transition to renewable energies but also said the birth rate was “one of my favourite… things to be concerned about.”

“We don’t want the population to drop so low that we’ll just eventually die,” Musk, founder of American electric car manufacturer Tesla and SpaceX, told reporters in Stavanger, southwest Norway.

“At least make enough babies sustain the population,” he added.

Many Western societies and populated countries such as China are facing declining birth rates and aging societies.

“They say civilization might die with a bang or with a whimper,” added Musk. “If we don’t have enough kids, then we will die with a whimper in adult diapers. And that will be depressing.”

He also said the planet still needed new fossil fuel sources.

“I think realistically we do need to use oil and gas in the short term because otherwise, civilization would crumble,” he said, adding that “some additional exploration is warranted at this time”.

He went on to advocate the maintenance of nuclear power plants, describing himself as “pro-nuclear”.