Pope Francis, addressing top oil company executives, said that the world must convert to clean energy and warned that climate change risked destroying humanity.

"Civilisation requires energy but energy use must not destroy civilisation," he told the high-profile group on Saturday at the end of a two-day conference in the Vatican.

He said climate change was a challenge of "epochal proportions", adding that the world needed to come up with an energy mix that combated pollution, eliminated poverty and promoted social justice.

The unprecedented conference, held behind closed doors at the Pontifical Academy of Sciences, brought together oil executives, investors and Vatican experts who, like the pope, back scientific opinion that climate change is caused by human activity and that global warming must be curbed.

"We know that the challenges facing us are interconnected. If we are to eliminate poverty and hunger ... the more than one billion people without electricity today need to gain access to it," the pope told them.

"But that energy should also be clean, by a reduction in the systematic use of fossil fuels. Our desire to ensure energy for all must not lead to the undesired effect of a spiral of extreme climate changes due to a catastrophic rise in global temperatures, harsher environments and increased levels of poverty," he said.