VATICAN CITY (AP) — Pope Francis warned oil executives on Friday that a “radical energy transition” to clean, low-carbon power sources is needed to stave off global warming as he pressed his environmental message in a closed-door Vatican summit.

Francis also told industry leaders from the likes of Britain’s BP and Italy’s Eni that carbon pricing and science-based transparent reporting of carbon risks were essential to ensure the poorest don’t suffer any more from the effects of climate change.

Francis told the executives that a well-managed transition away from polluting fuels can “generate new jobs, reduce inequality and improve the quality of life for those affected by climate change.”

The meeting marked the second year in a row that Francis has invited oil and financial sector executives to the Vatican to impress upon them his concern that preserving God’s creation from global warming is one of the fundamental challenges facing humankind today. Francis has dedicated a major teaching document to the environment and is expected to press his case at a Vatican meeting of Amazon bishops later this year.

Outside the summit, around half-a-dozen protesters held up signs urging the oil executives to listen to the pope.

The meeting was held under unusual secrecy even by Vatican standards, with the program and guest list initially unpublished. A few executives confirmed their presence ahead of time, including the chief executives of BP and Eni, Bob Dudley and Claudio De Scalzi.

On the BP blog, Dudley wrote this week that the meeting was coming at an urgent time, with BP’s own latest survey showing carbon emissions grew by 2% last year, at a time when they have to dramatically decrease to meet standards set by the Paris climate accord.

Francis told the executives that carbon pricing is “essential” so that the poorest don’t pay the debt of the wealthy in future generations.

He also called for transparency in reporting climate risks and recalled that in his first meeting with the executives last year, he voiced concern that our thirst for energy must not destroy civilization.

“Today a radical energy transition is needed to save our common home,” he said.