Pope Francis said on Friday that carbon pricing, used by many governments to make energy consumers pay for the costs of burning fossil fuels, was “essential” to stem climate change.

The comment, the Pope’s clearest statement to date on the issue, was made in an address to leaders of the world’s top energy companies at the end of a two-day meeting, according to Reuters.

He also called for “open, transparent, science-based and standardised” reporting of climate risk and a “radical energy transition” away from carbon to save the planet.