During a closed-door meeting with oil executives at the Vatican on Saturday, Pope Francis gravely warned against further fossil fuel exploration and extraction, arguing that continued use of dirty energy could ultimately “destroy civilization.”

“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.”
—Pope Francis

“Carbon dioxide emissions remain very high. This is disturbing and a cause for real concern,” Francis said in an address at the close of a two-day conference titled Energy Transition and Care of Our Common Home. “More worrying is the continued search for new fossil fuel reserves, whereas the Paris Agreement clearly urged keeping most fossil fuels underground.”

In attendance at the conference were several major players in the oil and gas industry, according to Reuters, including ExxonMobil and Shell—both of which denied the reality of climate change in public for decades despite knowing privately about the threat soaring carbon emissions posed to the planet.

A total of fifty industry executives were reportedly in attendance at the two-day event.