"Time is running out! Deliberations must go beyond mere exploration of what can be done and concentrate on what needs to be done from today onward," he said.

"We do not have the luxury of waiting for others to step forward or of prioritizing short-term economic benefits. The climate crisis requires our decisive action, here and now," he said June 14 at the Vatican.

The pope spoke to leaders taking part in a conference June 13-14 on "Energy Transition and Care for Our Common Home," sponsored by the Vatican Dicastery for Promoting Integral Human Development and the University of Notre Dame's Mendoza College of Business in the United States.

It was the second private meeting -- the first was in June 2018 -- aimed at dialogue with invited executives of leading energy, petroleum and natural gas companies, global investment firms, climate scholars and academics.

Organizers said that participants this year included CEOs from Royal Dutch Shell, British Petroleum, Occidental Petroleum, ExxonMobil and ConocoPhillips.

Pope Francis thanked participants for returning for the second meeting, saying it was "a positive sign of your continued commitment to working together in a spirit of solidarity to promote concrete steps for the care of our planet."

The dialogue was taking place during a "critical moment," he said, because "today's ecological crisis, especially climate change, threatens the very future of the human family, and this is no exaggeration."

"For too long, we have collectively failed to listen to the fruits of scientific analysis and 'doomsday predictions can no longer be met with irony or disdain,'" he said, citing his encyclical "Laudato Si', on Care for Our Common Home."

It would be grossly unfair for future generations to inherit "a greatly spoiled world," the pope said. "Pardon me if I want to underline this: They, our children, our grandchildren, should not have to pay, it is not right that they pay the cost of our irresponsibility."

All dialogue and action must be rooted in the best scientific research available today, he said, pointing particularly to last year's special report by the Intergovernmental Panel on Climate Change.

"That report clearly warns that effects on the climate will be catastrophic if we cross the threshold of 1.5 degrees Celsius" above pre-industrial levels, as outlined in the Paris Agreement goal, the pope said.

The report, which outlined detailed ways to limit global warming, warned that "only one decade or so remains in order to achieve this confinement of global warming," he added.

"Faced with a climate emergency," the pope said, "we must take action accordingly, in order to avoid perpetrating a brutal act of injustice toward the poor and future generations. We must take responsible actions bearing in mind their impact in the short and in the long term."

Recognizing that "civilization requires energy," he said that it is also important that energy use not destroy civilization.

"A radical energy transition is needed to save our common home," he said, and the Catholic Church was "fully committed to playing her part."

"There is still hope and there remains time to avoid the worst impacts of climate change, provided there is prompt and resolute action," he said.