Eight years after publishing a landmark thesis outlining the devastation of manmade climate change, the 86-year-old pontiff published a follow-up that warned that some damage was "already irreversible."
"With the passage of time, I have realized that our responses have not been adequate, while the world in which we live is collapsing and may be nearing the breaking point," he wrote.
But the next round of the United Nations climate talks opening in Dubai on November 30 "can represent a change of direction," with real commitments to moving from fossil fuels to clean energy sources such as wind and solar, he said.
FILE - The book "Laudato Deum " ("Praise Be To You"), a thesis by Pope Francis on climate change is pictured in a book shop the day of its released, on October 4, 2023 near The Vatican.
The Argentine pontiff's 200-odd page 2015 text, "Laudato Si" ("Praise Be To You"), was an influential call to arms to protect the Earth and sparked global debate unprecedented for a religious text, including commentaries in scientific journals.
Months later, there was a breakthrough in U.N. climate talks in Paris, with nearly every nation on Earth committing to limit warming to "well below" two degrees Celsius above pre-industrial levels.
But the U.N. warned last month that the world is not on track to meet these goals, while climate monitors predict 2023 will be the hottest in human history, with the Northern Hemisphere's summer marked by heatwaves, droughts and wildfires.
FILE - This Wednesday, Nov. 26, 2008, file photo, shows solar panels on the roof of the Paul VI Hall, at the Vatican.
In his follow-up Wednesday, running to 12 pages in the original Spanish, Francis expressed hope "that COP28 will allow for a decisive acceleration of energy transition, with effective commitments subject to ongoing monitoring."
He called for "binding forms of energy transition that meet three conditions... efficient, obligatory and readily monitored."
Only a real commitment to change "can enable international politics to recover its credibility," wrote the pope.
He referenced concerns about the U.N. talks being held in oil-rich United Arab Emirates, noting that while it was a "great exporter of fossil fuels" it also made "significant investments" in renewable energy sources.
FILE - People hold a banner reading ' Climate action Now ' in St. Peter's Square, at the Vatican, Sunday, June 28, 2015.
"To say that there is nothing to hope for would be suicidal, for it would mean exposing all humanity, especially the poorest, to the worst impacts of climate change," wrote Francis.
The original text stated clearly that humanity was to blame for global warming -- a message the pope said he felt required to repeat due to the power of climate scepticism.
He described "certain dismissive and scarcely reasonable opinions that I encounter, even within the Catholic Church."
"Despite all attempts to deny, conceal, gloss over or relativise the issue, the signs of climate change are here and increasingly evident," he wrote.